Chapter 1 - The virus and the whale how scientists study evolution Biological evolution Any change in the inherited traits(gene pool of a population

Chapter 1 - The virus and the whale how scientists study...

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The virus and the whale: how scientists study evolution
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Biological evolution Any change in the inherited traits (gene pool) of a population that occurs from one generation to the next.
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Why study evolution? -to be aware of changes Why is it important to biology and what are some practical applications to understanding evolution? Practical Application: -Medical field -Wildlife fields -Agriculture
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Evolution explains the diversity of life
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Evolution case studies Whales: mammals gone to sea Viruses: the deadly escape artists
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How do we know whales are mammals? Whales share synapomorphies with mammals Mammary glands Three middle ear bones Hair (in developing embryos) Similarities with fish arose through convergent evolution
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Fossil whales share synapomorphies with modern cetaceans ecotympanic bone 50 million year old Pakicetus
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Fossils reveal links to land mammals Shape of astragalus connects to artiodactyls
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Fossil sequence documents transition from land to water
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Documenting the transition from land to water Isotopic analysis of fossil teeth Fossil analysis of hindlimb loss
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Isotopic analysis of fossil teeth Terrestrial animals drink freshwater; marine animals drink saltwater O 18 /O 16 ratio higher in saltwater Higher ratio in teeth of marine animals
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Changes in gene expression led to hindlimb loss Hindlimbs begin to form but do not fully develop Dolphin
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Research gives more clues about whale evolution Loss of teeth in baleen whales Evolution of brain size and complexity Whale diversity over evolutionary time
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  • Spring '08
  • RMAndrews
  • Evolution

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