history of life on earthintervention.roodie.co.za/assets/files/gr10lsweek36.pdf · • late...
TRANSCRIPT
History of life on Earth Mass Extinctions
Agenda or Summary LayoutA summary of the topics discussed
1
2
3
4
Discussion Item OneExplanation of Mass extinctions
Discussion Item TwoThe five major mass extinctions
Discussion Item ThreeTwo particular Extinctions
Discussion Item FourSixth major extinction
Mass Extinctions
Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists
Remember that there are two types of extinctions
They are natural and man made extinctions
Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed
But there are times when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years
This is called a mass extinction
What are they
The Five Major Mass Extinctions
The earliest known mass extinction occurred about 439 million years ago and was caused by a drop in sea levels
The sea levels dropped because of the formation of glaciers
The sea levels rises as the glaciers started to melt
The first mass extinction
The Five Major Mass Extinctions
The second extinction occurred about 364 million years agoIt is not known what caused this extinction
The third extinction occurred about 250 million years agoIt may have been caused by comet or asteroid impact or volcanic floods
The second and third mass extinction
The Five Major Mass Extinctions
The fourth mass extinction occurred about 199 million to 214 million years ago
It was caused when volcanoes erupted releasing large amounts of lava
This is turn lead to global warming
The fourth mass extinction
The Five Major Mass Extinctions
The fifth mass extinction occurred about 65 million years ago
There are several possible causesbull asteroid impact on the Yucatan Peninsula which is in
the Gulf of Mexicobull gradual climate changebull volcanic eruptions
The fifth mass extinction
Two Particular Extinctions
Of the five mass extinctions two stand out
These were the one that occurred 250 million years ago and the one that occurred 65 million years ago
The mass extinction that occurred 250 million years ago was the most serious one
The most famous mass extinction occurred 65 million years ago the extinction of the dinosaurs
Two Particular Extinctions
During this extinction almost 90 all species became extinct
This included 84 of marine genera and about 70 of land species plants insects and vertebrate animals
The mass extinction of 250 million years ago
Two Particular Extinctions
The dinosaurs appeared about 245 million years ago
They flourished during the Jurassic Period
This period occurred about 208 to 143 million years ago
The dinosaurs dominated the land and air and some of them even lived in water
Two Particular Extinctions
Birds and mammals also existed during this time
The dinosaurs then became extinct in a short period of 10 million years
This occurred about 65 million years ago
Of the marine families 16 marine genera 47 and 18 of the land vertebrate families also became extinct during this time
The mass extinction of 65 million years ago
Two Particular Extinctions
Scientists are not sure about the exact cause of this mass extinction
However the following are some of the conditions that occurred during this timeo there was a sharp drop in temperatureo the water of the seas evaporates
The mass extinction of 65 million years - Causes
Two Particular Extinctions
Many of the plants the source of food for the dinosaurs died out
Iridium was found in a thin layer of clay
Iridium is an element that is very rare on earth but common in meteorites
A huge crater was found in the Caribbean Sea
There were many volcanic eruptions in India
The mass extinction of 65 million years - Causes
Two Particular Extinctions
The above evidence lead to the formation of three hypothesis
The most common hypothesis is that an asteroid crashed onto Earth causing global climate change
The climate change lead to the mass extinction
The layer of iridium and the large crater in the Caribbean sea support this hypothesis
The mass extinction of 65 million years ago - Hypothesis
Two Particular Extinctions
This hypothesis deals with the continental drift theory movement of continents away from each other
It is believed that the continental drift led to the climate change
The mass extinction of 65 million years ago- Hypothesis 2
Two Particular Extinctions
This hypothesis deals with the volcanic activity in India
It is believed that this volcanic activity released particles into the air
These particles blocked out the sun for a long period of time
This resulted in the lowering of temperatures on Earth
Therefore many species died out because they could not adapt to the low temperature
The mass extinction of 65 million years ago ndash Hypothesis 3
Two Particular Extinctions
Scientists accept all three theories
Mass extinction was caused by climate change
The climate change was caused by the asteroid impact and volcanic activity
The mass extinction of 65 million years
The Holocene Epoch
The next major extinction is occurring presently
This is the sixth mass extinction
Human exploitation of the environment is the cause of this mass extinction
It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction
Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time
The sixth major extinction
Terminology
Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists
Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed
Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years
Jurassic Period period when dinosaurs flourished
Something for you to do
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
4 The first mass extinction was caused byhellip
A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above
5 The most famous extinction took placehellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and airB Water and airC Land and airD Water and land
9 Iridium ishellip
A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction
Solution
1 B
2 A
3 C
4 D
5 A
6 C
7 B
8 D
9 A
10 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 1 of 15
Mass extinctions
A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major
mass extinction events in Earths history
These are shown in the table given along with the major events that characterised each
Learn about the five major mass extinctions that occurred in Earths history
Video 2CY4
Five of the following extinction events are recognised (listed from the most recent at top of the list to the
earliest oldest at bottom of list
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
bull End-Triassic
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull Late Devonian
bull Late Ordovician
Major mass extinction event
Date of occurrence
Major events
Cretaceous-Paleogene extinction event
65 million years ago
Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates
Triassic-Jurassic event
205 million years ago
Most non-dinosaur species were eliminated leaving land dinosaurs with no competition
Permian-Triassic event
250 million years ago
This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection
Late Devonian extinction
375ndash360 million years ago
This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated
Ordovician-Silurian extinction event
450ndash440 million years ago
Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 2 of 15
Causes of mass extinctions (ESGCW)
Watch a video about the debate about what really killed the dinosaurs
Video 2CY6
There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory
to explain what caused mass extinctions the theory must
bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg
dinosaurs)
bull Explain why some organisms died and others survived
bull Be based on natural events and processes that are shown to have occurred around the time of
extinction
Two of the hypotheses put forward are
bull the impact theory of extinction
bull massive volcanic activity
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 3 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 5 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Agenda or Summary LayoutA summary of the topics discussed
1
2
3
4
Discussion Item OneExplanation of Mass extinctions
Discussion Item TwoThe five major mass extinctions
Discussion Item ThreeTwo particular Extinctions
Discussion Item FourSixth major extinction
Mass Extinctions
Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists
Remember that there are two types of extinctions
They are natural and man made extinctions
Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed
But there are times when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years
This is called a mass extinction
What are they
The Five Major Mass Extinctions
The earliest known mass extinction occurred about 439 million years ago and was caused by a drop in sea levels
The sea levels dropped because of the formation of glaciers
The sea levels rises as the glaciers started to melt
The first mass extinction
The Five Major Mass Extinctions
The second extinction occurred about 364 million years agoIt is not known what caused this extinction
The third extinction occurred about 250 million years agoIt may have been caused by comet or asteroid impact or volcanic floods
The second and third mass extinction
The Five Major Mass Extinctions
The fourth mass extinction occurred about 199 million to 214 million years ago
It was caused when volcanoes erupted releasing large amounts of lava
This is turn lead to global warming
The fourth mass extinction
The Five Major Mass Extinctions
The fifth mass extinction occurred about 65 million years ago
There are several possible causesbull asteroid impact on the Yucatan Peninsula which is in
the Gulf of Mexicobull gradual climate changebull volcanic eruptions
The fifth mass extinction
Two Particular Extinctions
Of the five mass extinctions two stand out
These were the one that occurred 250 million years ago and the one that occurred 65 million years ago
The mass extinction that occurred 250 million years ago was the most serious one
The most famous mass extinction occurred 65 million years ago the extinction of the dinosaurs
Two Particular Extinctions
During this extinction almost 90 all species became extinct
This included 84 of marine genera and about 70 of land species plants insects and vertebrate animals
The mass extinction of 250 million years ago
Two Particular Extinctions
The dinosaurs appeared about 245 million years ago
They flourished during the Jurassic Period
This period occurred about 208 to 143 million years ago
The dinosaurs dominated the land and air and some of them even lived in water
Two Particular Extinctions
Birds and mammals also existed during this time
The dinosaurs then became extinct in a short period of 10 million years
This occurred about 65 million years ago
Of the marine families 16 marine genera 47 and 18 of the land vertebrate families also became extinct during this time
The mass extinction of 65 million years ago
Two Particular Extinctions
Scientists are not sure about the exact cause of this mass extinction
However the following are some of the conditions that occurred during this timeo there was a sharp drop in temperatureo the water of the seas evaporates
The mass extinction of 65 million years - Causes
Two Particular Extinctions
Many of the plants the source of food for the dinosaurs died out
Iridium was found in a thin layer of clay
Iridium is an element that is very rare on earth but common in meteorites
A huge crater was found in the Caribbean Sea
There were many volcanic eruptions in India
The mass extinction of 65 million years - Causes
Two Particular Extinctions
The above evidence lead to the formation of three hypothesis
The most common hypothesis is that an asteroid crashed onto Earth causing global climate change
The climate change lead to the mass extinction
The layer of iridium and the large crater in the Caribbean sea support this hypothesis
The mass extinction of 65 million years ago - Hypothesis
Two Particular Extinctions
This hypothesis deals with the continental drift theory movement of continents away from each other
It is believed that the continental drift led to the climate change
The mass extinction of 65 million years ago- Hypothesis 2
Two Particular Extinctions
This hypothesis deals with the volcanic activity in India
It is believed that this volcanic activity released particles into the air
These particles blocked out the sun for a long period of time
This resulted in the lowering of temperatures on Earth
Therefore many species died out because they could not adapt to the low temperature
The mass extinction of 65 million years ago ndash Hypothesis 3
Two Particular Extinctions
Scientists accept all three theories
Mass extinction was caused by climate change
The climate change was caused by the asteroid impact and volcanic activity
The mass extinction of 65 million years
The Holocene Epoch
The next major extinction is occurring presently
This is the sixth mass extinction
Human exploitation of the environment is the cause of this mass extinction
It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction
Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time
The sixth major extinction
Terminology
Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists
Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed
Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years
Jurassic Period period when dinosaurs flourished
Something for you to do
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
4 The first mass extinction was caused byhellip
A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above
5 The most famous extinction took placehellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and airB Water and airC Land and airD Water and land
9 Iridium ishellip
A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction
Solution
1 B
2 A
3 C
4 D
5 A
6 C
7 B
8 D
9 A
10 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 1 of 15
Mass extinctions
A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major
mass extinction events in Earths history
These are shown in the table given along with the major events that characterised each
Learn about the five major mass extinctions that occurred in Earths history
Video 2CY4
Five of the following extinction events are recognised (listed from the most recent at top of the list to the
earliest oldest at bottom of list
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
bull End-Triassic
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull Late Devonian
bull Late Ordovician
Major mass extinction event
Date of occurrence
Major events
Cretaceous-Paleogene extinction event
65 million years ago
Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates
Triassic-Jurassic event
205 million years ago
Most non-dinosaur species were eliminated leaving land dinosaurs with no competition
Permian-Triassic event
250 million years ago
This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection
Late Devonian extinction
375ndash360 million years ago
This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated
Ordovician-Silurian extinction event
450ndash440 million years ago
Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 2 of 15
Causes of mass extinctions (ESGCW)
Watch a video about the debate about what really killed the dinosaurs
Video 2CY6
There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory
to explain what caused mass extinctions the theory must
bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg
dinosaurs)
bull Explain why some organisms died and others survived
bull Be based on natural events and processes that are shown to have occurred around the time of
extinction
Two of the hypotheses put forward are
bull the impact theory of extinction
bull massive volcanic activity
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 3 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 4 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 5 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 6 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Mass Extinctions
Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists
Remember that there are two types of extinctions
They are natural and man made extinctions
Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed
But there are times when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years
This is called a mass extinction
What are they
The Five Major Mass Extinctions
The earliest known mass extinction occurred about 439 million years ago and was caused by a drop in sea levels
The sea levels dropped because of the formation of glaciers
The sea levels rises as the glaciers started to melt
The first mass extinction
The Five Major Mass Extinctions
The second extinction occurred about 364 million years agoIt is not known what caused this extinction
The third extinction occurred about 250 million years agoIt may have been caused by comet or asteroid impact or volcanic floods
The second and third mass extinction
The Five Major Mass Extinctions
The fourth mass extinction occurred about 199 million to 214 million years ago
It was caused when volcanoes erupted releasing large amounts of lava
This is turn lead to global warming
The fourth mass extinction
The Five Major Mass Extinctions
The fifth mass extinction occurred about 65 million years ago
There are several possible causesbull asteroid impact on the Yucatan Peninsula which is in
the Gulf of Mexicobull gradual climate changebull volcanic eruptions
The fifth mass extinction
Two Particular Extinctions
Of the five mass extinctions two stand out
These were the one that occurred 250 million years ago and the one that occurred 65 million years ago
The mass extinction that occurred 250 million years ago was the most serious one
The most famous mass extinction occurred 65 million years ago the extinction of the dinosaurs
Two Particular Extinctions
During this extinction almost 90 all species became extinct
This included 84 of marine genera and about 70 of land species plants insects and vertebrate animals
The mass extinction of 250 million years ago
Two Particular Extinctions
The dinosaurs appeared about 245 million years ago
They flourished during the Jurassic Period
This period occurred about 208 to 143 million years ago
The dinosaurs dominated the land and air and some of them even lived in water
Two Particular Extinctions
Birds and mammals also existed during this time
The dinosaurs then became extinct in a short period of 10 million years
This occurred about 65 million years ago
Of the marine families 16 marine genera 47 and 18 of the land vertebrate families also became extinct during this time
The mass extinction of 65 million years ago
Two Particular Extinctions
Scientists are not sure about the exact cause of this mass extinction
However the following are some of the conditions that occurred during this timeo there was a sharp drop in temperatureo the water of the seas evaporates
The mass extinction of 65 million years - Causes
Two Particular Extinctions
Many of the plants the source of food for the dinosaurs died out
Iridium was found in a thin layer of clay
Iridium is an element that is very rare on earth but common in meteorites
A huge crater was found in the Caribbean Sea
There were many volcanic eruptions in India
The mass extinction of 65 million years - Causes
Two Particular Extinctions
The above evidence lead to the formation of three hypothesis
The most common hypothesis is that an asteroid crashed onto Earth causing global climate change
The climate change lead to the mass extinction
The layer of iridium and the large crater in the Caribbean sea support this hypothesis
The mass extinction of 65 million years ago - Hypothesis
Two Particular Extinctions
This hypothesis deals with the continental drift theory movement of continents away from each other
It is believed that the continental drift led to the climate change
The mass extinction of 65 million years ago- Hypothesis 2
Two Particular Extinctions
This hypothesis deals with the volcanic activity in India
It is believed that this volcanic activity released particles into the air
These particles blocked out the sun for a long period of time
This resulted in the lowering of temperatures on Earth
Therefore many species died out because they could not adapt to the low temperature
The mass extinction of 65 million years ago ndash Hypothesis 3
Two Particular Extinctions
Scientists accept all three theories
Mass extinction was caused by climate change
The climate change was caused by the asteroid impact and volcanic activity
The mass extinction of 65 million years
The Holocene Epoch
The next major extinction is occurring presently
This is the sixth mass extinction
Human exploitation of the environment is the cause of this mass extinction
It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction
Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time
The sixth major extinction
Terminology
Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists
Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed
Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years
Jurassic Period period when dinosaurs flourished
Something for you to do
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
4 The first mass extinction was caused byhellip
A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above
5 The most famous extinction took placehellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and airB Water and airC Land and airD Water and land
9 Iridium ishellip
A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction
Solution
1 B
2 A
3 C
4 D
5 A
6 C
7 B
8 D
9 A
10 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 1 of 15
Mass extinctions
A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major
mass extinction events in Earths history
These are shown in the table given along with the major events that characterised each
Learn about the five major mass extinctions that occurred in Earths history
Video 2CY4
Five of the following extinction events are recognised (listed from the most recent at top of the list to the
earliest oldest at bottom of list
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
bull End-Triassic
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull Late Devonian
bull Late Ordovician
Major mass extinction event
Date of occurrence
Major events
Cretaceous-Paleogene extinction event
65 million years ago
Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates
Triassic-Jurassic event
205 million years ago
Most non-dinosaur species were eliminated leaving land dinosaurs with no competition
Permian-Triassic event
250 million years ago
This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection
Late Devonian extinction
375ndash360 million years ago
This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated
Ordovician-Silurian extinction event
450ndash440 million years ago
Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 2 of 15
Causes of mass extinctions (ESGCW)
Watch a video about the debate about what really killed the dinosaurs
Video 2CY6
There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory
to explain what caused mass extinctions the theory must
bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg
dinosaurs)
bull Explain why some organisms died and others survived
bull Be based on natural events and processes that are shown to have occurred around the time of
extinction
Two of the hypotheses put forward are
bull the impact theory of extinction
bull massive volcanic activity
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 3 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 4 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 5 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
The Five Major Mass Extinctions
The earliest known mass extinction occurred about 439 million years ago and was caused by a drop in sea levels
The sea levels dropped because of the formation of glaciers
The sea levels rises as the glaciers started to melt
The first mass extinction
The Five Major Mass Extinctions
The second extinction occurred about 364 million years agoIt is not known what caused this extinction
The third extinction occurred about 250 million years agoIt may have been caused by comet or asteroid impact or volcanic floods
The second and third mass extinction
The Five Major Mass Extinctions
The fourth mass extinction occurred about 199 million to 214 million years ago
It was caused when volcanoes erupted releasing large amounts of lava
This is turn lead to global warming
The fourth mass extinction
The Five Major Mass Extinctions
The fifth mass extinction occurred about 65 million years ago
There are several possible causesbull asteroid impact on the Yucatan Peninsula which is in
the Gulf of Mexicobull gradual climate changebull volcanic eruptions
The fifth mass extinction
Two Particular Extinctions
Of the five mass extinctions two stand out
These were the one that occurred 250 million years ago and the one that occurred 65 million years ago
The mass extinction that occurred 250 million years ago was the most serious one
The most famous mass extinction occurred 65 million years ago the extinction of the dinosaurs
Two Particular Extinctions
During this extinction almost 90 all species became extinct
This included 84 of marine genera and about 70 of land species plants insects and vertebrate animals
The mass extinction of 250 million years ago
Two Particular Extinctions
The dinosaurs appeared about 245 million years ago
They flourished during the Jurassic Period
This period occurred about 208 to 143 million years ago
The dinosaurs dominated the land and air and some of them even lived in water
Two Particular Extinctions
Birds and mammals also existed during this time
The dinosaurs then became extinct in a short period of 10 million years
This occurred about 65 million years ago
Of the marine families 16 marine genera 47 and 18 of the land vertebrate families also became extinct during this time
The mass extinction of 65 million years ago
Two Particular Extinctions
Scientists are not sure about the exact cause of this mass extinction
However the following are some of the conditions that occurred during this timeo there was a sharp drop in temperatureo the water of the seas evaporates
The mass extinction of 65 million years - Causes
Two Particular Extinctions
Many of the plants the source of food for the dinosaurs died out
Iridium was found in a thin layer of clay
Iridium is an element that is very rare on earth but common in meteorites
A huge crater was found in the Caribbean Sea
There were many volcanic eruptions in India
The mass extinction of 65 million years - Causes
Two Particular Extinctions
The above evidence lead to the formation of three hypothesis
The most common hypothesis is that an asteroid crashed onto Earth causing global climate change
The climate change lead to the mass extinction
The layer of iridium and the large crater in the Caribbean sea support this hypothesis
The mass extinction of 65 million years ago - Hypothesis
Two Particular Extinctions
This hypothesis deals with the continental drift theory movement of continents away from each other
It is believed that the continental drift led to the climate change
The mass extinction of 65 million years ago- Hypothesis 2
Two Particular Extinctions
This hypothesis deals with the volcanic activity in India
It is believed that this volcanic activity released particles into the air
These particles blocked out the sun for a long period of time
This resulted in the lowering of temperatures on Earth
Therefore many species died out because they could not adapt to the low temperature
The mass extinction of 65 million years ago ndash Hypothesis 3
Two Particular Extinctions
Scientists accept all three theories
Mass extinction was caused by climate change
The climate change was caused by the asteroid impact and volcanic activity
The mass extinction of 65 million years
The Holocene Epoch
The next major extinction is occurring presently
This is the sixth mass extinction
Human exploitation of the environment is the cause of this mass extinction
It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction
Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time
The sixth major extinction
Terminology
Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists
Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed
Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years
Jurassic Period period when dinosaurs flourished
Something for you to do
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
4 The first mass extinction was caused byhellip
A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above
5 The most famous extinction took placehellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and airB Water and airC Land and airD Water and land
9 Iridium ishellip
A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction
Solution
1 B
2 A
3 C
4 D
5 A
6 C
7 B
8 D
9 A
10 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 1 of 15
Mass extinctions
A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major
mass extinction events in Earths history
These are shown in the table given along with the major events that characterised each
Learn about the five major mass extinctions that occurred in Earths history
Video 2CY4
Five of the following extinction events are recognised (listed from the most recent at top of the list to the
earliest oldest at bottom of list
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
bull End-Triassic
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull Late Devonian
bull Late Ordovician
Major mass extinction event
Date of occurrence
Major events
Cretaceous-Paleogene extinction event
65 million years ago
Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates
Triassic-Jurassic event
205 million years ago
Most non-dinosaur species were eliminated leaving land dinosaurs with no competition
Permian-Triassic event
250 million years ago
This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection
Late Devonian extinction
375ndash360 million years ago
This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated
Ordovician-Silurian extinction event
450ndash440 million years ago
Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 2 of 15
Causes of mass extinctions (ESGCW)
Watch a video about the debate about what really killed the dinosaurs
Video 2CY6
There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory
to explain what caused mass extinctions the theory must
bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg
dinosaurs)
bull Explain why some organisms died and others survived
bull Be based on natural events and processes that are shown to have occurred around the time of
extinction
Two of the hypotheses put forward are
bull the impact theory of extinction
bull massive volcanic activity
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 3 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 5 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 6 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
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travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
The Five Major Mass Extinctions
The second extinction occurred about 364 million years agoIt is not known what caused this extinction
The third extinction occurred about 250 million years agoIt may have been caused by comet or asteroid impact or volcanic floods
The second and third mass extinction
The Five Major Mass Extinctions
The fourth mass extinction occurred about 199 million to 214 million years ago
It was caused when volcanoes erupted releasing large amounts of lava
This is turn lead to global warming
The fourth mass extinction
The Five Major Mass Extinctions
The fifth mass extinction occurred about 65 million years ago
There are several possible causesbull asteroid impact on the Yucatan Peninsula which is in
the Gulf of Mexicobull gradual climate changebull volcanic eruptions
The fifth mass extinction
Two Particular Extinctions
Of the five mass extinctions two stand out
These were the one that occurred 250 million years ago and the one that occurred 65 million years ago
The mass extinction that occurred 250 million years ago was the most serious one
The most famous mass extinction occurred 65 million years ago the extinction of the dinosaurs
Two Particular Extinctions
During this extinction almost 90 all species became extinct
This included 84 of marine genera and about 70 of land species plants insects and vertebrate animals
The mass extinction of 250 million years ago
Two Particular Extinctions
The dinosaurs appeared about 245 million years ago
They flourished during the Jurassic Period
This period occurred about 208 to 143 million years ago
The dinosaurs dominated the land and air and some of them even lived in water
Two Particular Extinctions
Birds and mammals also existed during this time
The dinosaurs then became extinct in a short period of 10 million years
This occurred about 65 million years ago
Of the marine families 16 marine genera 47 and 18 of the land vertebrate families also became extinct during this time
The mass extinction of 65 million years ago
Two Particular Extinctions
Scientists are not sure about the exact cause of this mass extinction
However the following are some of the conditions that occurred during this timeo there was a sharp drop in temperatureo the water of the seas evaporates
The mass extinction of 65 million years - Causes
Two Particular Extinctions
Many of the plants the source of food for the dinosaurs died out
Iridium was found in a thin layer of clay
Iridium is an element that is very rare on earth but common in meteorites
A huge crater was found in the Caribbean Sea
There were many volcanic eruptions in India
The mass extinction of 65 million years - Causes
Two Particular Extinctions
The above evidence lead to the formation of three hypothesis
The most common hypothesis is that an asteroid crashed onto Earth causing global climate change
The climate change lead to the mass extinction
The layer of iridium and the large crater in the Caribbean sea support this hypothesis
The mass extinction of 65 million years ago - Hypothesis
Two Particular Extinctions
This hypothesis deals with the continental drift theory movement of continents away from each other
It is believed that the continental drift led to the climate change
The mass extinction of 65 million years ago- Hypothesis 2
Two Particular Extinctions
This hypothesis deals with the volcanic activity in India
It is believed that this volcanic activity released particles into the air
These particles blocked out the sun for a long period of time
This resulted in the lowering of temperatures on Earth
Therefore many species died out because they could not adapt to the low temperature
The mass extinction of 65 million years ago ndash Hypothesis 3
Two Particular Extinctions
Scientists accept all three theories
Mass extinction was caused by climate change
The climate change was caused by the asteroid impact and volcanic activity
The mass extinction of 65 million years
The Holocene Epoch
The next major extinction is occurring presently
This is the sixth mass extinction
Human exploitation of the environment is the cause of this mass extinction
It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction
Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time
The sixth major extinction
Terminology
Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists
Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed
Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years
Jurassic Period period when dinosaurs flourished
Something for you to do
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
4 The first mass extinction was caused byhellip
A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above
5 The most famous extinction took placehellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and airB Water and airC Land and airD Water and land
9 Iridium ishellip
A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction
Solution
1 B
2 A
3 C
4 D
5 A
6 C
7 B
8 D
9 A
10 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 1 of 15
Mass extinctions
A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major
mass extinction events in Earths history
These are shown in the table given along with the major events that characterised each
Learn about the five major mass extinctions that occurred in Earths history
Video 2CY4
Five of the following extinction events are recognised (listed from the most recent at top of the list to the
earliest oldest at bottom of list
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
bull End-Triassic
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull Late Devonian
bull Late Ordovician
Major mass extinction event
Date of occurrence
Major events
Cretaceous-Paleogene extinction event
65 million years ago
Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates
Triassic-Jurassic event
205 million years ago
Most non-dinosaur species were eliminated leaving land dinosaurs with no competition
Permian-Triassic event
250 million years ago
This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection
Late Devonian extinction
375ndash360 million years ago
This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated
Ordovician-Silurian extinction event
450ndash440 million years ago
Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 2 of 15
Causes of mass extinctions (ESGCW)
Watch a video about the debate about what really killed the dinosaurs
Video 2CY6
There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory
to explain what caused mass extinctions the theory must
bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg
dinosaurs)
bull Explain why some organisms died and others survived
bull Be based on natural events and processes that are shown to have occurred around the time of
extinction
Two of the hypotheses put forward are
bull the impact theory of extinction
bull massive volcanic activity
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 3 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 4 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 5 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 6 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
The Five Major Mass Extinctions
The fourth mass extinction occurred about 199 million to 214 million years ago
It was caused when volcanoes erupted releasing large amounts of lava
This is turn lead to global warming
The fourth mass extinction
The Five Major Mass Extinctions
The fifth mass extinction occurred about 65 million years ago
There are several possible causesbull asteroid impact on the Yucatan Peninsula which is in
the Gulf of Mexicobull gradual climate changebull volcanic eruptions
The fifth mass extinction
Two Particular Extinctions
Of the five mass extinctions two stand out
These were the one that occurred 250 million years ago and the one that occurred 65 million years ago
The mass extinction that occurred 250 million years ago was the most serious one
The most famous mass extinction occurred 65 million years ago the extinction of the dinosaurs
Two Particular Extinctions
During this extinction almost 90 all species became extinct
This included 84 of marine genera and about 70 of land species plants insects and vertebrate animals
The mass extinction of 250 million years ago
Two Particular Extinctions
The dinosaurs appeared about 245 million years ago
They flourished during the Jurassic Period
This period occurred about 208 to 143 million years ago
The dinosaurs dominated the land and air and some of them even lived in water
Two Particular Extinctions
Birds and mammals also existed during this time
The dinosaurs then became extinct in a short period of 10 million years
This occurred about 65 million years ago
Of the marine families 16 marine genera 47 and 18 of the land vertebrate families also became extinct during this time
The mass extinction of 65 million years ago
Two Particular Extinctions
Scientists are not sure about the exact cause of this mass extinction
However the following are some of the conditions that occurred during this timeo there was a sharp drop in temperatureo the water of the seas evaporates
The mass extinction of 65 million years - Causes
Two Particular Extinctions
Many of the plants the source of food for the dinosaurs died out
Iridium was found in a thin layer of clay
Iridium is an element that is very rare on earth but common in meteorites
A huge crater was found in the Caribbean Sea
There were many volcanic eruptions in India
The mass extinction of 65 million years - Causes
Two Particular Extinctions
The above evidence lead to the formation of three hypothesis
The most common hypothesis is that an asteroid crashed onto Earth causing global climate change
The climate change lead to the mass extinction
The layer of iridium and the large crater in the Caribbean sea support this hypothesis
The mass extinction of 65 million years ago - Hypothesis
Two Particular Extinctions
This hypothesis deals with the continental drift theory movement of continents away from each other
It is believed that the continental drift led to the climate change
The mass extinction of 65 million years ago- Hypothesis 2
Two Particular Extinctions
This hypothesis deals with the volcanic activity in India
It is believed that this volcanic activity released particles into the air
These particles blocked out the sun for a long period of time
This resulted in the lowering of temperatures on Earth
Therefore many species died out because they could not adapt to the low temperature
The mass extinction of 65 million years ago ndash Hypothesis 3
Two Particular Extinctions
Scientists accept all three theories
Mass extinction was caused by climate change
The climate change was caused by the asteroid impact and volcanic activity
The mass extinction of 65 million years
The Holocene Epoch
The next major extinction is occurring presently
This is the sixth mass extinction
Human exploitation of the environment is the cause of this mass extinction
It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction
Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time
The sixth major extinction
Terminology
Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists
Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed
Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years
Jurassic Period period when dinosaurs flourished
Something for you to do
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
4 The first mass extinction was caused byhellip
A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above
5 The most famous extinction took placehellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and airB Water and airC Land and airD Water and land
9 Iridium ishellip
A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction
Solution
1 B
2 A
3 C
4 D
5 A
6 C
7 B
8 D
9 A
10 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 1 of 15
Mass extinctions
A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major
mass extinction events in Earths history
These are shown in the table given along with the major events that characterised each
Learn about the five major mass extinctions that occurred in Earths history
Video 2CY4
Five of the following extinction events are recognised (listed from the most recent at top of the list to the
earliest oldest at bottom of list
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
bull End-Triassic
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull Late Devonian
bull Late Ordovician
Major mass extinction event
Date of occurrence
Major events
Cretaceous-Paleogene extinction event
65 million years ago
Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates
Triassic-Jurassic event
205 million years ago
Most non-dinosaur species were eliminated leaving land dinosaurs with no competition
Permian-Triassic event
250 million years ago
This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection
Late Devonian extinction
375ndash360 million years ago
This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated
Ordovician-Silurian extinction event
450ndash440 million years ago
Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 2 of 15
Causes of mass extinctions (ESGCW)
Watch a video about the debate about what really killed the dinosaurs
Video 2CY6
There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory
to explain what caused mass extinctions the theory must
bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg
dinosaurs)
bull Explain why some organisms died and others survived
bull Be based on natural events and processes that are shown to have occurred around the time of
extinction
Two of the hypotheses put forward are
bull the impact theory of extinction
bull massive volcanic activity
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 3 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 4 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 5 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 6 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
The Five Major Mass Extinctions
The fifth mass extinction occurred about 65 million years ago
There are several possible causesbull asteroid impact on the Yucatan Peninsula which is in
the Gulf of Mexicobull gradual climate changebull volcanic eruptions
The fifth mass extinction
Two Particular Extinctions
Of the five mass extinctions two stand out
These were the one that occurred 250 million years ago and the one that occurred 65 million years ago
The mass extinction that occurred 250 million years ago was the most serious one
The most famous mass extinction occurred 65 million years ago the extinction of the dinosaurs
Two Particular Extinctions
During this extinction almost 90 all species became extinct
This included 84 of marine genera and about 70 of land species plants insects and vertebrate animals
The mass extinction of 250 million years ago
Two Particular Extinctions
The dinosaurs appeared about 245 million years ago
They flourished during the Jurassic Period
This period occurred about 208 to 143 million years ago
The dinosaurs dominated the land and air and some of them even lived in water
Two Particular Extinctions
Birds and mammals also existed during this time
The dinosaurs then became extinct in a short period of 10 million years
This occurred about 65 million years ago
Of the marine families 16 marine genera 47 and 18 of the land vertebrate families also became extinct during this time
The mass extinction of 65 million years ago
Two Particular Extinctions
Scientists are not sure about the exact cause of this mass extinction
However the following are some of the conditions that occurred during this timeo there was a sharp drop in temperatureo the water of the seas evaporates
The mass extinction of 65 million years - Causes
Two Particular Extinctions
Many of the plants the source of food for the dinosaurs died out
Iridium was found in a thin layer of clay
Iridium is an element that is very rare on earth but common in meteorites
A huge crater was found in the Caribbean Sea
There were many volcanic eruptions in India
The mass extinction of 65 million years - Causes
Two Particular Extinctions
The above evidence lead to the formation of three hypothesis
The most common hypothesis is that an asteroid crashed onto Earth causing global climate change
The climate change lead to the mass extinction
The layer of iridium and the large crater in the Caribbean sea support this hypothesis
The mass extinction of 65 million years ago - Hypothesis
Two Particular Extinctions
This hypothesis deals with the continental drift theory movement of continents away from each other
It is believed that the continental drift led to the climate change
The mass extinction of 65 million years ago- Hypothesis 2
Two Particular Extinctions
This hypothesis deals with the volcanic activity in India
It is believed that this volcanic activity released particles into the air
These particles blocked out the sun for a long period of time
This resulted in the lowering of temperatures on Earth
Therefore many species died out because they could not adapt to the low temperature
The mass extinction of 65 million years ago ndash Hypothesis 3
Two Particular Extinctions
Scientists accept all three theories
Mass extinction was caused by climate change
The climate change was caused by the asteroid impact and volcanic activity
The mass extinction of 65 million years
The Holocene Epoch
The next major extinction is occurring presently
This is the sixth mass extinction
Human exploitation of the environment is the cause of this mass extinction
It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction
Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time
The sixth major extinction
Terminology
Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists
Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed
Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years
Jurassic Period period when dinosaurs flourished
Something for you to do
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
4 The first mass extinction was caused byhellip
A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above
5 The most famous extinction took placehellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and airB Water and airC Land and airD Water and land
9 Iridium ishellip
A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction
Solution
1 B
2 A
3 C
4 D
5 A
6 C
7 B
8 D
9 A
10 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 1 of 15
Mass extinctions
A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major
mass extinction events in Earths history
These are shown in the table given along with the major events that characterised each
Learn about the five major mass extinctions that occurred in Earths history
Video 2CY4
Five of the following extinction events are recognised (listed from the most recent at top of the list to the
earliest oldest at bottom of list
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
bull End-Triassic
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull Late Devonian
bull Late Ordovician
Major mass extinction event
Date of occurrence
Major events
Cretaceous-Paleogene extinction event
65 million years ago
Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates
Triassic-Jurassic event
205 million years ago
Most non-dinosaur species were eliminated leaving land dinosaurs with no competition
Permian-Triassic event
250 million years ago
This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection
Late Devonian extinction
375ndash360 million years ago
This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated
Ordovician-Silurian extinction event
450ndash440 million years ago
Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 2 of 15
Causes of mass extinctions (ESGCW)
Watch a video about the debate about what really killed the dinosaurs
Video 2CY6
There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory
to explain what caused mass extinctions the theory must
bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg
dinosaurs)
bull Explain why some organisms died and others survived
bull Be based on natural events and processes that are shown to have occurred around the time of
extinction
Two of the hypotheses put forward are
bull the impact theory of extinction
bull massive volcanic activity
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 3 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 4 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 5 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 6 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 7 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Two Particular Extinctions
Of the five mass extinctions two stand out
These were the one that occurred 250 million years ago and the one that occurred 65 million years ago
The mass extinction that occurred 250 million years ago was the most serious one
The most famous mass extinction occurred 65 million years ago the extinction of the dinosaurs
Two Particular Extinctions
During this extinction almost 90 all species became extinct
This included 84 of marine genera and about 70 of land species plants insects and vertebrate animals
The mass extinction of 250 million years ago
Two Particular Extinctions
The dinosaurs appeared about 245 million years ago
They flourished during the Jurassic Period
This period occurred about 208 to 143 million years ago
The dinosaurs dominated the land and air and some of them even lived in water
Two Particular Extinctions
Birds and mammals also existed during this time
The dinosaurs then became extinct in a short period of 10 million years
This occurred about 65 million years ago
Of the marine families 16 marine genera 47 and 18 of the land vertebrate families also became extinct during this time
The mass extinction of 65 million years ago
Two Particular Extinctions
Scientists are not sure about the exact cause of this mass extinction
However the following are some of the conditions that occurred during this timeo there was a sharp drop in temperatureo the water of the seas evaporates
The mass extinction of 65 million years - Causes
Two Particular Extinctions
Many of the plants the source of food for the dinosaurs died out
Iridium was found in a thin layer of clay
Iridium is an element that is very rare on earth but common in meteorites
A huge crater was found in the Caribbean Sea
There were many volcanic eruptions in India
The mass extinction of 65 million years - Causes
Two Particular Extinctions
The above evidence lead to the formation of three hypothesis
The most common hypothesis is that an asteroid crashed onto Earth causing global climate change
The climate change lead to the mass extinction
The layer of iridium and the large crater in the Caribbean sea support this hypothesis
The mass extinction of 65 million years ago - Hypothesis
Two Particular Extinctions
This hypothesis deals with the continental drift theory movement of continents away from each other
It is believed that the continental drift led to the climate change
The mass extinction of 65 million years ago- Hypothesis 2
Two Particular Extinctions
This hypothesis deals with the volcanic activity in India
It is believed that this volcanic activity released particles into the air
These particles blocked out the sun for a long period of time
This resulted in the lowering of temperatures on Earth
Therefore many species died out because they could not adapt to the low temperature
The mass extinction of 65 million years ago ndash Hypothesis 3
Two Particular Extinctions
Scientists accept all three theories
Mass extinction was caused by climate change
The climate change was caused by the asteroid impact and volcanic activity
The mass extinction of 65 million years
The Holocene Epoch
The next major extinction is occurring presently
This is the sixth mass extinction
Human exploitation of the environment is the cause of this mass extinction
It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction
Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time
The sixth major extinction
Terminology
Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists
Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed
Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years
Jurassic Period period when dinosaurs flourished
Something for you to do
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
4 The first mass extinction was caused byhellip
A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above
5 The most famous extinction took placehellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and airB Water and airC Land and airD Water and land
9 Iridium ishellip
A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction
Solution
1 B
2 A
3 C
4 D
5 A
6 C
7 B
8 D
9 A
10 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 1 of 15
Mass extinctions
A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major
mass extinction events in Earths history
These are shown in the table given along with the major events that characterised each
Learn about the five major mass extinctions that occurred in Earths history
Video 2CY4
Five of the following extinction events are recognised (listed from the most recent at top of the list to the
earliest oldest at bottom of list
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
bull End-Triassic
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull Late Devonian
bull Late Ordovician
Major mass extinction event
Date of occurrence
Major events
Cretaceous-Paleogene extinction event
65 million years ago
Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates
Triassic-Jurassic event
205 million years ago
Most non-dinosaur species were eliminated leaving land dinosaurs with no competition
Permian-Triassic event
250 million years ago
This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection
Late Devonian extinction
375ndash360 million years ago
This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated
Ordovician-Silurian extinction event
450ndash440 million years ago
Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 2 of 15
Causes of mass extinctions (ESGCW)
Watch a video about the debate about what really killed the dinosaurs
Video 2CY6
There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory
to explain what caused mass extinctions the theory must
bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg
dinosaurs)
bull Explain why some organisms died and others survived
bull Be based on natural events and processes that are shown to have occurred around the time of
extinction
Two of the hypotheses put forward are
bull the impact theory of extinction
bull massive volcanic activity
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 3 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 4 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 5 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 6 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Two Particular Extinctions
During this extinction almost 90 all species became extinct
This included 84 of marine genera and about 70 of land species plants insects and vertebrate animals
The mass extinction of 250 million years ago
Two Particular Extinctions
The dinosaurs appeared about 245 million years ago
They flourished during the Jurassic Period
This period occurred about 208 to 143 million years ago
The dinosaurs dominated the land and air and some of them even lived in water
Two Particular Extinctions
Birds and mammals also existed during this time
The dinosaurs then became extinct in a short period of 10 million years
This occurred about 65 million years ago
Of the marine families 16 marine genera 47 and 18 of the land vertebrate families also became extinct during this time
The mass extinction of 65 million years ago
Two Particular Extinctions
Scientists are not sure about the exact cause of this mass extinction
However the following are some of the conditions that occurred during this timeo there was a sharp drop in temperatureo the water of the seas evaporates
The mass extinction of 65 million years - Causes
Two Particular Extinctions
Many of the plants the source of food for the dinosaurs died out
Iridium was found in a thin layer of clay
Iridium is an element that is very rare on earth but common in meteorites
A huge crater was found in the Caribbean Sea
There were many volcanic eruptions in India
The mass extinction of 65 million years - Causes
Two Particular Extinctions
The above evidence lead to the formation of three hypothesis
The most common hypothesis is that an asteroid crashed onto Earth causing global climate change
The climate change lead to the mass extinction
The layer of iridium and the large crater in the Caribbean sea support this hypothesis
The mass extinction of 65 million years ago - Hypothesis
Two Particular Extinctions
This hypothesis deals with the continental drift theory movement of continents away from each other
It is believed that the continental drift led to the climate change
The mass extinction of 65 million years ago- Hypothesis 2
Two Particular Extinctions
This hypothesis deals with the volcanic activity in India
It is believed that this volcanic activity released particles into the air
These particles blocked out the sun for a long period of time
This resulted in the lowering of temperatures on Earth
Therefore many species died out because they could not adapt to the low temperature
The mass extinction of 65 million years ago ndash Hypothesis 3
Two Particular Extinctions
Scientists accept all three theories
Mass extinction was caused by climate change
The climate change was caused by the asteroid impact and volcanic activity
The mass extinction of 65 million years
The Holocene Epoch
The next major extinction is occurring presently
This is the sixth mass extinction
Human exploitation of the environment is the cause of this mass extinction
It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction
Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time
The sixth major extinction
Terminology
Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists
Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed
Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years
Jurassic Period period when dinosaurs flourished
Something for you to do
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
4 The first mass extinction was caused byhellip
A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above
5 The most famous extinction took placehellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and airB Water and airC Land and airD Water and land
9 Iridium ishellip
A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction
Solution
1 B
2 A
3 C
4 D
5 A
6 C
7 B
8 D
9 A
10 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 1 of 15
Mass extinctions
A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major
mass extinction events in Earths history
These are shown in the table given along with the major events that characterised each
Learn about the five major mass extinctions that occurred in Earths history
Video 2CY4
Five of the following extinction events are recognised (listed from the most recent at top of the list to the
earliest oldest at bottom of list
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
bull End-Triassic
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull Late Devonian
bull Late Ordovician
Major mass extinction event
Date of occurrence
Major events
Cretaceous-Paleogene extinction event
65 million years ago
Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates
Triassic-Jurassic event
205 million years ago
Most non-dinosaur species were eliminated leaving land dinosaurs with no competition
Permian-Triassic event
250 million years ago
This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection
Late Devonian extinction
375ndash360 million years ago
This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated
Ordovician-Silurian extinction event
450ndash440 million years ago
Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 2 of 15
Causes of mass extinctions (ESGCW)
Watch a video about the debate about what really killed the dinosaurs
Video 2CY6
There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory
to explain what caused mass extinctions the theory must
bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg
dinosaurs)
bull Explain why some organisms died and others survived
bull Be based on natural events and processes that are shown to have occurred around the time of
extinction
Two of the hypotheses put forward are
bull the impact theory of extinction
bull massive volcanic activity
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 3 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Two Particular Extinctions
The dinosaurs appeared about 245 million years ago
They flourished during the Jurassic Period
This period occurred about 208 to 143 million years ago
The dinosaurs dominated the land and air and some of them even lived in water
Two Particular Extinctions
Birds and mammals also existed during this time
The dinosaurs then became extinct in a short period of 10 million years
This occurred about 65 million years ago
Of the marine families 16 marine genera 47 and 18 of the land vertebrate families also became extinct during this time
The mass extinction of 65 million years ago
Two Particular Extinctions
Scientists are not sure about the exact cause of this mass extinction
However the following are some of the conditions that occurred during this timeo there was a sharp drop in temperatureo the water of the seas evaporates
The mass extinction of 65 million years - Causes
Two Particular Extinctions
Many of the plants the source of food for the dinosaurs died out
Iridium was found in a thin layer of clay
Iridium is an element that is very rare on earth but common in meteorites
A huge crater was found in the Caribbean Sea
There were many volcanic eruptions in India
The mass extinction of 65 million years - Causes
Two Particular Extinctions
The above evidence lead to the formation of three hypothesis
The most common hypothesis is that an asteroid crashed onto Earth causing global climate change
The climate change lead to the mass extinction
The layer of iridium and the large crater in the Caribbean sea support this hypothesis
The mass extinction of 65 million years ago - Hypothesis
Two Particular Extinctions
This hypothesis deals with the continental drift theory movement of continents away from each other
It is believed that the continental drift led to the climate change
The mass extinction of 65 million years ago- Hypothesis 2
Two Particular Extinctions
This hypothesis deals with the volcanic activity in India
It is believed that this volcanic activity released particles into the air
These particles blocked out the sun for a long period of time
This resulted in the lowering of temperatures on Earth
Therefore many species died out because they could not adapt to the low temperature
The mass extinction of 65 million years ago ndash Hypothesis 3
Two Particular Extinctions
Scientists accept all three theories
Mass extinction was caused by climate change
The climate change was caused by the asteroid impact and volcanic activity
The mass extinction of 65 million years
The Holocene Epoch
The next major extinction is occurring presently
This is the sixth mass extinction
Human exploitation of the environment is the cause of this mass extinction
It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction
Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time
The sixth major extinction
Terminology
Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists
Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed
Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years
Jurassic Period period when dinosaurs flourished
Something for you to do
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
4 The first mass extinction was caused byhellip
A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above
5 The most famous extinction took placehellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and airB Water and airC Land and airD Water and land
9 Iridium ishellip
A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction
Solution
1 B
2 A
3 C
4 D
5 A
6 C
7 B
8 D
9 A
10 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 1 of 15
Mass extinctions
A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major
mass extinction events in Earths history
These are shown in the table given along with the major events that characterised each
Learn about the five major mass extinctions that occurred in Earths history
Video 2CY4
Five of the following extinction events are recognised (listed from the most recent at top of the list to the
earliest oldest at bottom of list
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
bull End-Triassic
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull Late Devonian
bull Late Ordovician
Major mass extinction event
Date of occurrence
Major events
Cretaceous-Paleogene extinction event
65 million years ago
Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates
Triassic-Jurassic event
205 million years ago
Most non-dinosaur species were eliminated leaving land dinosaurs with no competition
Permian-Triassic event
250 million years ago
This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection
Late Devonian extinction
375ndash360 million years ago
This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated
Ordovician-Silurian extinction event
450ndash440 million years ago
Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 2 of 15
Causes of mass extinctions (ESGCW)
Watch a video about the debate about what really killed the dinosaurs
Video 2CY6
There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory
to explain what caused mass extinctions the theory must
bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg
dinosaurs)
bull Explain why some organisms died and others survived
bull Be based on natural events and processes that are shown to have occurred around the time of
extinction
Two of the hypotheses put forward are
bull the impact theory of extinction
bull massive volcanic activity
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 3 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 4 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 5 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 6 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Two Particular Extinctions
Birds and mammals also existed during this time
The dinosaurs then became extinct in a short period of 10 million years
This occurred about 65 million years ago
Of the marine families 16 marine genera 47 and 18 of the land vertebrate families also became extinct during this time
The mass extinction of 65 million years ago
Two Particular Extinctions
Scientists are not sure about the exact cause of this mass extinction
However the following are some of the conditions that occurred during this timeo there was a sharp drop in temperatureo the water of the seas evaporates
The mass extinction of 65 million years - Causes
Two Particular Extinctions
Many of the plants the source of food for the dinosaurs died out
Iridium was found in a thin layer of clay
Iridium is an element that is very rare on earth but common in meteorites
A huge crater was found in the Caribbean Sea
There were many volcanic eruptions in India
The mass extinction of 65 million years - Causes
Two Particular Extinctions
The above evidence lead to the formation of three hypothesis
The most common hypothesis is that an asteroid crashed onto Earth causing global climate change
The climate change lead to the mass extinction
The layer of iridium and the large crater in the Caribbean sea support this hypothesis
The mass extinction of 65 million years ago - Hypothesis
Two Particular Extinctions
This hypothesis deals with the continental drift theory movement of continents away from each other
It is believed that the continental drift led to the climate change
The mass extinction of 65 million years ago- Hypothesis 2
Two Particular Extinctions
This hypothesis deals with the volcanic activity in India
It is believed that this volcanic activity released particles into the air
These particles blocked out the sun for a long period of time
This resulted in the lowering of temperatures on Earth
Therefore many species died out because they could not adapt to the low temperature
The mass extinction of 65 million years ago ndash Hypothesis 3
Two Particular Extinctions
Scientists accept all three theories
Mass extinction was caused by climate change
The climate change was caused by the asteroid impact and volcanic activity
The mass extinction of 65 million years
The Holocene Epoch
The next major extinction is occurring presently
This is the sixth mass extinction
Human exploitation of the environment is the cause of this mass extinction
It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction
Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time
The sixth major extinction
Terminology
Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists
Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed
Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years
Jurassic Period period when dinosaurs flourished
Something for you to do
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
4 The first mass extinction was caused byhellip
A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above
5 The most famous extinction took placehellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and airB Water and airC Land and airD Water and land
9 Iridium ishellip
A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction
Solution
1 B
2 A
3 C
4 D
5 A
6 C
7 B
8 D
9 A
10 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 1 of 15
Mass extinctions
A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major
mass extinction events in Earths history
These are shown in the table given along with the major events that characterised each
Learn about the five major mass extinctions that occurred in Earths history
Video 2CY4
Five of the following extinction events are recognised (listed from the most recent at top of the list to the
earliest oldest at bottom of list
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
bull End-Triassic
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull Late Devonian
bull Late Ordovician
Major mass extinction event
Date of occurrence
Major events
Cretaceous-Paleogene extinction event
65 million years ago
Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates
Triassic-Jurassic event
205 million years ago
Most non-dinosaur species were eliminated leaving land dinosaurs with no competition
Permian-Triassic event
250 million years ago
This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection
Late Devonian extinction
375ndash360 million years ago
This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated
Ordovician-Silurian extinction event
450ndash440 million years ago
Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 2 of 15
Causes of mass extinctions (ESGCW)
Watch a video about the debate about what really killed the dinosaurs
Video 2CY6
There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory
to explain what caused mass extinctions the theory must
bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg
dinosaurs)
bull Explain why some organisms died and others survived
bull Be based on natural events and processes that are shown to have occurred around the time of
extinction
Two of the hypotheses put forward are
bull the impact theory of extinction
bull massive volcanic activity
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 3 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 4 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 5 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 6 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Two Particular Extinctions
Scientists are not sure about the exact cause of this mass extinction
However the following are some of the conditions that occurred during this timeo there was a sharp drop in temperatureo the water of the seas evaporates
The mass extinction of 65 million years - Causes
Two Particular Extinctions
Many of the plants the source of food for the dinosaurs died out
Iridium was found in a thin layer of clay
Iridium is an element that is very rare on earth but common in meteorites
A huge crater was found in the Caribbean Sea
There were many volcanic eruptions in India
The mass extinction of 65 million years - Causes
Two Particular Extinctions
The above evidence lead to the formation of three hypothesis
The most common hypothesis is that an asteroid crashed onto Earth causing global climate change
The climate change lead to the mass extinction
The layer of iridium and the large crater in the Caribbean sea support this hypothesis
The mass extinction of 65 million years ago - Hypothesis
Two Particular Extinctions
This hypothesis deals with the continental drift theory movement of continents away from each other
It is believed that the continental drift led to the climate change
The mass extinction of 65 million years ago- Hypothesis 2
Two Particular Extinctions
This hypothesis deals with the volcanic activity in India
It is believed that this volcanic activity released particles into the air
These particles blocked out the sun for a long period of time
This resulted in the lowering of temperatures on Earth
Therefore many species died out because they could not adapt to the low temperature
The mass extinction of 65 million years ago ndash Hypothesis 3
Two Particular Extinctions
Scientists accept all three theories
Mass extinction was caused by climate change
The climate change was caused by the asteroid impact and volcanic activity
The mass extinction of 65 million years
The Holocene Epoch
The next major extinction is occurring presently
This is the sixth mass extinction
Human exploitation of the environment is the cause of this mass extinction
It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction
Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time
The sixth major extinction
Terminology
Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists
Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed
Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years
Jurassic Period period when dinosaurs flourished
Something for you to do
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
4 The first mass extinction was caused byhellip
A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above
5 The most famous extinction took placehellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and airB Water and airC Land and airD Water and land
9 Iridium ishellip
A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction
Solution
1 B
2 A
3 C
4 D
5 A
6 C
7 B
8 D
9 A
10 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 1 of 15
Mass extinctions
A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major
mass extinction events in Earths history
These are shown in the table given along with the major events that characterised each
Learn about the five major mass extinctions that occurred in Earths history
Video 2CY4
Five of the following extinction events are recognised (listed from the most recent at top of the list to the
earliest oldest at bottom of list
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
bull End-Triassic
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull Late Devonian
bull Late Ordovician
Major mass extinction event
Date of occurrence
Major events
Cretaceous-Paleogene extinction event
65 million years ago
Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates
Triassic-Jurassic event
205 million years ago
Most non-dinosaur species were eliminated leaving land dinosaurs with no competition
Permian-Triassic event
250 million years ago
This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection
Late Devonian extinction
375ndash360 million years ago
This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated
Ordovician-Silurian extinction event
450ndash440 million years ago
Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 2 of 15
Causes of mass extinctions (ESGCW)
Watch a video about the debate about what really killed the dinosaurs
Video 2CY6
There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory
to explain what caused mass extinctions the theory must
bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg
dinosaurs)
bull Explain why some organisms died and others survived
bull Be based on natural events and processes that are shown to have occurred around the time of
extinction
Two of the hypotheses put forward are
bull the impact theory of extinction
bull massive volcanic activity
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 3 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 4 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 5 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 6 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Two Particular Extinctions
Many of the plants the source of food for the dinosaurs died out
Iridium was found in a thin layer of clay
Iridium is an element that is very rare on earth but common in meteorites
A huge crater was found in the Caribbean Sea
There were many volcanic eruptions in India
The mass extinction of 65 million years - Causes
Two Particular Extinctions
The above evidence lead to the formation of three hypothesis
The most common hypothesis is that an asteroid crashed onto Earth causing global climate change
The climate change lead to the mass extinction
The layer of iridium and the large crater in the Caribbean sea support this hypothesis
The mass extinction of 65 million years ago - Hypothesis
Two Particular Extinctions
This hypothesis deals with the continental drift theory movement of continents away from each other
It is believed that the continental drift led to the climate change
The mass extinction of 65 million years ago- Hypothesis 2
Two Particular Extinctions
This hypothesis deals with the volcanic activity in India
It is believed that this volcanic activity released particles into the air
These particles blocked out the sun for a long period of time
This resulted in the lowering of temperatures on Earth
Therefore many species died out because they could not adapt to the low temperature
The mass extinction of 65 million years ago ndash Hypothesis 3
Two Particular Extinctions
Scientists accept all three theories
Mass extinction was caused by climate change
The climate change was caused by the asteroid impact and volcanic activity
The mass extinction of 65 million years
The Holocene Epoch
The next major extinction is occurring presently
This is the sixth mass extinction
Human exploitation of the environment is the cause of this mass extinction
It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction
Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time
The sixth major extinction
Terminology
Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists
Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed
Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years
Jurassic Period period when dinosaurs flourished
Something for you to do
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
4 The first mass extinction was caused byhellip
A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above
5 The most famous extinction took placehellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and airB Water and airC Land and airD Water and land
9 Iridium ishellip
A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction
Solution
1 B
2 A
3 C
4 D
5 A
6 C
7 B
8 D
9 A
10 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 1 of 15
Mass extinctions
A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major
mass extinction events in Earths history
These are shown in the table given along with the major events that characterised each
Learn about the five major mass extinctions that occurred in Earths history
Video 2CY4
Five of the following extinction events are recognised (listed from the most recent at top of the list to the
earliest oldest at bottom of list
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
bull End-Triassic
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull Late Devonian
bull Late Ordovician
Major mass extinction event
Date of occurrence
Major events
Cretaceous-Paleogene extinction event
65 million years ago
Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates
Triassic-Jurassic event
205 million years ago
Most non-dinosaur species were eliminated leaving land dinosaurs with no competition
Permian-Triassic event
250 million years ago
This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection
Late Devonian extinction
375ndash360 million years ago
This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated
Ordovician-Silurian extinction event
450ndash440 million years ago
Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 2 of 15
Causes of mass extinctions (ESGCW)
Watch a video about the debate about what really killed the dinosaurs
Video 2CY6
There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory
to explain what caused mass extinctions the theory must
bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg
dinosaurs)
bull Explain why some organisms died and others survived
bull Be based on natural events and processes that are shown to have occurred around the time of
extinction
Two of the hypotheses put forward are
bull the impact theory of extinction
bull massive volcanic activity
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 3 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 4 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 5 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 6 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 7 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Two Particular Extinctions
The above evidence lead to the formation of three hypothesis
The most common hypothesis is that an asteroid crashed onto Earth causing global climate change
The climate change lead to the mass extinction
The layer of iridium and the large crater in the Caribbean sea support this hypothesis
The mass extinction of 65 million years ago - Hypothesis
Two Particular Extinctions
This hypothesis deals with the continental drift theory movement of continents away from each other
It is believed that the continental drift led to the climate change
The mass extinction of 65 million years ago- Hypothesis 2
Two Particular Extinctions
This hypothesis deals with the volcanic activity in India
It is believed that this volcanic activity released particles into the air
These particles blocked out the sun for a long period of time
This resulted in the lowering of temperatures on Earth
Therefore many species died out because they could not adapt to the low temperature
The mass extinction of 65 million years ago ndash Hypothesis 3
Two Particular Extinctions
Scientists accept all three theories
Mass extinction was caused by climate change
The climate change was caused by the asteroid impact and volcanic activity
The mass extinction of 65 million years
The Holocene Epoch
The next major extinction is occurring presently
This is the sixth mass extinction
Human exploitation of the environment is the cause of this mass extinction
It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction
Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time
The sixth major extinction
Terminology
Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists
Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed
Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years
Jurassic Period period when dinosaurs flourished
Something for you to do
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
4 The first mass extinction was caused byhellip
A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above
5 The most famous extinction took placehellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and airB Water and airC Land and airD Water and land
9 Iridium ishellip
A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction
Solution
1 B
2 A
3 C
4 D
5 A
6 C
7 B
8 D
9 A
10 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 1 of 15
Mass extinctions
A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major
mass extinction events in Earths history
These are shown in the table given along with the major events that characterised each
Learn about the five major mass extinctions that occurred in Earths history
Video 2CY4
Five of the following extinction events are recognised (listed from the most recent at top of the list to the
earliest oldest at bottom of list
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
bull End-Triassic
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull Late Devonian
bull Late Ordovician
Major mass extinction event
Date of occurrence
Major events
Cretaceous-Paleogene extinction event
65 million years ago
Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates
Triassic-Jurassic event
205 million years ago
Most non-dinosaur species were eliminated leaving land dinosaurs with no competition
Permian-Triassic event
250 million years ago
This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection
Late Devonian extinction
375ndash360 million years ago
This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated
Ordovician-Silurian extinction event
450ndash440 million years ago
Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 2 of 15
Causes of mass extinctions (ESGCW)
Watch a video about the debate about what really killed the dinosaurs
Video 2CY6
There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory
to explain what caused mass extinctions the theory must
bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg
dinosaurs)
bull Explain why some organisms died and others survived
bull Be based on natural events and processes that are shown to have occurred around the time of
extinction
Two of the hypotheses put forward are
bull the impact theory of extinction
bull massive volcanic activity
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 3 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 4 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 5 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 6 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Two Particular Extinctions
This hypothesis deals with the continental drift theory movement of continents away from each other
It is believed that the continental drift led to the climate change
The mass extinction of 65 million years ago- Hypothesis 2
Two Particular Extinctions
This hypothesis deals with the volcanic activity in India
It is believed that this volcanic activity released particles into the air
These particles blocked out the sun for a long period of time
This resulted in the lowering of temperatures on Earth
Therefore many species died out because they could not adapt to the low temperature
The mass extinction of 65 million years ago ndash Hypothesis 3
Two Particular Extinctions
Scientists accept all three theories
Mass extinction was caused by climate change
The climate change was caused by the asteroid impact and volcanic activity
The mass extinction of 65 million years
The Holocene Epoch
The next major extinction is occurring presently
This is the sixth mass extinction
Human exploitation of the environment is the cause of this mass extinction
It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction
Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time
The sixth major extinction
Terminology
Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists
Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed
Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years
Jurassic Period period when dinosaurs flourished
Something for you to do
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
4 The first mass extinction was caused byhellip
A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above
5 The most famous extinction took placehellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and airB Water and airC Land and airD Water and land
9 Iridium ishellip
A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction
Solution
1 B
2 A
3 C
4 D
5 A
6 C
7 B
8 D
9 A
10 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 1 of 15
Mass extinctions
A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major
mass extinction events in Earths history
These are shown in the table given along with the major events that characterised each
Learn about the five major mass extinctions that occurred in Earths history
Video 2CY4
Five of the following extinction events are recognised (listed from the most recent at top of the list to the
earliest oldest at bottom of list
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
bull End-Triassic
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull Late Devonian
bull Late Ordovician
Major mass extinction event
Date of occurrence
Major events
Cretaceous-Paleogene extinction event
65 million years ago
Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates
Triassic-Jurassic event
205 million years ago
Most non-dinosaur species were eliminated leaving land dinosaurs with no competition
Permian-Triassic event
250 million years ago
This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection
Late Devonian extinction
375ndash360 million years ago
This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated
Ordovician-Silurian extinction event
450ndash440 million years ago
Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 2 of 15
Causes of mass extinctions (ESGCW)
Watch a video about the debate about what really killed the dinosaurs
Video 2CY6
There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory
to explain what caused mass extinctions the theory must
bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg
dinosaurs)
bull Explain why some organisms died and others survived
bull Be based on natural events and processes that are shown to have occurred around the time of
extinction
Two of the hypotheses put forward are
bull the impact theory of extinction
bull massive volcanic activity
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Two Particular Extinctions
This hypothesis deals with the volcanic activity in India
It is believed that this volcanic activity released particles into the air
These particles blocked out the sun for a long period of time
This resulted in the lowering of temperatures on Earth
Therefore many species died out because they could not adapt to the low temperature
The mass extinction of 65 million years ago ndash Hypothesis 3
Two Particular Extinctions
Scientists accept all three theories
Mass extinction was caused by climate change
The climate change was caused by the asteroid impact and volcanic activity
The mass extinction of 65 million years
The Holocene Epoch
The next major extinction is occurring presently
This is the sixth mass extinction
Human exploitation of the environment is the cause of this mass extinction
It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction
Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time
The sixth major extinction
Terminology
Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists
Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed
Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years
Jurassic Period period when dinosaurs flourished
Something for you to do
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
4 The first mass extinction was caused byhellip
A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above
5 The most famous extinction took placehellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and airB Water and airC Land and airD Water and land
9 Iridium ishellip
A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction
Solution
1 B
2 A
3 C
4 D
5 A
6 C
7 B
8 D
9 A
10 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 1 of 15
Mass extinctions
A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major
mass extinction events in Earths history
These are shown in the table given along with the major events that characterised each
Learn about the five major mass extinctions that occurred in Earths history
Video 2CY4
Five of the following extinction events are recognised (listed from the most recent at top of the list to the
earliest oldest at bottom of list
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
bull End-Triassic
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull Late Devonian
bull Late Ordovician
Major mass extinction event
Date of occurrence
Major events
Cretaceous-Paleogene extinction event
65 million years ago
Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates
Triassic-Jurassic event
205 million years ago
Most non-dinosaur species were eliminated leaving land dinosaurs with no competition
Permian-Triassic event
250 million years ago
This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection
Late Devonian extinction
375ndash360 million years ago
This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated
Ordovician-Silurian extinction event
450ndash440 million years ago
Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 2 of 15
Causes of mass extinctions (ESGCW)
Watch a video about the debate about what really killed the dinosaurs
Video 2CY6
There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory
to explain what caused mass extinctions the theory must
bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg
dinosaurs)
bull Explain why some organisms died and others survived
bull Be based on natural events and processes that are shown to have occurred around the time of
extinction
Two of the hypotheses put forward are
bull the impact theory of extinction
bull massive volcanic activity
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 3 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 4 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 5 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 6 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Two Particular Extinctions
Scientists accept all three theories
Mass extinction was caused by climate change
The climate change was caused by the asteroid impact and volcanic activity
The mass extinction of 65 million years
The Holocene Epoch
The next major extinction is occurring presently
This is the sixth mass extinction
Human exploitation of the environment is the cause of this mass extinction
It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction
Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time
The sixth major extinction
Terminology
Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists
Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed
Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years
Jurassic Period period when dinosaurs flourished
Something for you to do
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
4 The first mass extinction was caused byhellip
A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above
5 The most famous extinction took placehellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and airB Water and airC Land and airD Water and land
9 Iridium ishellip
A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction
Solution
1 B
2 A
3 C
4 D
5 A
6 C
7 B
8 D
9 A
10 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 1 of 15
Mass extinctions
A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major
mass extinction events in Earths history
These are shown in the table given along with the major events that characterised each
Learn about the five major mass extinctions that occurred in Earths history
Video 2CY4
Five of the following extinction events are recognised (listed from the most recent at top of the list to the
earliest oldest at bottom of list
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
bull End-Triassic
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull Late Devonian
bull Late Ordovician
Major mass extinction event
Date of occurrence
Major events
Cretaceous-Paleogene extinction event
65 million years ago
Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates
Triassic-Jurassic event
205 million years ago
Most non-dinosaur species were eliminated leaving land dinosaurs with no competition
Permian-Triassic event
250 million years ago
This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection
Late Devonian extinction
375ndash360 million years ago
This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated
Ordovician-Silurian extinction event
450ndash440 million years ago
Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 2 of 15
Causes of mass extinctions (ESGCW)
Watch a video about the debate about what really killed the dinosaurs
Video 2CY6
There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory
to explain what caused mass extinctions the theory must
bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg
dinosaurs)
bull Explain why some organisms died and others survived
bull Be based on natural events and processes that are shown to have occurred around the time of
extinction
Two of the hypotheses put forward are
bull the impact theory of extinction
bull massive volcanic activity
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 3 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 4 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 5 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
The Holocene Epoch
The next major extinction is occurring presently
This is the sixth mass extinction
Human exploitation of the environment is the cause of this mass extinction
It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction
Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time
The sixth major extinction
Terminology
Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists
Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed
Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years
Jurassic Period period when dinosaurs flourished
Something for you to do
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
4 The first mass extinction was caused byhellip
A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above
5 The most famous extinction took placehellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and airB Water and airC Land and airD Water and land
9 Iridium ishellip
A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction
Solution
1 B
2 A
3 C
4 D
5 A
6 C
7 B
8 D
9 A
10 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 1 of 15
Mass extinctions
A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major
mass extinction events in Earths history
These are shown in the table given along with the major events that characterised each
Learn about the five major mass extinctions that occurred in Earths history
Video 2CY4
Five of the following extinction events are recognised (listed from the most recent at top of the list to the
earliest oldest at bottom of list
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
bull End-Triassic
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull Late Devonian
bull Late Ordovician
Major mass extinction event
Date of occurrence
Major events
Cretaceous-Paleogene extinction event
65 million years ago
Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates
Triassic-Jurassic event
205 million years ago
Most non-dinosaur species were eliminated leaving land dinosaurs with no competition
Permian-Triassic event
250 million years ago
This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection
Late Devonian extinction
375ndash360 million years ago
This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated
Ordovician-Silurian extinction event
450ndash440 million years ago
Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 2 of 15
Causes of mass extinctions (ESGCW)
Watch a video about the debate about what really killed the dinosaurs
Video 2CY6
There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory
to explain what caused mass extinctions the theory must
bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg
dinosaurs)
bull Explain why some organisms died and others survived
bull Be based on natural events and processes that are shown to have occurred around the time of
extinction
Two of the hypotheses put forward are
bull the impact theory of extinction
bull massive volcanic activity
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 3 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 4 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 5 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 6 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 7 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Terminology
Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists
Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed
Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years
Jurassic Period period when dinosaurs flourished
Something for you to do
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
4 The first mass extinction was caused byhellip
A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above
5 The most famous extinction took placehellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and airB Water and airC Land and airD Water and land
9 Iridium ishellip
A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction
Solution
1 B
2 A
3 C
4 D
5 A
6 C
7 B
8 D
9 A
10 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 1 of 15
Mass extinctions
A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major
mass extinction events in Earths history
These are shown in the table given along with the major events that characterised each
Learn about the five major mass extinctions that occurred in Earths history
Video 2CY4
Five of the following extinction events are recognised (listed from the most recent at top of the list to the
earliest oldest at bottom of list
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
bull End-Triassic
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull Late Devonian
bull Late Ordovician
Major mass extinction event
Date of occurrence
Major events
Cretaceous-Paleogene extinction event
65 million years ago
Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates
Triassic-Jurassic event
205 million years ago
Most non-dinosaur species were eliminated leaving land dinosaurs with no competition
Permian-Triassic event
250 million years ago
This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection
Late Devonian extinction
375ndash360 million years ago
This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated
Ordovician-Silurian extinction event
450ndash440 million years ago
Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 2 of 15
Causes of mass extinctions (ESGCW)
Watch a video about the debate about what really killed the dinosaurs
Video 2CY6
There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory
to explain what caused mass extinctions the theory must
bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg
dinosaurs)
bull Explain why some organisms died and others survived
bull Be based on natural events and processes that are shown to have occurred around the time of
extinction
Two of the hypotheses put forward are
bull the impact theory of extinction
bull massive volcanic activity
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 3 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 4 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 5 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Something for you to do
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
4 The first mass extinction was caused byhellip
A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above
5 The most famous extinction took placehellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and airB Water and airC Land and airD Water and land
9 Iridium ishellip
A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction
Solution
1 B
2 A
3 C
4 D
5 A
6 C
7 B
8 D
9 A
10 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 1 of 15
Mass extinctions
A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major
mass extinction events in Earths history
These are shown in the table given along with the major events that characterised each
Learn about the five major mass extinctions that occurred in Earths history
Video 2CY4
Five of the following extinction events are recognised (listed from the most recent at top of the list to the
earliest oldest at bottom of list
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
bull End-Triassic
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull Late Devonian
bull Late Ordovician
Major mass extinction event
Date of occurrence
Major events
Cretaceous-Paleogene extinction event
65 million years ago
Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates
Triassic-Jurassic event
205 million years ago
Most non-dinosaur species were eliminated leaving land dinosaurs with no competition
Permian-Triassic event
250 million years ago
This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection
Late Devonian extinction
375ndash360 million years ago
This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated
Ordovician-Silurian extinction event
450ndash440 million years ago
Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 2 of 15
Causes of mass extinctions (ESGCW)
Watch a video about the debate about what really killed the dinosaurs
Video 2CY6
There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory
to explain what caused mass extinctions the theory must
bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg
dinosaurs)
bull Explain why some organisms died and others survived
bull Be based on natural events and processes that are shown to have occurred around the time of
extinction
Two of the hypotheses put forward are
bull the impact theory of extinction
bull massive volcanic activity
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 3 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 4 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 5 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 6 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
4 The first mass extinction was caused byhellip
A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above
5 The most famous extinction took placehellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and airB Water and airC Land and airD Water and land
9 Iridium ishellip
A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction
Solution
1 B
2 A
3 C
4 D
5 A
6 C
7 B
8 D
9 A
10 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 1 of 15
Mass extinctions
A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major
mass extinction events in Earths history
These are shown in the table given along with the major events that characterised each
Learn about the five major mass extinctions that occurred in Earths history
Video 2CY4
Five of the following extinction events are recognised (listed from the most recent at top of the list to the
earliest oldest at bottom of list
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
bull End-Triassic
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull Late Devonian
bull Late Ordovician
Major mass extinction event
Date of occurrence
Major events
Cretaceous-Paleogene extinction event
65 million years ago
Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates
Triassic-Jurassic event
205 million years ago
Most non-dinosaur species were eliminated leaving land dinosaurs with no competition
Permian-Triassic event
250 million years ago
This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection
Late Devonian extinction
375ndash360 million years ago
This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated
Ordovician-Silurian extinction event
450ndash440 million years ago
Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 2 of 15
Causes of mass extinctions (ESGCW)
Watch a video about the debate about what really killed the dinosaurs
Video 2CY6
There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory
to explain what caused mass extinctions the theory must
bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg
dinosaurs)
bull Explain why some organisms died and others survived
bull Be based on natural events and processes that are shown to have occurred around the time of
extinction
Two of the hypotheses put forward are
bull the impact theory of extinction
bull massive volcanic activity
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 3 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 4 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 5 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 6 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 7 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
3 The name given to the extinction characterized by the death of large mammals
A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above
4 The first mass extinction was caused byhellip
A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above
5 The most famous extinction took placehellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and airB Water and airC Land and airD Water and land
9 Iridium ishellip
A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction
Solution
1 B
2 A
3 C
4 D
5 A
6 C
7 B
8 D
9 A
10 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 1 of 15
Mass extinctions
A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major
mass extinction events in Earths history
These are shown in the table given along with the major events that characterised each
Learn about the five major mass extinctions that occurred in Earths history
Video 2CY4
Five of the following extinction events are recognised (listed from the most recent at top of the list to the
earliest oldest at bottom of list
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
bull End-Triassic
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull Late Devonian
bull Late Ordovician
Major mass extinction event
Date of occurrence
Major events
Cretaceous-Paleogene extinction event
65 million years ago
Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates
Triassic-Jurassic event
205 million years ago
Most non-dinosaur species were eliminated leaving land dinosaurs with no competition
Permian-Triassic event
250 million years ago
This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection
Late Devonian extinction
375ndash360 million years ago
This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated
Ordovician-Silurian extinction event
450ndash440 million years ago
Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 2 of 15
Causes of mass extinctions (ESGCW)
Watch a video about the debate about what really killed the dinosaurs
Video 2CY6
There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory
to explain what caused mass extinctions the theory must
bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg
dinosaurs)
bull Explain why some organisms died and others survived
bull Be based on natural events and processes that are shown to have occurred around the time of
extinction
Two of the hypotheses put forward are
bull the impact theory of extinction
bull massive volcanic activity
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 3 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 4 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 5 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 6 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 7 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
4 The first mass extinction was caused byhellip
A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above
5 The most famous extinction took placehellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and airB Water and airC Land and airD Water and land
9 Iridium ishellip
A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction
Solution
1 B
2 A
3 C
4 D
5 A
6 C
7 B
8 D
9 A
10 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 1 of 15
Mass extinctions
A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major
mass extinction events in Earths history
These are shown in the table given along with the major events that characterised each
Learn about the five major mass extinctions that occurred in Earths history
Video 2CY4
Five of the following extinction events are recognised (listed from the most recent at top of the list to the
earliest oldest at bottom of list
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
bull End-Triassic
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull Late Devonian
bull Late Ordovician
Major mass extinction event
Date of occurrence
Major events
Cretaceous-Paleogene extinction event
65 million years ago
Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates
Triassic-Jurassic event
205 million years ago
Most non-dinosaur species were eliminated leaving land dinosaurs with no competition
Permian-Triassic event
250 million years ago
This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection
Late Devonian extinction
375ndash360 million years ago
This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated
Ordovician-Silurian extinction event
450ndash440 million years ago
Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 2 of 15
Causes of mass extinctions (ESGCW)
Watch a video about the debate about what really killed the dinosaurs
Video 2CY6
There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory
to explain what caused mass extinctions the theory must
bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg
dinosaurs)
bull Explain why some organisms died and others survived
bull Be based on natural events and processes that are shown to have occurred around the time of
extinction
Two of the hypotheses put forward are
bull the impact theory of extinction
bull massive volcanic activity
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 3 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 4 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 5 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 6 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 7 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
5 The most famous extinction took placehellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and airB Water and airC Land and airD Water and land
9 Iridium ishellip
A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction
Solution
1 B
2 A
3 C
4 D
5 A
6 C
7 B
8 D
9 A
10 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 1 of 15
Mass extinctions
A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major
mass extinction events in Earths history
These are shown in the table given along with the major events that characterised each
Learn about the five major mass extinctions that occurred in Earths history
Video 2CY4
Five of the following extinction events are recognised (listed from the most recent at top of the list to the
earliest oldest at bottom of list
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
bull End-Triassic
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull Late Devonian
bull Late Ordovician
Major mass extinction event
Date of occurrence
Major events
Cretaceous-Paleogene extinction event
65 million years ago
Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates
Triassic-Jurassic event
205 million years ago
Most non-dinosaur species were eliminated leaving land dinosaurs with no competition
Permian-Triassic event
250 million years ago
This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection
Late Devonian extinction
375ndash360 million years ago
This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated
Ordovician-Silurian extinction event
450ndash440 million years ago
Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 2 of 15
Causes of mass extinctions (ESGCW)
Watch a video about the debate about what really killed the dinosaurs
Video 2CY6
There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory
to explain what caused mass extinctions the theory must
bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg
dinosaurs)
bull Explain why some organisms died and others survived
bull Be based on natural events and processes that are shown to have occurred around the time of
extinction
Two of the hypotheses put forward are
bull the impact theory of extinction
bull massive volcanic activity
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 3 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 4 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 5 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 6 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 7 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and airB Water and airC Land and airD Water and land
9 Iridium ishellip
A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction
Solution
1 B
2 A
3 C
4 D
5 A
6 C
7 B
8 D
9 A
10 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 1 of 15
Mass extinctions
A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major
mass extinction events in Earths history
These are shown in the table given along with the major events that characterised each
Learn about the five major mass extinctions that occurred in Earths history
Video 2CY4
Five of the following extinction events are recognised (listed from the most recent at top of the list to the
earliest oldest at bottom of list
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
bull End-Triassic
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull Late Devonian
bull Late Ordovician
Major mass extinction event
Date of occurrence
Major events
Cretaceous-Paleogene extinction event
65 million years ago
Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates
Triassic-Jurassic event
205 million years ago
Most non-dinosaur species were eliminated leaving land dinosaurs with no competition
Permian-Triassic event
250 million years ago
This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection
Late Devonian extinction
375ndash360 million years ago
This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated
Ordovician-Silurian extinction event
450ndash440 million years ago
Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 2 of 15
Causes of mass extinctions (ESGCW)
Watch a video about the debate about what really killed the dinosaurs
Video 2CY6
There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory
to explain what caused mass extinctions the theory must
bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg
dinosaurs)
bull Explain why some organisms died and others survived
bull Be based on natural events and processes that are shown to have occurred around the time of
extinction
Two of the hypotheses put forward are
bull the impact theory of extinction
bull massive volcanic activity
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 3 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 4 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 5 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 6 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 7 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
7 The most serious mass extinction took places more thanhellip
A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and airB Water and airC Land and airD Water and land
9 Iridium ishellip
A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction
Solution
1 B
2 A
3 C
4 D
5 A
6 C
7 B
8 D
9 A
10 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 1 of 15
Mass extinctions
A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major
mass extinction events in Earths history
These are shown in the table given along with the major events that characterised each
Learn about the five major mass extinctions that occurred in Earths history
Video 2CY4
Five of the following extinction events are recognised (listed from the most recent at top of the list to the
earliest oldest at bottom of list
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
bull End-Triassic
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull Late Devonian
bull Late Ordovician
Major mass extinction event
Date of occurrence
Major events
Cretaceous-Paleogene extinction event
65 million years ago
Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates
Triassic-Jurassic event
205 million years ago
Most non-dinosaur species were eliminated leaving land dinosaurs with no competition
Permian-Triassic event
250 million years ago
This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection
Late Devonian extinction
375ndash360 million years ago
This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated
Ordovician-Silurian extinction event
450ndash440 million years ago
Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 2 of 15
Causes of mass extinctions (ESGCW)
Watch a video about the debate about what really killed the dinosaurs
Video 2CY6
There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory
to explain what caused mass extinctions the theory must
bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg
dinosaurs)
bull Explain why some organisms died and others survived
bull Be based on natural events and processes that are shown to have occurred around the time of
extinction
Two of the hypotheses put forward are
bull the impact theory of extinction
bull massive volcanic activity
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 3 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 4 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 5 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
8 Dinosaurs dominated thehellip
A Water land and airB Water and airC Land and airD Water and land
9 Iridium ishellip
A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction
Solution
1 B
2 A
3 C
4 D
5 A
6 C
7 B
8 D
9 A
10 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 1 of 15
Mass extinctions
A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major
mass extinction events in Earths history
These are shown in the table given along with the major events that characterised each
Learn about the five major mass extinctions that occurred in Earths history
Video 2CY4
Five of the following extinction events are recognised (listed from the most recent at top of the list to the
earliest oldest at bottom of list
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
bull End-Triassic
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull Late Devonian
bull Late Ordovician
Major mass extinction event
Date of occurrence
Major events
Cretaceous-Paleogene extinction event
65 million years ago
Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates
Triassic-Jurassic event
205 million years ago
Most non-dinosaur species were eliminated leaving land dinosaurs with no competition
Permian-Triassic event
250 million years ago
This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection
Late Devonian extinction
375ndash360 million years ago
This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated
Ordovician-Silurian extinction event
450ndash440 million years ago
Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 2 of 15
Causes of mass extinctions (ESGCW)
Watch a video about the debate about what really killed the dinosaurs
Video 2CY6
There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory
to explain what caused mass extinctions the theory must
bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg
dinosaurs)
bull Explain why some organisms died and others survived
bull Be based on natural events and processes that are shown to have occurred around the time of
extinction
Two of the hypotheses put forward are
bull the impact theory of extinction
bull massive volcanic activity
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 3 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 4 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 5 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 6 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 7 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
9 Iridium ishellip
A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction
Solution
1 B
2 A
3 C
4 D
5 A
6 C
7 B
8 D
9 A
10 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 1 of 15
Mass extinctions
A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major
mass extinction events in Earths history
These are shown in the table given along with the major events that characterised each
Learn about the five major mass extinctions that occurred in Earths history
Video 2CY4
Five of the following extinction events are recognised (listed from the most recent at top of the list to the
earliest oldest at bottom of list
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
bull End-Triassic
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull Late Devonian
bull Late Ordovician
Major mass extinction event
Date of occurrence
Major events
Cretaceous-Paleogene extinction event
65 million years ago
Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates
Triassic-Jurassic event
205 million years ago
Most non-dinosaur species were eliminated leaving land dinosaurs with no competition
Permian-Triassic event
250 million years ago
This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection
Late Devonian extinction
375ndash360 million years ago
This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated
Ordovician-Silurian extinction event
450ndash440 million years ago
Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 2 of 15
Causes of mass extinctions (ESGCW)
Watch a video about the debate about what really killed the dinosaurs
Video 2CY6
There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory
to explain what caused mass extinctions the theory must
bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg
dinosaurs)
bull Explain why some organisms died and others survived
bull Be based on natural events and processes that are shown to have occurred around the time of
extinction
Two of the hypotheses put forward are
bull the impact theory of extinction
bull massive volcanic activity
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 3 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 4 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 5 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 6 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 7 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction
Solution
1 B
2 A
3 C
4 D
5 A
6 C
7 B
8 D
9 A
10 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 1 of 15
Mass extinctions
A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major
mass extinction events in Earths history
These are shown in the table given along with the major events that characterised each
Learn about the five major mass extinctions that occurred in Earths history
Video 2CY4
Five of the following extinction events are recognised (listed from the most recent at top of the list to the
earliest oldest at bottom of list
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
bull End-Triassic
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull Late Devonian
bull Late Ordovician
Major mass extinction event
Date of occurrence
Major events
Cretaceous-Paleogene extinction event
65 million years ago
Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates
Triassic-Jurassic event
205 million years ago
Most non-dinosaur species were eliminated leaving land dinosaurs with no competition
Permian-Triassic event
250 million years ago
This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection
Late Devonian extinction
375ndash360 million years ago
This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated
Ordovician-Silurian extinction event
450ndash440 million years ago
Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 2 of 15
Causes of mass extinctions (ESGCW)
Watch a video about the debate about what really killed the dinosaurs
Video 2CY6
There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory
to explain what caused mass extinctions the theory must
bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg
dinosaurs)
bull Explain why some organisms died and others survived
bull Be based on natural events and processes that are shown to have occurred around the time of
extinction
Two of the hypotheses put forward are
bull the impact theory of extinction
bull massive volcanic activity
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 3 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 4 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 5 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 6 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 7 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Solution
1 B
2 A
3 C
4 D
5 A
6 C
7 B
8 D
9 A
10 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 1 of 15
Mass extinctions
A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major
mass extinction events in Earths history
These are shown in the table given along with the major events that characterised each
Learn about the five major mass extinctions that occurred in Earths history
Video 2CY4
Five of the following extinction events are recognised (listed from the most recent at top of the list to the
earliest oldest at bottom of list
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
bull End-Triassic
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull Late Devonian
bull Late Ordovician
Major mass extinction event
Date of occurrence
Major events
Cretaceous-Paleogene extinction event
65 million years ago
Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates
Triassic-Jurassic event
205 million years ago
Most non-dinosaur species were eliminated leaving land dinosaurs with no competition
Permian-Triassic event
250 million years ago
This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection
Late Devonian extinction
375ndash360 million years ago
This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated
Ordovician-Silurian extinction event
450ndash440 million years ago
Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 2 of 15
Causes of mass extinctions (ESGCW)
Watch a video about the debate about what really killed the dinosaurs
Video 2CY6
There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory
to explain what caused mass extinctions the theory must
bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg
dinosaurs)
bull Explain why some organisms died and others survived
bull Be based on natural events and processes that are shown to have occurred around the time of
extinction
Two of the hypotheses put forward are
bull the impact theory of extinction
bull massive volcanic activity
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 3 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 4 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 5 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 6 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 1 of 15
Mass extinctions
A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major
mass extinction events in Earths history
These are shown in the table given along with the major events that characterised each
Learn about the five major mass extinctions that occurred in Earths history
Video 2CY4
Five of the following extinction events are recognised (listed from the most recent at top of the list to the
earliest oldest at bottom of list
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
bull End-Triassic
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull Late Devonian
bull Late Ordovician
Major mass extinction event
Date of occurrence
Major events
Cretaceous-Paleogene extinction event
65 million years ago
Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates
Triassic-Jurassic event
205 million years ago
Most non-dinosaur species were eliminated leaving land dinosaurs with no competition
Permian-Triassic event
250 million years ago
This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection
Late Devonian extinction
375ndash360 million years ago
This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated
Ordovician-Silurian extinction event
450ndash440 million years ago
Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 2 of 15
Causes of mass extinctions (ESGCW)
Watch a video about the debate about what really killed the dinosaurs
Video 2CY6
There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory
to explain what caused mass extinctions the theory must
bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg
dinosaurs)
bull Explain why some organisms died and others survived
bull Be based on natural events and processes that are shown to have occurred around the time of
extinction
Two of the hypotheses put forward are
bull the impact theory of extinction
bull massive volcanic activity
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 3 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 4 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 5 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 2 of 15
Causes of mass extinctions (ESGCW)
Watch a video about the debate about what really killed the dinosaurs
Video 2CY6
There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory
to explain what caused mass extinctions the theory must
bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg
dinosaurs)
bull Explain why some organisms died and others survived
bull Be based on natural events and processes that are shown to have occurred around the time of
extinction
Two of the hypotheses put forward are
bull the impact theory of extinction
bull massive volcanic activity
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 3 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
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Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 3 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 4 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 5 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 6 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 7 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 4 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 5 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 6 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 7 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 5 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 6 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 7 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 6 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 7 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 7 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 8 of 15
Other resources
httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-
travel-time-planet-600-million-years-historyhtml
httpswwwamnhorglearn-teachcurriculum-collections
httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-
earth10-history-of-life-on-earth-04
httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction
httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml
httpswwwyoutubecomwatchv=bU1QPtOZQZU
httpyoutubecomwatchv=FlUes_NPa6M
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 9 of 15
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 10 of 15
Activity 1
The diagram below represents a simplified geological time-scale showing how the number of families
(groups of related species) has changed over a period of time
11 How many mass extinctions took place since the creation of the earth (1)
12 Which mass extinction took place towards the end of the Palaeozoic era (1)
13 Which era had the longest duration (1)
14 Name TWO factors or events known to have caused mass extinctions (2)
15 When did the Triassic extinction take place (1)
16 Which extinction was the biggest in terms of the number of families that went extinct (1)
17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be
the cause of this mass extinction (1)
18 What evidence do scientists put forth today to support the idea that we are entering the sixth
extinction (2)
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 11 of 15
19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event
on par with those last seen millions of years ago Explain (5)
Activity 2
1 The process by which living organism die off so that not a single member of the species exists
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million
years
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
3 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
4 The name given to the extinction characterized by the death of large mammals
A Mass extinction
B Extinction
C Megafauna extinction
D None of the above
5 The most famous extinction took placehellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 12 of 15
6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
7 The most serious mass extinction took places more thanhellip
A 65 million years ago
B 250 million years ago
C 364 million years ago
D 439 million years ago
8 Dinosaurs dominated thehellip
A Water land and air
B Water and air
C Land and air
D Water and land
9 Iridium ishellip
A A rare element found in asteroids
B Found in the dinosaurs
C A type of dinosaur
D The sixth mass extinction
10 The highest rate of mass extinction occurs during thehellip
A sixth mass extinction
B first mass extinction
C second mass extinction
D fifth mass extinction
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 13 of 15
Activity 3
Write paragraph type of answers on each of the following extinction events
bull Late Ordovician
bull Late Devonian
bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)
bull End-Triassic
bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)
Guiding questions for research
1 When did this extinction take place
2 Describe the extent of the extinction
21 How many kinds of organisms lived on Earth before the extinction
22 What percentages were lost during the extinction
23 Did new kinds of organisms evolve after this extinction
3 What did Earth look like at that time
4 Were the continents in the same locations they are in today If not how were they arranged
5 How do scientists know what they know about the event
6 What evidence have they used to support their ideas
7 Name some of the kinds of organisms that went extinct during the extinction
8 What explanations have scientists put forth to explain why so many groups of organisms disappeared
during this extinction
9 Do scientists agree on the cause for this extinction
Name of extinction event
Criteria Description
1 Date
2 Reason for the
mass extinction
3 Number of
genera and
percentage
before the
extinction
events
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 14 of 15
4 Number of
genera and
percentage
after the
extinction event
5 New genera
that evolved
after this
extinction
6 Name some
kinds of
organisms that
went extinct
during this
extinction
7 What evidence
is there to
support the
explanation of
how the
extinction
happened
8 What did earth
look like when
this extinction
took place
(what
continents were
there at the
time)
9 Diagrams of
organisms that
went extinct
during this
extinction
event
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3
Page 15 of 15
Recap lesson What commonalities do you see among these extinctions What differences do you
see among these extinctions
Additional requirements (not compulsory)
bull The years the extinction event took place
bull A drawing or other visual representation of three species that went extinct during their event
bull A map showing the location and names of the continents at that time
bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time
bull Two facts about this extinction event that make it significant in the history of life on Earth (significant
life forms that went extinct new life forms that evolved
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
History of Life on Earth Fossils
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Agenda or Summary LayoutA summary of the presentation
1
2
3
4
Discussion Item OneWhat are fossils
Discussion Item TwoFormation of Fossils
Discussion Item ThreeDetermining the age of the fossils
Discussion Item FourEvidence for the key events in the history of life
5
6
Discussion Item FiveHuman Impact on Biodiversity and Natural Environment
Discussion Item SixFossil tourism
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
What are Fossils
Fossils are remains of ancient life forms preserved in rock
They may also occur in ice tar and dried sap of trees
The study of fossils is called paleontology
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Formation of Fossils
The richest sources of fossils are found in sedimentary rock
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom
The mineral salts also settle to the bottom
The mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Formation of Fossils
An imprint is left behind when the organism starts to decay before it becomes petrified
Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone
Imprints
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Formation of Fossils
The sedimentary rock pile up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
Sedimentary Rock
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Formation of Fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
This means that they are found in a large number of places
Index fossils
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Formation of Fossils
Some examples of fossils arehellip
bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of
animals petrified tree trunks imprints of leaves and small animals
Examples of Fossils
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Formation of Fossils
Remember fossils also occur in tar and ice
Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber
Amber is the hardened form of liquid sap of plants
Examples of Fossils
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Determining the Age of Fossils
There are two methods used to determine the age of fossils
These are relative dating and radiometric dating
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Determining the Age of Fossils
In relative dating the age of the fossil is worked by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossilAn example of geological event is an volcanic eruption
Relative dating
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Determining the Age of Fossils
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
Relative dating
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Determining the Age of Fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
Relative dating
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Determining the Age of Fossils
Radiometric dating tries to find out how long ago a particular fossil was
formed
Radiometric dating means radio comes from the word radioactive
Radioactive is used to describe substances that give off nuclear radiation
Nuclear radiation is very useful because radioactive substances decay at a
fixed rate
This means that they lose their radioactivity at a fixed rate
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radiometric Dating
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Determining the Age of Fossils
1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes
nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil
by comparing the ratio of carbon -14 to total carbon and nitrogen-14
Radiometric dating ndash the process
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Determining the Age of Fossils
Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred
Relative dating can be used to compare the fossils with the dateof the eruption
If the fossil is found in the layer above the volcanic ash then it was formed after the eruption
If it is formed in the layer below the ash then it formed before the eruption
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Key Events in Southern Africa
One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga
These are fossilized photosynthetic bacteria cells
These fossil are about 3400 million years old
The bacteria had jelly like substance around it
Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light
This results in the formation of a structure called stromatolites
Fossil Evidence
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Key Events in Southern Africa
These are dome-shaped mat like layers of rock
Stromatolites
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Key Events in Southern Africa
The oldest known multi cellular organism is found in Namibia
The multi-cellular organisms are sponges called Otavia
They are found in limestone rocks found in northern Namibia
These fossilized sponges are thought to be 650 million years old
A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape
Oldest fossil of multi-cellular organism
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Key Events in Southern Africa
Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown
These fossils are about 350 million years old
A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal
A picture of Glossopterisfossil
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa
The picture is a reconstruction of what the Glossopteris may have looked like
Key Events in Southern AfricaGlossopteris
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Map showing Coal Deposits in South Africa
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo
Key Events in Southern AfricaReptiles
These reptiles were believed to give rise to mammals
They lived between 280 and 100 million years ago
Lystrosaurus
Thrinaxodon
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Key Events in Southern Africa
Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape
This is supported by findings of fossilized footprints of dinosaurs in these areas
Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges
Dinosaurs
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Euskelosarus was a very early dinosaur
It was a herbivore
The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State
Euskelosarus
Key Events in Southern AfricaDinosaurs
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Key Events in Southern Africa
There is evidence of early mammals in Southern Africa
This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho
The caves of the Cradle of Humankind contains most of the fossil evidence of early humans
Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape
This evidence is in the form of fossils and artefacts
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
The diagram shows a example of a Coelacanths
Some of their fins are lobe like
This and many other features have led scientists to believe that they are more closely related to amphibians than fish
Coelacanths were thought to have become extinct about 70 million years ago
However in 1938 a living coelacanth was caught of the coast of East London
A population of about 15 coelacanths have been found near Sodwana Bay
Coelacanths are also called the living fossil
Key Events in Southern AfricaCoelacanths
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Human Impact on Biodiversity and the Natural
Environment
Some of the treats are listed below
1 Habitat destruction
2 Natural disasters
3 Over-exploitation
4 Pollution
5 Pesticides and fertilizers
6 Climate change
7 Alien invasive species
8 Disease
Threats to Biodiversity and the Natural Environment
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Fossil tourism
Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils
One of the most famous fossils sites is the Cradle of Humankind
The Cradle of Humankind is found in Gauteng and North West Province
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Fossil tourism
Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999
It is one of the richest source of fossils of early humans
Nearly half of all human-ancestor fossils have been found here
Cradle of Humankind
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Fossil tourism
The West Coast Fossil Park is found in the Western Cape Province
It is found along the west coast a few kilometers inland of the Langebaan Lagoon
This was once a phosphate mine
It has the greatest diversity of five million old fossils
It contained the fossils of the first bear ever found south of the Sahara
Fossils of the extinct true seal and four extinct species of penguins were found here
West Coast Fossil Park
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Fossil tourism
The many hand on activities at the park that makes it very exciting for the tourist
Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you
Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle
West Coast Fossil Park
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Fossil tourism
Important fossils have been moved to museums once they have been discovered
The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet
The museums become important fossil tourist attractions
Museums
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Fossil tourism
Fossil tourism
1 Creates jobs
2 Generates income for people living in these areas
3 Creates business opportunities for travel agents
and tour operators
Advantages of Fossil Tourism
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Terminology
Fossils are remains of ancient life forms preserved in rock
Paleontology is the study of fossils
Petrify this means to turn into stone
Imprints are left behind when the organisms start to decay before it becomes petrified
Strata are the in layers in which sedimentary rock pile up
Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Terminology
Amber is the hardened form of liquid sap
Relative dating finds the age of the fossil by comparing it to another fossil or geological event
Radiometric dating tries to find out how long ago a particular fossil was formed
Stromatolites are dome-shaped mat like layers of rock
Fossil tourism is a type of ecotourism where the main attraction is its fossils
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Something for your to do
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A AmberB TarC SappedD Ice
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative datingB PaleontologyC TimingD Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative datingB PaleontologyC TimingD Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A RelativeB RadioactiveC RadiometricD Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
6 The strange looking fish once thought to be extinct over 70 million years ago
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa
A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
8 The skull and skeleton of the Euskelosaurus is found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
11 The fossils of soft bodied invertebrates have been found inhellip
A LadybrandB BarbertonC Northern CapeD Eastern Cape
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
12 The fossils of the most primitive mammal like reptiles were found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
13 Dinosaur bones were located inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
14 The worldrsquos richest concentration of fossils occur inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
15 The fossils of 650 million year old sponges have been found inhellip
A MalutiB KarooC Northern NamibiaD Western Cape
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
16 Early dinosaur found in Ladybrand that was a herbivore
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
18 A reptile that gave rise to mammals
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
19 Cone bearing plant found in Mooi River nearly 280 million years ago
A LystrosaurusB GlossopterisC EuskelosaurusD Octavia
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
20 World heritage sitehellip
A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Solution
1 A
2 D
3 A
4 B
5 C
6 A
7 B
8 A
9 D
10 B
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Solution
11 C
12 B
13 A
14 D
15 C
16 C
17 D
18 A
19 B
20 A
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 1 of 12
Fossil formation and methods of dating
1 What are fossils
Fossils are the mineralized remains of animals or plants or other traces such as footprints
All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the
fossil record
The study of fossils is called palaeontology
The richest sources of fossils are found in sedimentary rock
2 How are fossils formed
The following sets of diagrams and annotations (notes) explain how fossils form
The organism (ammonite in this example) dies
Sand and silt from the land is carried to the seas and swamps by rivers
The remains of dead organisms settle to the bottom of the river swamp ocean floor
An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified
Imprints are just outlines of the dead organism or parts of it left in the stone
Numerous mineral salts also settle to the bottom of the river swamp ocean floor
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 2 of 12
The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg
skeleton
These mineral salts then filter into the body of the dead organism
The organism becomes petrified this means that it turns into stone
Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or
imprints left behind
3 Sedimentary rock
The sedimentary rock piles up over each other over millions of years
They pile up in layers called strata
The oldest layer is at the bottom and the youngest layer at the top
Certain fossils were found in certain layers
This means that these fossils were formed in a particular period of time
4 What are Index fossils
Index fossils give an indication of the time period in which they were formed
The index fossils have a wide geographic distribution
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 3 of 12
This means that they are found in a large number of places
5 Examples of fossils
bull bones of vertebrates
bull shells exoskeletons of invertebrates
bull tracks (footprints)
bull burrows
bull hardened faeces of animals
bull petrified tree trunks
bull imprints of leaves and small animals
Different forms or types of fossils
ammonite fossils
Petrified cone of Araucaria sp from
Patagonia Argentina dating from
the Jurassic Period (approx 210 Ma)
Eocene fossil fish Priscacara liops Petrified wood
from Green River Formation of Utah
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 4 of 12
Lower Proterozoic Stromatolites from Bolivia
South America
Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer
of sediment and other precipitants[3]
A fossil gastropod from the Pliocene of Cyprus
A serpulid worm is attached
Megalodon and Carcharodontosaurus teeth The latter
was found in the Sahara Desert
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 5 of 12
Permineralization
External mold of a bivalve from the
Logan Formation Lower Carboniferous Ohio
Recrystallized scleractinian coral
(aragonite to calcite) from the Jurassic of southern Israel
Resin fossils
Leptofoenus pittfieldae trapped in Dominican
amber from 20-16 million years ago
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 6 of 12
Skeleton of whale that walked on land found in Pakistan
6 Other types of fossils
Remember fossils also occur in tar and ice Here are some examples of such fossilshellip
fossils of the woolly mammoth were found frozen in ice
pits of tar contained bones of the sabre toothed cats
some insects have been found in amber Amber is the hardened form of liquid sap of plants
Generally five types of fossils are recognised
bull Mould fossil
bull Cast fossil
bull Trace fossil
bull True form fossil
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 7 of 12
7 Determining the age of fossils
There are two methods used to determine the age of fossils
These are
relative dating and
radiometric dating
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 8 of 12
8 Relative dating
In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event
Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event
It does not give the exact age of the fossil
An example of geological event is a volcanic eruption
If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer
was formed before the one found in the upper layer
This does not tell us the exact age of the fossil
If the original layering is upset it is not so easy to compare the age of one fossil to another
Scientists are able to use index fossils
If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell
the rock actually came from a lower layer
the original layering was upset by a geological event
the new fossil was formed before the other fossils
9 Radiometric dating
Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and
accurate than the Relative dating method
Radiometric dating means
radio comes from the word radioactive
Metric simply refers to measurement
Dating refers to the process of finding out the age of the fossil
Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful
because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a
fixed rate
Activity 4
1 The solid formed from the hardening of the liquid sap of trees is calledhellip
A Amber
B Tar
C Sapped
D Ice
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 9 of 12
2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip
A Relative dating
B Paleontology
C Timing
D Radiometric dating
3 The process of finding out the ages of fossils by comparison with another fossil or rock
A Relative dating
B Paleontology
C Timing
D Radiometric dating
4 Substances which give of nuclear radiation and decay into other substances are calledhellip
A Relative
B Radioactive
C Radiometric
D Reactive
5 The group name given to the first life forms which developed on Earth about 38 billion years ago
ishellip
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
6 The strange looking fish once thought to be extinct over 70 million years ago
A Coelacanth
B Glossopteris
C Photosynthetic bacteria
D Euskelosaurus
7 A skull and skeleton of the Euskelosaurus was found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 10 of 12
8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 11 of 12
9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
10 Fossils of soft bodied invertebrates have been found in or near hellip
A Ladybrand
B Barberton
C Northern Cape
D Eastern Cape
11 The fossils of the most primitive mammal like reptiles were found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
12 Dinosaur bones were located in or nearhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
13 The worldrsquos richest concentration of fossils occurs inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
14 Fossils of 650 million year old sponges have been found inhellip
A Maluti
B Karoo
C Northern Namibia
D Western Cape
15 Name of an early dinosaur found in Ladybrand that was a herbivore
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban
Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5
Page 12 of 12
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
17 A reptile that gave rise to mammals
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
18 Cone bearing plant found in Mooi River nearly 280 million years ago
A Lystrosaurus
B Glossopteris
C Euskelosaurus
D Octavia
19 This area has been declared a World heritage sitehellip
A Cradle of Humankind
B West Coast Fossil Park
C Mooi River
D Durban