Final answer:
The processes that result in changes in allele frequencies in a population's gene pool include natural selection, genetic drift, gene flow, mutation, nonrandom mating, and environmental variances.
Step-by-step explanation:
Changes in allele frequencies in a population's gene pool can result from several processes, including natural selection, genetic drift, gene flow, mutation, nonrandom mating, and environmental variances.
Natural selection occurs when certain alleles confer a selective advantage, allowing individuals with those alleles to have more offspring that survive and reproduce. This leads to an increase in the frequency of the advantageous alleles and a decrease in the frequency of other alleles.
Genetic drift, on the other hand, is a random process that can cause allele frequencies to change due to chance. It is most prominent in small populations where chance events can have a greater impact. Genetic drift can lead to the loss of alleles or the fixation of certain alleles in a population.