What does genetic drift refer to in the context of human evolution?

Genetic drift refers to the random change in allele frequencies within a population over time due to chance events. This mechanism is particularly significant in small populations where random events can lead to large fluctuations in allele frequencies, thus affecting the genetic diversity of the population. As certain alleles may increase or decrease purely by chance rather than by selection pressure, genetic drift can lead to differences between populations and contribute to the evolutionary process.

In the context of human evolution, genetic drift can explain why certain traits may become more or less common in isolated populations. Unlike selection, which favors traits that provide an advantage for survival or reproduction, genetic drift is not directional; it is entirely influenced by random changes, which can lead to unexpected outcomes in genetic traits. This randomness can have profound effects on the course of evolution, especially in small groups where the effects of drift can be magnified. Understanding genetic drift is crucial in proving how human populations can diverge genetically over time.