Darwin’s Theory of EvolutionDarwin Presents his Case
Chapter 15-3
In 1858 another naturalist,_________________, wrote anessay describing his work in _______
thatsummarized the same ideas _____ hadbeen thinking about for 25 years!
Alfred Russel WallaceMalaysia
Darwin
Suddenly Darwin had incentive to publish
the results of his work!
In 1859____________________presented _______ and proposed a________ for evolution that he called__________________
On the Origin of Speciesevidence
mechanism
NATURAL SELECTION
A theory is a ____________, _______, explanation of phenomena that have occurred in the natural world, like the theory of __________________, ________, and _____________.
well-supported testable
gravitational attractioncell theory atomic theory
Isn’t evolution just a theory?
WHAT IS DARWIN’S THEORY?
_________________ is found naturally in all populationsGENETIC VARIATION
WHAT IS DARWIN’S THEORY?______________________means that members of each
species must ________ for food, space, and other __________.
STRUGGLE FOR EXISTANCE
COMPETERESOURCES
WHAT IS DARWIN’S THEORY?Some organisms in a ________are ________ to survive.
populationless likely
WHAT IS DARWIN’S THEORY?_____________________organisms which are better adapted to the environment will ______ and________, passing on their _____.
SURVIVAL OF THE FITTEST
survivereproduce genes
VOCAB Ability of an individual to __________________ in its specific environment = ______fitness
surviveand reproduce
VOCAB Any ___________________ thatincreases an organism’s ______________ = _____________ADAPTATION
inherited characteristicchance of survival
Over time, natural selectionresults in ________ in theinherited characteristics of a __________.
These changes ______ aspecies’ _____ in its environment.
WHAT IS DARWIN’S THEORY?
CHANGES
POPULATION
increasefitness
How Does Evolution Really Work?
____________________________suggests that each species has ___________, with ________,from other species over time.
This idea suggests that all living species are ____________________, and that all species, living and extinct,share a _________________.
WHAT IS DARWIN’S THEORY?DESCENT WITH MODIFICATION
DESCENDED CHANGES
RELATED TO EACH OTHER
COMMON ANCESTOR
EVIDENCE OF EVOLUTION:1.________________2.________________3. _______________4. _______________5. _______________6. _______________7. _______________
Fossil recordGeographic DistributionHomologous structuresEmbryology
DNASee Natural selection happen
Artificial selection
ARTIFICIAL SELECTION WORKSIn artificial selection, ____________provides the _________ through_________ and _________________and ______________ those traits that they find ______.
NATUREvariation
mutation sexual reproductionhumans select
useful EX: We have selected for and bred cows to produce more milk,turkeys with more breast meat, etc.
Breeds of Dogs
Chihuahua – bred from Techichi of Mexicoby Mayans, had religious significance
Saint Bernard – bred by monks around 1050 A.D. to rescue travelers of mountain passes in the
Swiss Alps between Italy and Switzerland
Irish Wolfhound – bred in Ireland to hunt wolves and elk
Dachshund – bred in Germany as earlyas the 15th century to hunt badgers
____________________________ARTIFICIAL SELECTION WORKS
How Do We Know Evolution Happens?
2. The Fossil Record – ______ are the ________________________found in layers of rock in the Earth.
Fossilsof ancient organisms
remains
How Do We Know Evolution Happens?The layers of rock tell the history of the_____, while the _____ found withinthe rock tell a history of ___.
The fossils are thought to be the ________ as the rock theyare found in.
Earth fossilslife
same age
Go to Section:
Sea level
Sedimentary rocks form in horizontal layers.
When part of Earth’s crust is compressed, a bend in a rock forms, tilting the rock layers.
As the surface erodes due to water, wind, waves, or glaciers, the older rock surface is exposed.
Movement of Earth’s CrustSection 15-2
Fish die inthe oceanand arecovered insediment.Over timeand underincreasingpressure,the remainsbecomesfossilized
Earthquakes and volcanoescause uplifting of the layers of the
Earth, taking the fossils along
Fossils ofmarinefish foundon themountain-sides ofsouthwestWyoming,which atone timewas covered by aninland sea
TRANSITIONAL FOSSILS HAVE BEEN FOUND
Scientific American; Dec 2005; Vol 293; p100-107
TIK-TAALIKTIK-TAALIKIntermediate between fish and early tetrapods
Fins have basic wrist bones and simple fingersEarliest fish with a neck
Discovered by Neil Shubin and Ted Daeschler in 2004
Fossil record shows change
over time
SD dinosaur fossils
If Darwin’s theory is correct you would expect to find ____________ yet _______________ living in a _________ region as they spread into nearby habitats and evolve.
different speciesclosely related
geographic
That’s EXACTLY what we do see!
REMEMBER THE GALAPAGOS TORTOISEShttp://www.newtonswindow.com/problem-solving.htm
Little vegetationLong necks
Lots of vegetationShort necks
Intermediate vegetationIntermediate necks
Tortoises adapted to different habitats as they spread from the mainland to the different islands.
= DIVERGENT EVOLUTION = ADAPTIVE RADIATION
GALAPAGOS FINCHES
The _____ of Galapagos finches have ______ to eating a _____ of _____.
http://images.encarta.msn.com/xrefmedia/aencmed/targets/illus/ilt/T014608A.gif
beaksadapted variety foods
If Darwin’s theory is correct you would also expect to find _______________ living in ________ geographic regionsbut similar habitats becoming ________ as they adapt to ______________.
far apartdifferent species
more alike
That’s EXACTLY what we do see!
similar ecosystems
Whales and sharks have a _____ body designeven though they are very _______ organisms (one is a fish; the other, a mammal)because they have _________________ to living in a _____ environment.
= CONVERGENT EVOLUTION
similardifferent
independently adaptedsimilar
Whales are closely related to wolves, but don’t look or act much like them = divergent evolution
Whales are distantly related to sharks, but look and act morelike them =convergent evolution
Conclusion:The pressure ofthe environmentdrives evolution
Go to Section:
Figure 15–14 Geographic Distribution of Living Species
Section 15-3
Beaver
NORTH AMERICA
Muskrat
CapybaraSOUTH AMERICA
Coypu
Beaver
Muskrat
Beaver andMuskrat
Coypu
Capybara
Coypu andCapybara
Beaver and capybaraare _____________________ living in very ________ environments,while beaver and musk-rat are ______________________ living in a______ environment.Differences betweenbeaver and capybarashow _________ evolution, while similaritiesbetween beaver andmuskrat show __________ evolution.
Differences between _____________ muskratand coypushow _________evolution, whilesimilarities between ______________ capybaraand coypu show___________evolution.
closely-relatedspeciesdifferent
distantly-relatedspeciessimilar
divergent
convergent
closely-related
divergent
distantly-related
convergent
4. _____________________HOMOLOGOUS Structures
4. Homologous Body Structures – Structures, like the limbs of vertebrates, look very _______, but are made from the __________, because they are made fromthe same clump of _____________ cells in the _______.
same bones
embryoundifferentiated
different
Go to Section:
Turtle Alligator Bird Mammal
Ancient lobe-finned fish
Figure 15–15 Homologous Body Structures
Section 15-3
4. Homologous Body Structures – Some _______________________are _______ and have no usefulfunction even though they are still present, like ________in whales and boa constrictors, or a ____ and ________________in humans.
homologous body structuresvestigial
hipbonestail
cecum (appendix)
Most mammals have a pouch between their small and large intestine that contains bacteria to digest plants called a _____.
In humans the cecum is shrunken and unused.
It is our _________appendix
cecum
Why grow a tail and then lose it?
HUMAN EMBRYO_________________
__________________________________Tail disappears at
has a tail at 4 weeks
about 8 weekstail
Skinks are a type of lizard. In some species, legs have become so small they _______
______ in walking. Why would an organism possess organs ___________________?One explanation:The ________ is present to make the organ, but_________________ through ______________.If the organ is not vital to survival, then natural selection would not cause its elimination.
no longerfunction
gene codechange over timefunction has been lost
little or no functionwith
5. _____________________________ of many animals with back-bones are very similar.
Similarities in EmbryologyEmbryos
It is clear that the same groups of _____________ cells develop in the same order to produce the same tissues and organs of all vertebrates, suggesting that they all _______ from a _______________.
undifferentiated
evolvedcommon ancestor
Image from: http://io.uwinnipeg.ca/~simmons/16cm05/1116/16anim3.htm
6. _______________
Similarities in ____ and ________ sequencessuggestrelatedness
Similarities in DNA
PROTEINDNA
Similar _________ suggest an ___________________.
Human- 46 chromosomes Chimpanzee- 48 chromosomes
karyotypesevolutionary relationship
1. ________________________If you take the two smaller chromosomes apes have that we don’t, and place them end to end, the ______ _______________ to the #2 human chromosome __________________.
BANDING PATTERN MATCHES
bandingpattern is identical
wehave that they don’t
2. ____________________Chromosomes have special sequences called _______ at their ends to protect the strands during replication.
TELOMERES IN MIDDLE
telomeres
2. TELOMERES IN MIDDLE Telomere sequences are found __________ and _____________________ of human chromosome #2 suggesting it was made by _____ two other chromosomes together.
→
→
→ALSO IN THE MIDDLE
at the ends
fusing
WHY DOES EVOLUTION MATTER NOW?
There is a natural variation in populations of peppered moths.
________________
___________________
7.____________________________EX: Peppered Moths
Can see Natural selection happen
Typica form - lighter
Carbonaria form - darker
Typica
Carbonaria
The ___________ form was the predominant form in England _____________________________.
Around the middle of the 19th century the ______ form began to appear. It was first reported in 1848. By 1895 98% of the moths in Manchester were the ____ variety.
In recent years, the burning of cleaner fuels and Clean Air regulations has reduced the pollution there and the ______ colored moths have increased in numbers.
light coloredprior to the Industrial Revolution
darker
dark
lighter
7.____________________________EX: Changes in disease-causing microbes that produce new organisms and __________.
_______
___
__________________________
Can see Natural selection happen
Bird flu
Antibiotic-resistant tuberculosis
HIV
new diseases
PBS EVOLUTION VIDEO CLIPSIsn’t Evolution Just a Theory? QuickTime
Who was Charles Darwin? QuickTime
How Do we Know Evolution Happens? QuickTime
How Does Evolution Really Work? QuickTime |
Why Does Evolution Matter Now? QuickTime
Why is Evolution Controversial Anyway? QuickTime