How does genetic drift typically affect small populations?

Genetic drift is a mechanism of evolution that occurs due to random sampling effects in small populations. In these populations, allele frequencies can fluctuate unpredictably over generations because random events can have a disproportionate impact on the population's genetic makeup. This randomness means that certain alleles may become more or less common not because of their adaptive value but simply by chance, leading to changes in allele frequencies over time.

In small populations, these random changes can be particularly pronounced since the sample size is limited. A single individual's reproductive success (or lack thereof) can significantly influence the genetic structure of the next generation. As a result, genetic drift can lead to the loss of genetic variation, possibly resulting in a decrease in genetic diversity within the population over time.

While genetic drift can have diverse implications for the population's adaptability and response to environmental changes, its defining characteristic is this randomness in allele frequency changes, confirming that the most accurate understanding of its effect on small populations is the random nature of the changes in allele frequencies.