Final answer:
Factors that affect a population's genetic equilibrium, other than natural selection, include genetic drift, gene flow, mutation, nonrandom mating, and environmental variances. These can all cause changes in allele frequencies and thereby influence the evolution of the population.
Step-by-step explanation:
Apart from natural selection, other factors that can upset a population's genetic equilibrium include genetic drift, gene flow, mutation, nonrandom mating, and environmental variances. These are essential evolutionary forces that shape the genetic makeup of populations.
Genetic Drift
Genetic drift occurs by chance and can dramatically change allele frequencies in a population. Events like natural disasters can lead to a bottleneck effect, where a significant portion of a gene pool is wiped out, and the genetic structure of the survivors becomes representative of the entire population. The founder effect is when a new colony is started by a few members of the original population, leading to a reduced genetic variation and a potentially different allele frequency from the original population.
Gene Flow
Gene flow involves the transfer of alleles or genes from one population to another, often due to the migration of individuals or gametes, thereby altering allele frequencies.
Mutation
Mutation introduces new genetic variation into a population. Although mutations are random, they provide the raw material for evolutionary change and can be neutral, beneficial, or deleterious.
Nonrandom Mating
Preferences for mates or mating patterns that are not random can affect which genes are passed on to the next generation, influencing genetic equilibrium.
Environmental Variances
Different environments can lead to phenotypic changes that are not necessarily genetic but can affect reproductive success.