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Evolution happens. We are going to look at the evidence that supports this and also look at some of the different ways that evolution happens.
One of the "keystones" of the evidence of evolution is the idea of a common ancestry to all life on the planet. Once upon a time there was one type of life ..... and over the millennia this one form of life has become the variety of life we have now. What points to this?? - DNA! All of the life on our planet has DNA - the universal genetic code is found in all living things. Its the thread that binds our "family" tree together.
Step 1 (a) : Here is one version (there are a few) of our "family" tree. Take the time to explore the branches - where do we fit. What do you think has led to the complicated forms of life we find now? This is part of the portfolio of information you need to have and understanding of. (Learn)
Evidence for evolution isn't just found in our DNA. There are other pieces of evidence that we need to add to our portfolio.
Step 1 (b) : Here is a diagram that summarises many of the pieces of evidence that point to evolution happening. Take some time to get a bit more familiar with what they are. (Learn)
One of the items of evidence listed in the above diagram, is the piece of evidence that started the journey of evolutionary studies.
Fossils - the preserved remains of past organisms. So how do they form?
Step 1 (c) : Have a look at this diagram - a lot of things have to happen in order for a fossil to form. Hopefully now you'll under stand why they aren't more common. (Learn)
So you've found a fossil ..... now you need to interpret the story its trying to tell us. So how does the fossil and the rock it was found in tell us what we would like to know?
Step 1 (d) : Read the information found in the following 2 diagrams. (Learn)
Sometimes we are lucky enough and find a fossil that appears to provide a link between two uther types of fossils thought to be quite different eg reptiles and birds.
Step 1 (e) : Have a look at this famous Transitional Fossil of Archaeopteryx. (Learn)
Sometimes (but seldom) we find a nearly complete record of fossils form the ancestral species to what is alive today. Horses and whales are two such examples.
Step 1 (f) : Have a look at their fossil records. (Learn)
Mission 1 : Okay taking what you now know about fossils read and complete the section of work on "Evidence for evolution - Fossils". (Learn)
Done that? = Share with your teacher.
Yes = now its time for your next Step/Video clip/Challenge/Mission.
No = go back and complete the Step/Video clip/Challenge/Mission please.
So we have fossils - hard to create and hard to find. But there are living creatures all around us - they also have an evolution story to tell. The pattern of where we find different but related species today tell not only a biological story but also a geographical story. Using plate tectonics and geological time, or island hopping, we have a branch of Science called Biogeography.
Step 2 : Have a look the following diagram. (Learn)
Mission 2 : So now take the above information and what have watched in the video plus what you have in your workbook complete the "Evidence for Evolution - Biogeography" section. (Learn)
Done that? = Share with your teacher.
Yes = now its time for your next Step/Video clip/Challenge/Mission.
No = go back and complete the Step/Video clip/Challenge/Mission please.
The "Pentadactyl" limb is a great example of nature creating a structure and then "modifying" it for a wide variety of habitats. We call this reuse of the same basic structure - homologation. SO homologous structures are actually the "same" thing just modified for a different purpose.
Step 3 : Have a look at the diagram ... (Learn)
Mission 3 : So taking the information found here, plus what you can read in your books answer the questions on "Evidence for Evolution - Comparative Anatomy". (Learn)
Done that? = Share with your teacher.
Yes = now its time for your next Step/Video clip/Challenge/Mission.
No = go back and complete the Step/Video clip/Challenge/Mission please.
So if Homologous structures are just the same thing - but adapted for different uses. What about Analogous structures?
These are structures that perform similar functions but have completely different origins e.g. the wings on birds, bats and insects all allow them to fly but have com about in completely different ways.
Step 4 : Have a look at these clips to hopefully clarify this. (Learn)
Mission 4 : See how you get on with the questions on "Analogous Structures" in your workbook. (Learn)
Done that? = Share with your teacher.
Yes = now its time for your next Step/Video clip/Challenge/Mission.
No = go back and complete the Step/Video clip/Challenge/Mission please.
Yet more structures .... Vestigial Structures are evidence of our evolutionary journey. They are structures that serve no function today - but were used at some in our evolutionary past.
Step 5 : Have a look at these "left overs" - what vestigial bits do you have = evidence from the past. (Learn)
Mission 5 : Read and complete the work on "Vestigial Structures" in your workbooks. (Learn)
Done that? = Share with your teacher.
Yes = now its time for your next Step/Video clip/Challenge/Mission.
No = go back and complete the Step/Video clip/Challenge/Mission please.
With the increased knowledge of DNA we can now "Measure" how long ago changes took place - the more differences two species have in their DNA = the longer ago they shared a common ancestor.
It is best seen in what are called highly conserved DNA = changes very little with time.
Step 6 : Have a look at the information here - remember its not THE answer .... but is one the tools we can use to help us find an answer. (Learn)
Mission 6 : Now also read the "Evidence for Evolution - Molecular Biology" and "Evidence from mtDNA and Y Chromosome anaylsis" pages and complete the questions there. (Learn)
Done that? = Share with your teacher.
Yes = now its time for your next Step/Video clip/Challenge/Mission.
No = go back and complete the Step/Video clip/Challenge/Mission please.
We are quite used to the idea of things getting more different of time = diverging. But when put into similar environments different things can get more similar = converge.
Step 7 : Have a look as the following clip explains this with regards to evolution. (Learn)
Mission 7 : Time to see what you understand about all that - read and complete the "Patterns of Evolution - Divergent and Convergent Evolution" section in your workbooks. Now apply this information to the 'Animals of the world collectors cards' page.(Learn)
Done that? = Share with your teacher.
Yes = now its time for your next Step/Video clip/Challenge/Mission.
No = go back and complete the Step/Video clip/Challenge/Mission please.
Evolution happens due to environmental pressure to change (no pressure = no change) in order to survive.
So if/when a species arrives in an new habitat with a variety of vacant niches - we find that that the one original species tries to occupy as many of these niches as possible. However the organism will need to change (evolve) to be better suited to survive in that niche. eventually the one original species becomes many new species. We call this "burst" of evolution "Adaptive Radiation".
Step 8 : Have a look as this is explained to you. (Learn)
Mission 8 : Your workbook also explains it to you. So read and complete the work on Adaptive Radiation and a great NZ example Adaptive Radiation - The Moa. (Learn)
Done that? = Share with your teacher.
Yes = now its time for your next Step/Video clip/Challenge/Mission.
No = go back and complete the Step/Video clip/Challenge/Mission please.
What came first - the bee or the flower? Or, amazing predator eyesight and crazy good camouflage?
The next evolution concept is known as Coevolution : this happens between 2 unrelated but interacting species. One develops some adaptive advantage over the other (eg, predator gets faster) this then put selective pressure on the other (the slowest prey get eaten). This results in the fastest prey surviving = predator needs to get faster still = prey gets faster ....... We have coevolution.
Step 9 : Here are some more explanations of what coevolution is. (Learn)
Mission 9 : Read and complete the page in your workbook on Patterns of Evolution - Coevolution. (Learn)
Darwins Orchids - this is a good story about orchids that Darwin didn't find and moths that he said should exist but weren't found until after he had died. Perhaps an extreme example of coevolution.
Have a look at this clip. (Learn)
Mission 9 (a) : Now read and complete the work on Darwin's Orchid in your workbooks. (Learn)
Done that? = Share with your teacher.
Yes = now its time for your next Step/Video clip/Challenge/Mission.
No = go back and complete the Step/Video clip/Challenge/Mission please.
So how fast does evolution happen? There is evidence for both fast and slow patterns of evolution - this has led to two main models of evolution. Both of these have likely been in operation at different times. So we have Gradualism and Punctuated Equilibrium. Both lead to new species being formed.
Step 10 : Watch here as these 2 models are explained. (Learn)
Mission 10 : Now read and complete the pages on The Rate of Speciation. (Learn)
Done that? = Share with your teacher.
Yes = now its time for your next Step/Video clip/Challenge/Mission.
No = go back and complete the Step/Video clip/Challenge/Mission please.
Final Mission : Using the information you now have answer the end of topic review questions on Patterns of Evolution. (Learn)
This is the end of all the work on evolution - here is a summary of hopefully the most up to date information about what we know about evolution ...... Hopefully it works for you = let me know if not.
BIOZONE Human Evolution Talk VCE 2020.pdfReport abuse