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What causes evolution?

What causes evolution?. Is this evolution? If so, what caused it?. Generally Speaking a mechanism of evolution is…. Any event that alters the frequency of traits in a population. 1. Mutations. Raw material for evolution. The effect of a mutation on an organism is dependent on environment.

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What causes evolution?

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  1. What causes evolution?

  2. Is this evolution? If so, what caused it?

  3. Generally Speaking a mechanism of evolution is… • Any event that alters the frequency of traits in a population

  4. 1. Mutations • Raw material for evolution

  5. The effect of a mutation on an organism is dependent on environment

  6. 2. Genetic Drift • Changes in trait frequency due to chance • 2 types: • Founders Effect • Bottleneck Effect

  7. What are some chance events that can occur in a population?

  8. Founders Effect Small group of individuals branch from original population and found new population

  9. Example of Founders Effect

  10. Bottleneck Effect

  11. Example of Bottleneck Effect

  12. 3. Gene Flow • Movement of traits between populations • Immigration (in) • Emigration (out)

  13. 4. Non-random mating Individuals pair up, not by chance, but according to their traits

  14. 5. Natural Selection

  15. Types of Natural Selection • Stabilizing Selection • Frequency of “average” trait increases over time

  16. Types of Natural Selection • Directional Selection • Frequency of 1 “extreme” trait increases over time

  17. Types of Natural Selection • Disruptive Selection • Frequency of both “extreme” traits increases over time

  18. If Darwin’s theory is correct, how are certain deleterious alleles maintained in populations?Heterozygote Advantage

  19. Sickle Cell and Malaria

  20. 7. Artificial Selection • Humans adjust environment to guide evolution • Synonym = Selective breeding

  21. Over time these mechanisms will lead to different patterns of evolution… 1. Convergent Evolution= 2 species develop traits with similar form and function

  22. Over time these mechanisms will lead to different patterns of evolution… 2. Divergent Evolution= accumulation of differences in a species over time that can lead to creation of new species

  23. Over time these mechanisms will lead to different patterns of evolution… 2. Coevolution= changes in one population due to changes in a related population

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