Honors HSBio 13 - Speciation and Population Genetics

gene pool

the collections of alleles within a population

allele frequency

how often an allele is present in a population

stabilizing selection

natural selection that favors the average type of individual

disruptive selection

natural selection that favors the two extremes of a population

directional selection

natural selection that favors individuals in one direction or another in a population

genetic equilibrium

when the allele frequency does not change between generations

speciation

process by which a new species formed

isolation

when two groups of organisms are prevented from reproducing for a variety of reasons. Examples include reproductive, temporal, geographic, and behavioral isolation.

extinction

dying out or extermination of an entire species

nonrandom mating

mate selection is influenced by phenotypic differences based on underlying genotypic differences

gene flow

the movement of genes into or out of a population

bottleneck Effect

when an event of nature or human impact suddenly eliminates many organisms in a population and narrows the gene pool

genetic drift

variation in the relative frequency of different genotypes in a small population, owing to the chance disappearance of particular genes as individuals die or do not reproduce.

founder effect

change in allele frequencies because of migration of a population into or out of a population

convergent evolution

when two groups of organisms evolve similar characteristics due to livivng in a similar environment.

divergent evolution

when two groups of organisms evolve to become more different over time

coevolution

when two species evolve in response to changes in each other over time "moth and flower"