bioknowledgy 5.1 evidence for evolution
TRANSCRIPT
Essential idea: There is overwhelming evidence for the evolution of life on Earth.
By Chris Paine
https://bioknowledgy.weebly.com/http://images.nationalgeographic.com/wpf/media-live/photos/000/009/custom/993_1280x1024-wallpaper-cb1425504376.jpg
This image of a fossilised primitive vascular plant called a horsetail. Fossils are just one example of evidence for evolution along with homologous structures, the universality of DNA, and antibiotic resistance.
5.1 Evidence for evolution
Understandings, Applications and Skills
Statement Guidance
5.1.U1 Evolution occurs when heritable characteristics of a
species change.
5.1.U2 The fossil record provides evidence for evolution.
5.1.U3 Selective breeding of domesticated animals shows
that artificial selection can cause evolution.
5.1.U4 Evolution of homologous structures by adaptive
radiation explains similarities in structure when
there are differences in function.
5.1.U5 Populations of a species can gradually diverge into
separate species by evolution.
5.1.U6 Continuous variation across the geographical range
of related populations matches the concept of
gradual divergence.
5.1.A1 Development of melanistic insects in polluted
areas.
5.1.A2 Comparison of the pentadactyl limb of mammals,
birds, amphibians and reptiles with different
methods of locomotion.
http://www.johnkyrk.com/evolution.html
5.1.U1 Evolution occurs when heritable characteristics of a species change.
Evolution occurs by the mechanism of natural selection (see topic 5.2)
“… but, evolution is just a theory …”
http://youtu.be/1uzsuCFUQ68
Why science is NOT 'Just a Theory'
Evolution: It's a Thing
http://youtu.be/P3GagfbA2vo
Despite the strength of evidence there is still widespread disbelief of evolution among some religious groups.
http://youtu.be/dw4w1UsOafQ
Richard Dawkins - Growing up in the Universe
Watch the videos to learn more about theories, evolution and the evidence supporting evolution.
1 hour long, but worth it
5.1.U2 The fossil record provides evidence for evolution.
http://www.pbs.org/wgbh/nova/evolution/fossil-evidence.html
5.1.U2 The fossil record provides evidence for evolution.
http://commons.wikimedia.org/wiki/File:First_Dinosaur_Tracks_from_the_Arabian_Peninsula.jpghttp://commons.wikimedia.org/wiki/File:Knightia_eocaena_FBNM.JPG|
2. Indirect (trace fossils) such as footprints, tooth marks, tracks, burrows, etc.
A fossil is the preserved remains or traces of any organism from the remote past
Fossil evidence may be one of two types:
1. Direct (body fossils) such as bones, teeth, shells, leaves, etc.
http://www.gridclub.com/subscribers/info/fact_gadget_2009/images/pl1co1f1.jpg
5.1.U2 The fossil record provides evidence for evolution.
The fossil record is the sum of all discovered and undiscovered fossils and their relative placement in rock.
The fossil record provides the dimension of time to the study of evolution – the layer of rock in which a fossil is found can be dated and therefore used to deduce the age of the fossil.
http://commons.wikimedia.org/wiki/File:Fossils_in_a_beach_wall.JPG
http://sciencelearn.org.nz/Contexts/Dating-the-Past/Sci-Media/Images/Fossils-in-sedimentary-rock
5.1.U2 The fossil record provides evidence for evolution.
The fossil record is the sum of all discovered and undiscovered fossils and their relative placement in rock.
The fossil record provides the dimension of time to the study of evolution – the layer of rock in which a fossil is found can be dated and therefore used to deduce the age of the fossil.
http://commons.wikimedia.org/wiki/File:Fossils_in_a_beach_wall.JPG
http://sciencelearn.org.nz/Contexts/Dating-the-Past/Sci-Media/Images/Fossils-in-sedimentary-rock
5.1.U2 The fossil record provides evidence for evolution.
The fossil record clearly shows changes (in characteristics) of organisms
Fossils show a chronological (time) sequence in which characteristics appear and develop in complexity
http://commons.wikimedia.org/wiki/File:Equine_evolution.jpg
5.1.U2 The fossil record provides evidence for evolution.
The fossil record clearly shows changes (in characteristics) of organisms
Fossils show a chronological (time) sequence in which characteristics appear and develop in complexity
Fossils have been discovered of many types of organism that no longer exist, e.g. trilobites and dinosaurs.
In most cases no fossils can be foundof organisms that do exist today.
This suggests that the ancestral species evolved into the modern species
http://commons.wikimedia.org/wiki/File:Equine_evolution.jpg
5.1.U2 The fossil record provides evidence for evolution.
Transitional fossils show the links between groups or species by exhibits traits common to both the ancestral group/species and its derived descendant group/species.
Archaeopteryx is a famous example transitional fossils – it gives evidence for the evolution of birds from dinosaurs.
http://commons.wikimedia.org/wiki/File:Archaeopteryx_lithographica_%28Berlin_specimen%29.jpg
http://commons.wikimedia.org/wiki/File:Archaeopteryx_NT.jpg
Bird features:• feathers
Dinosaur features include:• jaws with sharp teeth• three fingers with claws• long bony tail
5.1.U3 Selective breeding of domesticated animals shows that artificial selection can cause
evolution.
Examples:
• Breeding dogs for herding, e.g. sheepdogs or racing, e.g. greyhounds
• Cows are bred for milk yield or meat
• Crops have been bred for increased yield and/or disease resistance
Selective breeding (also called artificial selection) is the process by which humans breed animals and plants for particular traits
http://commons.wikimedia.org/wiki/File:Greyhound_Racing_2_amk.jpghttp://commons.wikimedia.org/wiki/File:Canis_lupus_baileyi_running.jpg
http://www.pbs.org/wgbh/harvest/engineer/select.html
5.1.U3 Selective breeding of domesticated animals shows that artificial selection can cause
evolution.
Selective breeding (also called artificial selection) is the process by which humans breed animals and plants for particular traits
Individuals which show the most desirable traits are chosen to breed together.
Individuals which do not show the desired traits are not allowed to breed.
The next generation will have an increased frequency of the desired trait.
The process is repeated for many generations until the entire population shows the desired trait
Domestic breeds show great variation compared to wild populations populations subject to only natural variation.
http://teewallpapers.net/wp-content/uploads/2014/12/popular-dog-breeds-1.jpg
Populations show variation in traits
5.1.U4 Evolution of homologous structures by adaptive radiation explains similarities in structure
when there are differences in function.
comparative anatomy of groups of animals or plants shows certain structural features are basically similar. Structures or anatomical features having similar basic structure as in other species said to be homologous.
homologous structures are those that are similar in shape in different types of organisms
The structural similarities imply a common ancestry
homologous structures used in different ways in different species
This illustrates adaptive radiation since the basic structure adapted to different niches
The more exclusive the shared homologies the closer two organisms are related.
http://en.wikipedia.org/wiki/File:Homology_vertebrates-en.svg
The tale of the limb
http://evolution.berkeley.edu/evolibrary/article/0_0_0/similarity_hs_02
5.1.A2 Comparison of the pentadactyl limb of mammals, birds, amphibians and reptiles with
different methods of locomotion.
The pentadactyl limb in vertebrates is an example of a
homologous structure
http://commons.wikimedia.org/wiki/File:Evolution_pl.png
5.1.A2 Comparison of the pentadactyl limb of mammals, birds, amphibians and reptiles with
different methods of locomotion.
The pentadactyl limb in vertebrates is an example of a
homologous structure
It is adapted to different mode of locomotion in particular environment.
• dolphin fin for swimming• bat wing for flying• monkey hand for grasping• horse hoof for galloping
http://commons.wikimedia.org/wiki/File:Evolution_pl.png
5.1.A2 Comparison of the pentadactyl limb of mammals, birds, amphibians and reptiles with
different methods of locomotion.
The pentadactyl limb in vertebrates is an example of a
homologous structure
http://commons.wikimedia.org/wiki/File:Evolution_pl.png
NoS: Despite the obvious differences all the organisms share the same bones. For example the bones may vary in size and shape, but all vertebrates have five fingered ‘hands’ at the end of each limb.
5.1.U5 Populations of a species can gradually diverge into separate species by evolution.
http://evolution.berkeley.edu/evosite/evo101/VBDefiningSpeciation.shtml
If populations, e.g. fruit flies, become separated (e.g. a population is blown by a storm to a distant island). Then it is very likely the population will experience different ecological conditions.
Over many generations the shape of the flies, food preference, mating rituals etc. will likely diverge as the result of natural selection.
If the island fruit flies migrate back to the mainland they will not easily mate with the mainland flies as:• Mating rituals are
different• Because of genetic
differences the resulting offspring are infertile
Because genes cannot flow between the populations the island fruit flies are said to have evolved into separate
species (this process is called speciation).
1
2
3
4
n.b. islands often have many endemic (unique to that island) species due to the fact that island environments can easily cause species to become separated.
5.1.U5 Populations of a species can gradually diverge into separate species by evolution.
There are many examples of speciation. Darwin famously used the example of the finches on the Galapagos islands.
http://fhs-bio-wiki.pbworks.com/w/page/24002829/Evidence%20-%20geographical%20distribution
http://www.sepa.duq.edu/finches.html
5.1.U6 Continuous variation across the geographical range of related populations matches the
concept of gradual divergence.
Q - which of these birds are the same species and which are different species?
http://en.wikipedia.org/wiki/File:Lagopus_lagopus_Alaska_2.jpg
http://en.wikipedia.org/wiki/File:Ptarmigan9.jpg
http://www.western-isles-wildlife.com/photogallery/Red%20Grouse%20Lewis%2008%20crop.jpghttp://www.wildaboutbritain.co.uk/gallery/files/9/2/4/DSC_0014copy.jpg
5.1.U6 Continuous variation across the geographical range of related populations matches the
concept of gradual divergence.
Q - which of these birds are the same species and which are different species?
http://en.wikipedia.org/wiki/File:Lagopus_lagopus_Alaska_2.jpg
http://en.wikipedia.org/wiki/File:Ptarmigan9.jpg
Willow Ptarmigan(female) Willow Ptarmigan
(male)
Red grouse(male)
Red grouse(female)
http://www.western-isles-wildlife.com/photogallery/Red%20Grouse%20Lewis%2008%20crop.jpghttp://www.wildaboutbritain.co.uk/gallery/files/9/2/4/DSC_0014copy.jpg
5.1.U6 Continuous variation across the geographical range of related populations matches the
concept of gradual divergence.
http://en.wikipedia.org/wiki/File:Lagopus_lagopus_Alaska_2.jpg
http://en.wikipedia.org/wiki/File:Ptarmigan9.jpg
http://www.western-isles-wildlife.com/photogallery/Red%20Grouse%20Lewis%2008%20crop.jpghttp://www.wildaboutbritain.co.uk/gallery/files/9/2/4/DSC_0014copy.jpg
Populations will gradually diverge over time and it is natural to see continuous variation across a geographical range.
It is a common problem in classification to determine when two populations of one species to have sufficiently diverged to become two separate species.
The Red Grouse and the Willow Ptarmigan where at one time classified as two separate species. The current scientific consensus is that they are both members of the same species (Lagopus lagopus)
The greater the geographical separation and the longer the populations have been separated the greater the divergence.
5.1.A1 Development of melanistic insects in polluted areas.
http://i.telegraph.co.uk/multimedia/archive/02077/peppered-moth_2077529i.jpg
Variation: Peppered moths (Biston betularia) moths are found in two forms:
Normal environment: In unpolluted areas tree branches are covered in pale colouredlichens camouflage for the paler form (insularia).
The dark form (carbonaria) is normally very rare.
The moths fly at night to try to find a mate, but, during the day they rest on the branches of trees.
Selective pressure: Predation from birds (and other animals) whilst resting
Environmental change: sulphur dioxide pollution kills the lichens and soot (from coal burning) blackens the tree branches.
Result: the dark moths are well camouflaged from birds against dark tree branches are many survive to reproduce, but light coloured moths are easily found and predated by birds, few survive to reproduce.
Evolution: over a number of generations the dark (carbonaria) form of the peppered moth has increased with frequency - the heritable characteristics of the population have changed.
http://peppermoths.weebly.com/
5.1.A1 Development of melanistic insects in polluted areas.
http://i.telegraph.co.uk/multimedia/archive/02077/peppered-moth_2077529i.jpg
Variation: Peppered moths (Biston betularia) moths are found in two forms:
Normal environment: In unpolluted areas tree branches are covered in pale colouredlichens camouflage for the paler form (insularia).
The dark form (carbonaria) is normally very rare.
The moths fly at night to try to find a mate, but, during the day they rest on the branches of trees.
Selective pressure: Predation from birds (and other animals) whilst resting
Environmental change: sulphur dioxide pollution kills the lichens and soot (from coal burning) blackens the tree branches.
Result: the dark moths are well camouflaged from birds against dark tree branches are many survive to reproduce, but light coloured moths are easily found and predated by birds, few survive to reproduce.
Evolution: over a number of generations the dark (carbonaria) form of the peppered moth has increased with frequency - the heritable characteristics of the population have changed.
5.1.A1 Development of melanistic insects in polluted areas.
http://i.telegraph.co.uk/multimedia/archive/02077/peppered-moth_2077529i.jpg
Variation: Peppered moths (Biston betularia) moths are found in two forms:
Normal environment: In unpolluted areas tree branches are covered in pale colouredlichens camouflage for the paler form (insularia).
The dark form (carbonaria) is normally very rare.
The moths fly at night to try to find a mate, but, during the day they rest on the branches of trees.
Selective pressure: Predation from birds (and other animals) whilst resting
Environmental change: sulphur dioxide pollution kills the lichens and soot (from coal burning) blackens the tree branches.
Result: the dark moths are well camouflaged from birds against dark tree branches are many survive to reproduce, but light coloured moths are easily found and predated by birds, few survive to reproduce.
Evolution: over a number of generations the dark (carbonaria) form of the peppered moth has increased with frequency - the heritable characteristics of the population have changed.
http://commons.wikimedia.org/wiki/File:I%27m_a_mammal!.jpg
