What is usually the result of stabilizing selection in a population?

Stabilizing selection is a type of natural selection that favors intermediate phenotypes, leading to a reduction in variation within a population. This selection occurs when extreme traits are selected against, and individuals with average traits have a higher fitness. As a consequence, the frequency of these intermediate traits stabilizes over time, while the variations that exist at both ends of the spectrum diminish.

This trend results in decreased genetic diversity as alleles for extreme traits are selectively removed from the gene pool. The emphasis on the average phenotype means that the extremes, which might have previously contributed to the genetic variation of the population, become less common, leading to a more homogenous population regarding that trait.

While the other options touch on aspects of evolutionary dynamics, they do not encapsulate the primary consequence of stabilizing selection as accurately as the decrease in genetic diversity does. For example, while competition among average phenotypes may happen, it is not a direct result of stabilizing selection in the same way that reduced genetic diversity is. Similarly, the idea of increased fitness of extreme phenotypes contradicts the very nature of stabilizing selection, which works against those extremes. The focus of stabilizing selection is to maintain the status quo of traits rather than causing no change at all in