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Chapter 24 The Origin of Species

Chapter 24 The Origin of Species. Chapter 24 The Origin of Species. Microevolution (you will remember from chapter 23) is …. Chapter 24 The Origin of Species. Microevolution (you will remember from chapter 23) is the generation-to-generation change in allele frequencies within a species.

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Chapter 24 The Origin of Species

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  1. Chapter 24The Origin of Species

  2. Chapter 24The Origin of Species Microevolution (you will remember from chapter 23) is …

  3. Chapter 24The Origin of Species Microevolution (you will remember from chapter 23) is the generation-to-generation change in allele frequencies within a species

  4. Chapter 24The Origin of Species Microevolution (you will remember from chapter 23) is the generation-to-generation change in allele frequencies within a species. Macroevolution (on the other hand) is the origin of new species.

  5. Chapter 24The Origin of Species Macroevolution happens two ways:

  6. Chapter 24The Origin of Species Macroevolution happens two ways: Anagenesis – linear evolution Cladagenesis – branching evolution

  7. Chapter 24The Origin of Species Macroevolution happens two ways: Anagenesis – linear evolution Cladagenesis – branching evolution

  8. Chapter 24The Origin of Species Macroevolution happens two ways: Anagenesis – linear evolution Cladagenesis – branching evolution

  9. Chapter 24The Origin of Species What is a species?

  10. Chapter 24The Origin of Species What is a species? Reproductive isolation based on prezygotic and postzygotic barriers.

  11. Chapter 24The Origin of Species Prezygotic barriers: • Habitats • Mating behaviors • Mating seasons • Mechanical incompatibility • Gamete incompatibility.

  12. Chapter 24The Origin of Species Postzygotic barriers: • Embryo is inviable • Offspring do not survive to adulthood • Offspring are infertile.

  13. Chapter 24The Origin of Species Species concept does not apply to:

  14. Chapter 24The Origin of Species Species concept does not apply to: • Fossils • Asexual reproduction.

  15. Chapter 24The Origin of Species Other proposed definitions of species:

  16. Chapter 24The Origin of Species Other proposed definitions of species: • Ecological • Morphological • Pluralistic • Genealogical.

  17. Chapter 24The Origin of Species Speciation Allopatric – Sympatric –

  18. Chapter 24The Origin of Species Speciation Allopatric – Geographic barriers divide a population Sympatric –

  19. Chapter 24The Origin of Species Speciation Allopatric – Geographic barriers divide a population Sympatric – New species develop in the midst of parent species.

  20. Chapter 24The Origin of Species Causes of sympatric speciation:

  21. Chapter 24The Origin of Species Causes of sympatric speciation: • Polyploidy (mostly in plants) • Host switching (in parasites) • Nonrandom mating (in polymorphic populations).

  22. Chapter 24The Origin of Species Punctuated equilibrium Species change quickly as they bud off from parent species, then change relatively little for the rest of their existence.

  23. Chapter 24The Origin of Species Evolutionary Novelties

  24. Chapter 24The Origin of Species Evolutionary Novelties • Modifications of older structures

  25. Chapter 24The Origin of Species Evolutionary Novelties • Modifications of older structures • Functions may change or may stay the same.

  26. Chapter 24The Origin of Species “Evo-Devo”

  27. Chapter 24The Origin of Species “Evo-Devo” Genes that control development play a major role in evolution.

  28. Chapter 24The Origin of Species “Evo-Devo”

  29. Chapter 24The Origin of Species “Evo-Devo”

  30. Chapter 24The Origin of Species A trend is not a goal. Evolution is not goal oriented.

  31. Chapter 24The Origin of Species A trend is not a goal. Evolution is not goal oriented. .

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