Question

Genetic drift operates in:
(a) Non reproduction population
(b) Slow reproduction population
(c) Small isolated population
(d) Large isolated population.

Answer 1

Genetic drift is the elimination or addition of genes of certain characteristics when some animals in a population migrate or die or immigrate. It changes the gene frequency of the remaining population. Genetic drift is one of the main reasons for genetic variation.

Complete answer:
- Genetic drift operates in a small population because a small change in genes can have a high impact.
- By genetic drift often the phenotype of this small population quickly becomes different from the parent population.
- According to the Hardy Weinberg principle, there are many factors that contribute to Hardy Weinberg equilibrium. Any change in it results in evolution.
- Gene flow, genetic drift, mutation, genetic recombination, and natural selection affects this equilibrium.
- During migration, gene frequency changes in the population as new alleles get lost from the older population.
- When gene migration happens multiple times it is called gene flow. If it occurs by chance, it is called genetic drift.
- Sometimes genetic drift becomes so prominent that a newly formed population may become a different species.
- The population from which the new one was formed became founders and this is called the founder effect.

Additional information:
- Neo-Darwinism is a modified form of Darwinism.
- The salient features of neo- Darwinism are rapid multiplication, limited food space, the struggle for existence, genetic variations,
- Change in the frequency of genes in a gene pool is called drift.
So the correct answer is genetic drift operates in a small isolated population.

Note: Death of several members of a population due to natural calamities leads to genetic drift. Mating can restore the original size of the population. It may lack some genes. This loss of a section of a population by death and later new species is formed is called the Bottleneck effect.