Question

Name and define the three types of natural selection.

Answer 1

1. Stabilising Selection: This type of selection favors the average phenotype and acts against extreme variations. It reduces variation in the population and maintains the status quo by eliminating individuals with extreme traits. It occurs when the environment remains stable and competition is not severe.
2. Directional Selection: In directional selection, one extreme phenotype is favored over others. This results in a shift of the population’s trait distribution toward that extreme over generations, often in response to changing environmental conditions. It leads to evolutionary change by increasing the frequency of new alleles that confer an advantage.
3. Disruptive Selection: Disruptive selection favors individuals at both extremes of a trait distribution and acts against intermediate phenotypes. This can result in a population splitting into two distinct groups, potentially leading to speciation if gene flow between the groups is prevented.