Final answer:
Genetic drift is a process in which random events cause changes in allele frequencies within a population, especially in small populations, leading to reduced genetic variation and increased genetic similarity among individuals.
Step-by-step explanation:
Genetic drift is a phenomenon where allele frequencies in a population change due to random events rather than natural selection. This process is particularly influential in small populations where by chance alone, some alleles may be lost completely, thus reducing genetic variation.
An example of genetic drift is the bottleneck effect, which can occur when a disaster, such as a hurricane or wildfire, randomly eliminates a large portion of a population regardless of their genotypes.
This can significantly alter the genetic structure of the remaining population. In contrast, the founder effect is another example where a new population is established by a few individuals from a larger population, potentially carrying only a small fraction of the genetic diversity.
Small populations are more vulnerable to genetic drift as they have less genetic variation to begin with; so when alleles are lost due to chance events, it has a greater impact on the population's genetic diversity.
For instance, if one individual in a population of ten dies before reproducing, 10% of the genetic variation could be lost. This contrasts with that same single death in a population of 100, where only 1% of variation would be potentially lost.
Chance events, like the death of the only white rabbits in a storm, can remove alleles from a population's gene pool.
In such cases, genetic drift can result in a population with reduced genetic variation and increased similarity among its individuals, making the population less able to adapt to new environmental challenges.
The complete question is: By causing alleles to be lost from a population genetic drift reduces the genetic variation of the population making individuals within the population more similar genetically to one another. Elaborate!