Go Green and Conquer: 2025 Ecology Science Olympiad Practice Challenge!

Genetic drift is a mechanism of evolution that refers to random changes in allele frequencies within a population, particularly in small populations. One of the key consequences of genetic drift is the reduction of genetic variation over time. As alleles fluctuate randomly, some may become fixed (reach 100% frequency) or lost (reach 0% frequency), leading to a decrease in the overall genetic diversity of the population. This reduction in genetic variation can make a population more vulnerable to environmental changes and reduce its ability to adapt to new selective pressures.

In contrast, larger populations tend to buffer against the effects of genetic drift because the random changes in allele frequencies tend to average out. Therefore, the correct response highlights the impact of genetic drift specifically in small populations, where its effects are more pronounced and can lead to a significant loss of genetic variation.