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The Genetics of Evolution

The Genetics of Evolution. What is the relationship between the genes of a population and evolution?. Standards:. BI7. a. Students know why natural selection acts on the phenotype rather than the genotype of an organism.

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The Genetics of Evolution

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  1. The Genetics of Evolution What is the relationship between the genes of a population and evolution?

  2. Standards: • BI7. a. Students know why natural selection acts on the phenotype rather than the genotype • of an organism. • BI7. c. Students know new mutations are constantly being generated in a gene pool. • BI8. c. Students know the effects of genetic drift on the diversity of organisms in a population.

  3. Objectives: SWBAT… • Explain thatnew mutations are constantly being generated in a gene pool, and this can cause evolution. • Understandthe decrease in genetic diversity in a population caused by genetic drift.

  4. Where does the genetic variation come from for evolution? • Gene pool-combined alleles for all the individuals in a population • Genetic variation is stored in the gene pool • Alleles-different forms of trait (eye color) • Allele frequency-measure of how common an allele is in a population

  5. What are the five factors that can cause evolution? • Genetic drift-allele frequencies can change due to chance alone • Gene flow-the movement of alleles from one population to another, changes allele frequencies in each pop. • Mutation-can form new alleles, creates genetic variation needed for evolution • Sexual selection-certain traits may improve mating success • Natural selection-certain traits can help survival, these traits increase in frequency

  6. What is gene flow? • Gene flow-movement of alleles from one population to another • Occurs when individuals of species move between populations • Increases genetic variation

  7. What processes allow genetic drift to take place? • Genetic drift-changes in allele frequency due to chance, decreases genetic diversity • Bottleneck effect-GD that occurs after an event greatly reduces the size of the population. (overhunting) • Founder effect-GD that occurs after a small number of individuals colonize a new area. (islands)

  8. Genetic Drift Bottleneck Effect Polydactyl (Amish)

  9. Summary Questions • What is the gene pool of a population? • Name two genetic factors that can cause evolution. • Does genetic drift decrease or increase genetic diversity? • What is the relationship between the genes of a population and evolution?

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