Answer:
Genetic drift
Step-by-step explanation:
Genetic drift refers to the random fluctuations in allele frequencies that occur in small populations due to chance events. These chance events can lead to the loss or fixation of specific alleles in a population over time. In small populations, genetic drift can have a significant impact on the genetic makeup of the population. Still, the changes are generally smaller in magnitude compared to other mechanisms of evolution.
In contrast, natural selection, gene flow, and mutation can lead to more significant and directional changes in allele frequencies over time. Natural selection favors specific alleles that provide a reproductive advantage, leading to their increase in the population. Gene flow introduces new genetic variation into a population through the movement of individuals between populations. Mutation introduces new alleles into a population through genetic changes. These mechanisms can result in larger and more noticeable evolutionary changes than genetic drift.