Final answer:
In a population at Hardy-Weinberg equilibrium, no evolutionary changes would occur. This equilibrium is maintained if five specific conditions are met, including no mutations, no gene flow, large population size, random mating, and no natural selection.
Step-by-step explanation:
If a population was in Hardy-Weinberg equilibrium, then no evolutionary changes would occur in that population. The Hardy-Weinberg model outlines five conditions required for this equilibrium: (1) No mutations that affect the allele frequency, (2) No gene flow or migration into or out of the population, (3) A sufficiently large population size to prevent genetic drift, (4) Random mating where individuals pair by chance, not by genotype or phenotype, and (5) No natural selection where all individuals have an equal chance of survival and reproduction regardless of their genotype.
Departure from these conditions would lead to changes in allele frequencies indicating that the population is evolving. For example, if individuals tend to mate with those of a similar genotype (assortative mating), then the genotype frequencies would change, although allele frequencies would remain the same unless the alleles affect reproductive success. In contrast, factors such as genetic drift or migration (gene flow) can directly change allele frequencies. However, in reality, no natural population is entirely free from evolutionary forces, and therefore, the Hardy-Weinberg equilibrium serves as a theoretical benchmark rather than a common natural occurrence.