Answer:
directional selection
Step-by-step explanation:
Directional selection is a type of natural selection where individuals exhibiting an extreme phenotype for a given trait are favored over the mean or other extreme phenotype. This type of selection can lead to drastic and fast changes in allele frequencies between generations in a population, being particularly important in speciation processes. Directional selection is common under environmental changing conditions (e.g., weather, climate, food availability, etc) or when individuals migrate to other regions in order to adapt to new environmental pressures.