Microevolution

microevolution

evolution on the smallest scale; change in allele frquency in a population over gen

sources of genetic variation

mutations and meiosis

population genetics

study of how populations change genetically over time

population

group of individuals of same species that live in the same area and interbreed, producing fertile offspring

gene pool

all alleles at all loci in all members of a population

fixed allele

all members of a population are homozygous for same allele (can not change)

conditions for hardy-weinberg equilibrium

1. no mutations

2. random mating (no sexual selection)

3. no natural selection

4. large population size (no genetic drift)

5. no gene flow (no emigration or immigration)

major mechanism of evolution

1. natural selection

2. genetic drift

3. gene flow

bottleneck effect

severe drop in population size; certain alleles can be over/under-represented

founder effect

few individuals become isolated from larger population →certain alleles can be over/under-represented

gene flow

population gains/loses alleles due immigration and emigration

relative fitness

contribution an individual makes to the gene pool of the next generation relative to the contribution of others

diploidy

inherit 2 alleles; heterozygote have better survival

intrasexual selection

competition within same sex for mating

intersexual selection

selection involving individuals of one sex choosing mates based on traits.

sexual dimorphism

difference between two sexes of a species