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Published byMark Augustus Dean Modified over 9 years ago
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Evidence for Evolution A slide extravaganza…
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Types of evidence… z1. Evidence from the fossil record (dead things)
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Fossil formation zBones and shells undergo mineral replacement and are turned into rock zSoft material either disappears, or leaves an impression in the earth (that turns to rock)
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A selection of fossils…
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Fossils show transitions The Archaeopterix -- between reptile and bird
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Scallops
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From early to modern horse
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(Living things show transitions too)
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Coelacanths - “the living fossil”
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Types of evidence… z1. Evidence from the fossil record
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Types of evidence… z1. Evidence from the fossil record z2. Comparative Anatomy
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A. Homologous Structures Homo - logy Homologous structures have the same underlying forms
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Wing anatomy comparison And compared to our arm…
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Arm anatomy comparison
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B. Analogous Structures Ana - logy Analogous structures have a similar outward appearance (but different underlying forms)
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Types of evolution Convergent evolution Distantly related organisms evolve similar external features Divergent evolution A common ancestor gives rise to organisms that evolve for different environments
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Which goes with which? …. Homologous structures Analogous structures Convergent evolution Distantly related organisms evolve similar external features Divergent evolution A common ancestor gives rise to organisms that become more different with time.
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Which goes with which? Homologous structures Analogous structures Convergent evolution Distantly related organisms evolve similar external features Divergent evolution A common ancestor gives rise to organisms that become more different with time.
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C. Vestigial Structures Vestige - a left-over/ remnant Vestigial structures are evolutionary “leftovers” from an earlier ancestor
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The “dew” claw of a wild cat
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The human appendix Rabbit Fetal Human Adult Human
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Membranes in our eyes
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Hip bones in whales (Look at that “hand” too!)
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Types of evidence… z1. Evidence from the fossil record z2. Comparative Anatomy
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Types of evidence… z1. Evidence from the fossil record z2. Comparative Anatomy z3. Comparative Embryology
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Human embryo at 5 weeks
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Embryos… …can you guess which one is human?
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…how about now? Embryos…
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And now… Were you right?
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Types of evidence… z1. Evidence from the fossil record z2. Comparative Anatomy z3. Comparative Embryology
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Types of evidence… z1. Evidence from the fossil record z2. Comparative Anatomy z3. Comparative Embryology z4. Molecular Evidence
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Comparing DNA…
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Determining relationships DNA similarity between species is used to determine how closely related they are. This is in turn used to construct possible evolutionary trees.
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How closely related are these fellows? Giant Panda Brown Bear Mystery critter! (I’m not telling) …got your guess?
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An Evolutionary Tree …so why is he called a red panda? This tree was constructed by looking at % similarity of DNA among “bears”
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Types of evidence… z1. Evidence from the fossil record z2. Comparative Anatomy z3. Comparative Embryology z4. Molecular Evidence
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Types of evidence… z1. Evidence from the fossil record z2. Comparative Anatomy z3. Comparative Embryology z4. Molecular Evidence z5. Behavior
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Behavioral similarities zDuck and other bird mating dances zHow primates carry their young zFish swimming motions and salamander walks zAnd on and on and on….
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Types of evidence… z1. Evidence from the fossil record z2. Comparative Anatomy z3. Comparative Embryology z4. Molecular Evidence z5. Behavior
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Types of evidence… z1. Evidence from the Fossil Record z2. Comparative Anatomy z3. Comparative Embryology z4. Molecular Evidence z5. Behavior z6. Direct observation also known as microevolution
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Artificial selection Remember us?
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And look at us!
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And Natural Selection Hawaiian Rock Wallabies!
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The Beak of the Finch zBiologists Peter and Rosemary Grant documented natural selection occurring in populations of finches on the Galapagos islands over a period of only 20 years! This generation to generation changes in the frequency of certain traits is called microevolution.
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