Microevolution Mechanisms and Selection patterns

natural selection

A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits.

genetic drift

A change in the allele frequency of a population as a result of chance events rather than natural selection.

bottleneck effect

A change in allele frequency following a dramatic reduction in the size of a population

founder effect

change in allele frequencies as a result of the migration of a small subgroup of a population

Mutation

A change in a gene or chromosome.

gene flow

movement of alleles from one population to another

sexual selection

A form of natural selection in which individuals with certain inherited characteristics are more likely than other individuals to obtain mates.

directional selection

Form of natural selection in which the entire curve moves; occurs when individuals at one end of a distribution curve have higher fitness than individuals in the middle or at the other end of the curve

disruptive selection

form of natural selection in which a single curve splits into two; occurs when individuals at the upper and lower ends of a distribution curve have higher fitness than individuals near the middle

stabilizing selection

Natural selection that favors intermediate variants by acting against extreme phenotypes