Answer:
Genetic drift refers to random fluctuations in the frequencies of alleles (different forms of a gene) in a population, due to chance events. These fluctuations can cause rapid changes in genetic frequencies, particularly in small populations.
In a small population, chance events like random deaths or births can have a disproportionate impact on the frequency of particular alleles. For example, if a few individuals with a rare allele die or fail to reproduce, that allele's frequency in the population will decrease. Conversely, if a few individuals with a rare allele happen to have many offspring, that allele's frequency will increase.
Over time, these chance events can cause certain alleles to become more or less common in a population, even if those alleles don't provide any particular advantage or disadvantage to the organisms carrying them. This can result in rapid, random changes in genetic frequencies that are not driven by natural selection or any other factor.
In larger populations, the effects of genetic drift are typically smaller and more gradual, since chance events are more likely to be balanced out by other chance events. However, in very small populations or isolated populations, genetic drift can be a major force driving evolutionary change.