Which of the following is a possible explanation for why a population may not be in Hardy-Weinberg equilibrium?

• A. The population is infinitely large.
• B. Non-random mating occurs within the population.
• C. No migration occurs between populations.
• D. There is no mutation affecting the gene pool.

Answer: (B)

Verified step by step guidance

1. Step 1: Begin by understanding the Hardy-Weinberg equilibrium. It is a principle stating that allele and genotype frequencies in a population will remain constant from generation to generation in the absence of evolutionary influences.
2. Step 2: Review the conditions required for Hardy-Weinberg equilibrium. These include: (1) infinitely large population size, (2) random mating, (3) no mutation, (4) no migration, and (5) no natural selection.
3. Step 3: Analyze the given options to identify which condition is violated. The option 'Non-random mating occurs within the population' suggests that individuals are choosing mates based on specific traits, which violates the random mating condition.
4. Step 4: Understand why non-random mating disrupts Hardy-Weinberg equilibrium. Non-random mating can lead to changes in genotype frequencies, as certain alleles may become more common due to preferential mating patterns.
5. Step 5: Conclude that the correct explanation for why the population may not be in Hardy-Weinberg equilibrium is the occurrence of non-random mating, as it directly violates one of the key conditions of the principle.