Question

Define a natural selection, genetic drift.

Answer 1

Hint: Natural selection is an evolutionary process in which differential survival and selective changes in trait occur over time. In genetic drift, the allele frequencies change all of a sudden, due to random sampling effect.

Complete answer: Natural selection and genetic drift both are concepts that deal with evolutionary processes. These describe how evolution can occur through the influence of different forces.
Evolution refers to the change in heritable traits of populations over the subsequent generations.

1. Natural selection: It refers to the gradual adaption process by an organism according to its surrounding environment. It occurs by selective changes in a species’ genotype or its genetic constitution. Natural selection refers to the differential survival under various natural forces.
2. Genetic drift: It refers to the change in the frequency of an existing allele (gene variant) in a population. It happens due to the random sampling of organisms.
Genetic drift is also called the Sewall Wright effect or allelic drift.

Note: Natural selection is a key mechanism operating in evolution.
It was popularized by Charles Darwin. The genetic drift concept was put forward by Sewall Wright who is also a founder of the subject ‘Population genetics’.