Final answer:
Female cardinals preferring males with bright red plumage is a form of natural selection, causing the red allele frequencies to increase and disrupting Hardy-Weinberg equilibrium. The effect on the population would be a higher frequency of red alleles than predicted by the equilibrium. So, the correct option is (2) The frequency of red alleles would be greater than those predicted by Hardy-Weinberg equilibrium.
Step-by-step explanation:
Female cardinals selecting male mates based on their bright red color is an example of sexual selection, a form of natural selection. Because female cardinals prefer males with bright red plumage, these males are likely to have more offspring, thereby increasing the frequency of the red alleles in the population. Therefore, the effect on a cardinal population that was initially in Hardy-Weinberg equilibrium would be to disrupt this equilibrium. The expected outcome would be (2) The frequency of red alleles would be greater than those predicted by Hardy-Weinberg equilibrium. The Hardy-Weinberg equilibrium principle states that allele frequencies in a population will remain constant in the absence of factors such as natural selection, mutation, genetic drift, migration, and nonrandom mating. Since the female cardinals' mate choice is leading to nonrandom mating and since bright red coloration provides a mating advantage, natural selection is occurring, and the population is evolving.