Final answer:
The four main mechanisms that contribute to evolution are mutation, gene flow, genetic drift, and natural selection, shaping the genetic diversity and allele frequencies within populations over time.
Step-by-step explanation:
The four main tasks that fall under maintenance and evolution in biological populations are: mutation, gene flow, genetic drift, and natural selection. These tasks describe the key mechanisms by which allele frequencies of a population can change over time, leading to evolution.
Mutation is the process by which new genetic variation is introduced into the gene pool. It is essential for evolution, providing the raw material for other mechanics to act upon. Gene flow is the transfer of alleles into or out of a population due to the movement of fertile individuals or gametes. Genetic drift describes how allele frequencies can fluctuate unpredictably from one generation to another, especially in small populations. Natural selection is the differential survival and reproduction of individuals due to differences in phenotype.
Genetic drift is most influential in small populations where random events can have a larger effect on the allele frequencies. An example of this is the founder effect, which occurs when a new colony is started by a few members of the original population, resulting in reduced genetic variation and a change in allele frequencies in the new population.