Natural selection leads to changes in allele frequencies based on what criteria?

Natural selection is a fundamental mechanism of evolution that drives changes in allele frequencies within a population over time. The correct answer focuses on the impact of alleles on survival and reproduction. This means that certain alleles confer advantages that make individuals more fit for their environment, leading to higher rates of survival and reproduction for those individuals compared to others.

When an allele provides a beneficial trait—such as better camouflage, disease resistance, or increased fertility—individuals carrying that allele are more likely to survive and reproduce. Over generations, this selective pressure results in an increase in the frequency of those advantageous alleles within the population. This process illustrates how traits that enhance survival and reproduction become more common, shaping the genetic profile of the population.

In contrast, while genetic drift refers to random fluctuations in allele frequencies due to chance events, it does not involve selection based on traits. Random mating does not directly influence which alleles become more prevalent; rather, it’s the preferences related to advantageous traits that affect survival rates. Environmental changes can impact survival, but natural selection specifically involves how these changes interact with the traits conferred by alleles to influence reproductive success.