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Evidence for Evolution

Evidence for Evolution. Chapter 21. Darwin’s Finches and Natrual Selection. What are the 3 Requirements for Natural Selection to take place?. Industrial Melanism and Peppered Moths. Selection by Predation? New Research Kettlewell

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Evidence for Evolution

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  1. Evidence for Evolution Chapter 21

  2. Darwin’s Finches and Natrual Selection • What are the 3 Requirements for Natural Selection to take place?

  3. Industrial Melanism and Peppered Moths • Selection by Predation? New Research • Kettlewell • http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/K/Kettlewell.jpg

  4. Artificial Selection • Fruit Flies • Crops • Domesticated Animals ….Pleiotropy??? • http://www.bbc.co.uk/schools/gcsebitesize/img/bidogtree.gif

  5. Fossil Evidence of Evolution • Age of Fossils can be determined • Fossils document evolutionary transition

  6. Evolution of Horses • Changes in Size • Toe Reduction • Tooth size and Shape

  7. Anatomical Evidence For Evolution • Homologous Structures…So what are analogous structures? • Vestigial Structures • Early Embryonic Development

  8. Convergent Evolution

  9. Darwin’s Critics • 1. Evolution is not Solidly Demonstrated • 2. The intelligent design argument • 3. Evolution violates the 2nd law of thermodynamics • 4.Proteins are too improbable • 5.Natural Selection does not imply evolution • 6. There are no fossil intermediates • 7. The irreducible complexity argument

  10. The Origin of Species Chapter 22

  11. The Nature of Species • Sympatric Species • Subspecies

  12. The Biological Species Concept • “ A species is a group of actually or potentially interbreeding natural population which is reproductively isolated from other such groups” • Does not explain all observations

  13. Reproductive Isolation • Geographic Isolation • Ecological Isolation • Behavioral Isolation • Temporal Isolation • Mechanical Isolation • Prevention of Gamete Fusion • Hybrid Inviability or Infertility

  14. Evolution of Reproductive Isolation • Selection May reinforce Isolating Mechanisms • Gene Flow Counters Speciation • Reinforcement - initially incomplete isolating mechanisms are reinforced by natural selection until they are completely effective

  15. Speciation • Genetic Drift • Natural Selection • Adaptation • Allopatric • Sympatric • Polypoidy

  16. Adaptive Radiation • Hawaiian Drosophila • Darwins Finches • Chichlids

  17. Pace of Evolution • Gradualism vs Punctuated Equilibrium

  18. Extinction Through Time • 5 Mass Extinctions have Occurred in the Past • Permian, 250 mya • Cretaceous, 65 mya • 6th extinction underway

  19. Future of Evolution • Thoughts????

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