The term "genetic drift" in evolution refers to random changes in the allele frequencies of a population over time. This process occurs due to chance events, especially in small populations, leading to certain alleles becoming more or less common regardless of their adaptive value. For instance, if a few individuals contribute disproportionately to the next generation, their genes may dominate purely by chance. Genetic drift contrasts with natural selection, where environmental pressures favor certain traits. It can lead to reduced genetic variation and, in extreme cases, can result in the extinction of entire populations.