Final answer:
The Hardy-Weinberg theorem indicates that, unless evolutionary forces are at work, allele frequencies in a population remain constant across generations. It is foundational in understanding the genetic equilibrium of populations in the absence of factors such as natural selection, mutation, and gene flow.Hence, the correct answer is option 2.
Step-by-step explanation:
The Hardy-Weinberg theorem states that under certain conditions, allele and genotype frequencies will remain constant from one generation to the next within a population. This condition, known as Hardy-Weinberg equilibrium, assumes no mutation, no natural selection, no gene flow (migration), large population size, and random mating. Therefore, the correct statement is that in the absence of outside forces allele frequencies of a population will not change from one generation to another. It is an essential baseline in the field of population genetics that helps scientists compare actual population dynamics to a model of stability, allowing them to infer what evolutionary forces are influencing the population.
Importantly, the theorem does not suggest that dominant alleles are more common than recessive ones, that a locus can have only two alleles, or that it demonstrates speciation is occurring. It serves as a model to measure the balance or changes in allele frequencies, which reflect the genetic diversity and evolution within a population. It helps to identify factors such as natural selection, mutation, genetic drift, and migration that contribute to the evolution of populations over time.