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Evolution Lectures 3: (Chapter 2 of Herron & Freeman) Patterns and Evidence of Evolution

Evolution Lectures 3: (Chapter 2 of Herron & Freeman) Patterns and Evidence of Evolution. For the purposes of this class, you must understand the theory of evolution by natural selection and how we study it in biology. Evolution = Change over time!.

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Evolution Lectures 3: (Chapter 2 of Herron & Freeman) Patterns and Evidence of Evolution

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  1. Evolution Lectures 3:(Chapter 2 of Herron & Freeman)Patterns and Evidence of Evolution

  2. For the purposes of this class, you must understand the theory of evolution by natural selection and how we study it in biology.

  3. Evolution = Change over time!

  4. On the Origin of Species by Means of Natural Selection Charles Darwin – English naturalist Published in 1859 Postulates Earth’s creatures are products of descent with modification from a common ancestor

  5. Key Elements Species (not individuals) change over time Lineages split and diverge (speciation) Over long periods of time, novel species can derive from earlier forms Species share ancestors, not independent Life (and Earth) are very old! (lots of time)

  6. Figure 2-2b

  7. Microevolution Populations of organisms change across generations (change over time) Let’s review some examples

  8. Microevolution Selective breeding (artificial, not natural selection) wolf dog dogs dog dog

  9. Selective breeding foxes for domesticity Can select not just morphology but behavior

  10. Microevolution Video on fox domestication/selection https://www.youtube.com/watch?v=0jFGNQScRNY

  11. Vestigial structures: unused/rudimentary organ that serves function in closely related organisms Figure 2-7

  12. Microevolution Stickleback fishes MARINE FRESHWATER

  13. Microevolution Stickleback fishes: lake population wiped out, 1988 marine population invades Video to check out: https://www.youtube.com/watch?v=VE2q5IhjdYM

  14. Speciation New species arise from preexisting species (common ancestors) What is a species??? Very gray area! We can consider species independently evolving populations that do not breed (usually!)

  15. Speciation More sticklebacks! Speciation starts with a single population where individuals vary In Robert’s Lake, the gillraker of the sticklebacks vary, and diet varies with this

  16. Speciation

  17. Speciation

  18. New Species Descend from Old Fossils are a window to the past, tell us much about present organisms

  19. New Species Descend from Old Archeopteryx: https://www.youtube.com/watch?v=WVtw2ylkOJA Whales: https://www.youtube.com/watch?v=o92x6AvxCFg

  20. New Species Descend from Old

  21. Evidence of Common Ancestry All life forms are related Homology connects this Some examples

  22. Evidence of Common Ancestry Homologies: the same organ in different species (that may serve different functions)

  23. Evidence of Common Ancestry Homologies: the same organ in different species (that may serve different functions)

  24. Evidence of Common Ancestry BUT! The same function in different organisms does not mean something is homologous (convergence)

  25. Shared Ancestry Descent with modification from a common ancestor predicts extant organisms should share nested sets of novel traits Video here with excellent explanation (molecular convergence) https://www.youtube.com/watch?v=guh837QJIiA Start at hour ~ 1.44

  26. Age of the Earth Evidence for Pangea Plate tectonics Radio dating Descent with modification is slow…

  27. Age of the Earth Radiometric dating https://www.youtube.com/watch?v=phZeE7Att_s Plate tectonics: https://www.youtube.com/watch?v=KB7HzF2O3Kg

  28. Evolution Lectures 3:(Chapter 2 of Herron & Freeman)Patterns and Evidence of Evolution

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