Final answer:
Natural selection is a process that drives evolution by favoring traits that increase survival and reproduction. Other factors like genetic drift, gene flow, mutation, nonrandom mating, and environmental factors can also influence allele frequencies.
Step-by-step explanation:
Natural selection is a process that drives evolution by favoring individuals with traits that increase their chances of survival and reproduction. This leads to changes in allele frequencies in a population over time. For example, consider a population of birds with different beak sizes. If larger beaks allow birds to access more food, they will have a higher chance of survival and reproduction, leading to an increase in the frequency of genes associated with larger beaks in the population.
In addition to natural selection, other factors can also influence allele frequencies. Genetic drift refers to random changes in allele frequencies due to fluctuation in population size. The bottleneck effect occurs when there is a drastic reduction in the population size, leading to a loss of genetic diversity. The founder effect happens when a small group of individuals establishes a new population, resulting in the allele frequencies of the new population being different from the original population. Gene flow occurs when individuals migrate and introduce new alleles into a population through mating. Mutations introduce new genetic variation into a population, which can affect allele frequencies. Nonrandom mating refers to selective mating based on certain traits, which can lead to changes in allele frequencies. Lastly, environmental factors can influence selection pressures and impact allele frequencies.