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Understanding Evolution: Species & Selection

Explore evidence for evolution, including Darwin's finches, industrial melanism, fossil records, anatomical and anatomical evidence, critiquing Darwin's theories, speciation, and the pace of evolution. Discover how natural selection, reproduction isolation, adaptive radiation, and extinction shape species.

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Understanding Evolution: Species & Selection

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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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