WTMA Biology Unit 5, Set 3

genetic equilibrium

a condition in which the frequency of alleles is the same in a population from generation to generation

genetic drift

a change in allele frequency due to chance, like founder effect or population bottleneck

gene flow

a change in allele frequency due to migration in or out of the population

nonrandom mating

a change in allele frequency due to factors like proximity affecting mate choice

mutation

a change in allele frequency due to changes in the DNA of organisms in the population

directional selection

natural selection that favors one extreme of a trait distribution

stabilizing selection

natural selection that favors the mean (middle) of a trait distribution

disruptive selection

natural selection that favors both extremes of a trait distribution

allopatric speciation

speciation that occurs due to a physical barrier between populations

sympatric speciation

speciation that occurs with two populations living side by side without a physical barrier

pre-zygotic isolation

reproductive isolation that prevents fertilization from happening

post-zygotic isolation

reproductive isolation that arises from inviable or infertile hybrid offspring