What does directional stabilization refer to in evolutionary terms?

Directional stabilization in evolutionary terms refers to the process where natural selection favors individuals at one extreme of a trait distribution over others. This leads to a shift in the population's characteristics over time, as the traits that enhance the survival or reproductive success of individuals become more prevalent. Essentially, it promotes a change in the population toward a particular direction or extreme trait that is advantageous in a given environment.

For example, if a particular type of bird has a beak shape that allows it to access food more efficiently than others, directional selection would favor birds with that beak shape, leading to an increased frequency of that trait in subsequent generations. This contrasts with stabilizing selection, which favors average traits, and disruptive selection, which favors extreme traits at both ends of the spectrum.