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UNIT 6 - Evolution

UNIT 6 - Evolution. 9.10.2 SWBAT identify other evolutionary mechanisms of natural selections and compare them with natural selection. What is this bid doing and why?. http:// www.youtube.com / watch?v =8tO80BvZapA. IBE - JTPS.

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UNIT 6 - Evolution

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  1. UNIT 6 - Evolution 9.10.2 SWBAT identify other evolutionary mechanisms of natural selections and compare them with natural selection

  2. What is this bid doing and why? • http://www.youtube.com/watch?v=8tO80BvZapA

  3. IBE - JTPS • Have you ever wondered why many male birds, such as cardinals, are brightly colored while females of the same species are dull brown?

  4. J-TPS (Justify –Think Pair Share) THINK PAIR SHARE

  5. Natural selection is not the only mechanism through which populations evolve

  6. Mechanisms for evolution • Gene flow • Genetic drift • Sexual Selection • Mutation • Speciation • Natural selection

  7. Mechanisms for evolution • Gene flow • Genetic drift • Sexual Selection • Mutation • Speciation • Natural selection

  8. Gene flow is the movement of alleles between populations • Gene flow increases genetic variation What are alleles?

  9. Mechanisms for evolution • Gene flow • Genetic drift (founder effect and bottleneck effect) • Sexual Selection • Mutation • Speciation • Natural selection

  10. Genetic Drift The process of allele frequency change (evolution) in a population due to chance or random events

  11. Genetic drift can be expressed as a “bottleneck effect” • It is usually as a result of a catastrophe or unforeseen event

  12. Genetic drift can also be caused by the “Founder Effect.” • It occurs after a small number of individuals colonize a new area.

  13. Mechanisms for evolution • Gene flow • Genetic drift • Sexual Selection • Mutation • Speciation • Natural selection

  14. Sexual selection occurs when certain traits increase mating success • Intrasexual - involves competition between males

  15. Sexual selection • Intersexual - involves traits that attract the opposite sex

  16. White board A change in the allele frequency due to migration (individual coming in or out) in a population is called? 1. genetic drift 2. sexual selection 3. bottleneck effect 4. gene flow

  17. White board The five factors that can lead to evolution are gene flow, genetic drift, mutation, natural selection, and 1. sexual selection 2. controlled mating 3. emigration 4. immigration

  18. White board ________ changes allele frequencies due to chance alone 1. Natural selection 2. Gene flow 3. Genetic drift 4. Mutations

  19. Critical thinking • How does gene flow affect neighboring populations?

  20. Critical thinking • How does gene flow affect neighboring populations? • Gene flow decreases genetic diversity between neighboring populations.

  21. Critical thinking • Would a population of 10 individuals or 100 individuals be more vulnerable to genetic drift? Why?

  22. Critical thinking • Would a population of 10 individuals or 100 individuals be more vulnerable to genetic drift? Why? • A smaller population is more vulnerable to genetic drift because it has a smaller gene pool and is therefore more likely to be affected by chance events.

  23. IBE - JTPS • Have you ever wondered why many male birds, such as cardinals, are brightly colored while females of the same species are dull brown? Such bright coloring may not make sense in terms of natural selection, since the male birds are more likely to be seen by predators. However, natural selection is not the whole story.

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