| A | B |
|---|
| stabilizing selection | individuals in the middle of a phenotypic range have a higher fitness than other individuals in the population |
| directional selection | individuals at one extreme end of a phenotypic range have a higher fitness than other individuals in the population |
| genetic drift | random change in the allele frequency of a population |
| bottleneck effect | a change in the allele frequency of a population due to a dramatic reduction in the size of a population |
| Hardy Weinberg principle | states that allele frequencies in a population remain constant unless one or more factors cause it to change |
| sexual selection | when individuals select mates based on heritable traits |
| species | a population whose members can interbreed to produce fertile offspring |
| speciation | the formation of new species |
| reproductive isolation | when two populations can no longer interbreed |
| behavioral isolation | differences in courtship rituals or other behaviors that prevent two populations from interbreeding |
| geographic isolation | physical barriers separate two populations and prevent them from interbreeding |
| temporal isolation | when populations reproduce at different times, preventing them from interbreeding |
| founder effect | a change in the allele frequency of a population due to the migration of a small subgroup of a population |
| genetic equilibrium | when allele frequencies of a population do not change |
| disruptive selection | individuals at both extremes of a phenotypic range have a higher fitness than individuals in middle range of the population |
