What phenomenon occurs when a few individuals become isolated from a larger population?

The founder effect occurs when a small number of individuals from a larger population establish a new population in a different location. This situation often leads to a limited gene pool, meaning that the genetic diversity of the new population is restricted to the alleles present in the founders. Because of this reduced genetic variation, certain traits may become more common in the new population compared to the original population. This phenomenon can have significant implications for the evolution and survival of the new population, as it may lead to increased susceptibility to environmental changes or diseases due to the lack of genetic diversity.

In contrast, gene flow refers to the transfer of genetic material between populations through migration, which does not involve isolation. Genetic drift is a random change in allele frequencies that occurs in a population, especially in small populations, but does not specifically relate to the reducing effect of a small founding group. Mutation, on the other hand, introduces new genetic variations into a population but does not directly involve the isolation of individuals from a larger population. Thus, the founder effect specifically addresses the consequences of isolation by a small group and its impact on genetic diversity.