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19.2 Patterns of Evolution

19.2 Patterns of Evolution. H1N1 Swine FLU VIRUS. Macroevolutionary patterns - large scale evolutionary changes that occur over millions of years. Extinctions. Mass extinction - many species become extinct over a short period of time

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19.2 Patterns of Evolution

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  1. 19.2 Patterns of Evolution

  2. H1N1 Swine FLU VIRUS

  3. Macroevolutionary patterns - large scale evolutionary changes that occur over millions of years

  4. Extinctions • Mass extinction - many species become extinct over a short period of time • Causes: huge meteors, supervolcanoes, climate change?!?

  5. Background extinction - single species becomes extinct by lack of adaptation

  6. Mass extinctions reduce genetic pool (biodiversity), then speciation occurs to fill empty niches

  7. Two views of evolution • Gradualism - slow and steady genetic change • Punctuated Equilibrium - steady states mixed with quick changes in genetics

  8. GRADUALISM PUNCTUATED EQUILIBRIUM

  9. Macroevolutionary Patterns 1) Adaptive Radiation - one species evolving into many similar species

  10. 2) Convergent evolution - organisms evolve in different but similar environments and end up similar due to environmental pressure or selection

  11. Coevolution - two species evolve in response to changes in each other • Ex) flowering plants and pollinators

  12. Some insects evolve resistances to plant poisons

  13. Remember - changes in environment drive evolutionary change!

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