Which type of selection occurs when a population moves into a new environment?

When a population moves into a new environment, directional selection often occurs. This form of natural selection favors one extreme phenotype over others, leading to a shift in the population's trait distribution. As individuals better adapted to the new environmental conditions are more likely to survive and reproduce, their advantageous traits become more common over generations.

In the context of a population adapting to a different environment, those individuals with traits that provide a survival advantage in the new setting will thrive. For instance, if a population of animals that is typically lighter in color moves into a darker habitat, darker individuals might be favored because they blend in better with their surroundings, reducing predation risk. Over time, the gene pool of the population shifts toward these advantageous traits due to the influence of directional selection.

Stabilizing selection, on the other hand, typically occurs in stable environments and favors intermediate phenotypes, rather than those at one extreme. Disruptive selection involves favoring both extremes of a trait and is less commonly linked with initial colonization of new environments. Gene flow refers to the transfer of genetic material between populations and is not a type of selection in itself. Thus, directional selection is the appropriate choice when considering adaptations in response to new environments.