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.   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.

Objectives: SWBAT…   Explain that new mutations are constantly being generated in a gene pool, and this can cause evolution.   Understand the decrease in genetic diversity in a population caused by genetic drift.

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

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

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

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)

Genetic Drift Bottleneck Effect Polydactyl (Amish)

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?  Explain standard 8c in your own words.