What is the outcome of directional selection?

Directional selection is a type of natural selection that favors one extreme phenotype over others, leading to a shift in the population's allele frequencies. This occurs when environmental changes or specific advantages favor individuals with traits at one end of the phenotypic spectrum. For example, if a particular trait confers a significant survival advantage, individuals exhibiting that trait will reproduce more successfully, causing the frequency of alleles associated with that trait to increase in the population over time.

In directional selection, the focus on one extreme phenotype means that the average trait value in the population will shift in that direction. This leads to a change in the adaptive characteristics of the population, as those individuals better suited to the prevailing conditions are selected for.