Question

Genetic drift operates only in
A) Larger population
B) Mendelian population
C) Island population
D) Smaller population

Answer 1

Random change in the frequency of alleles in a population is the genetic drift. It is due to chance events causing unequal participation of individuals in producing succeeding generations.

Complete answer:
Let's discuss and find out the correct answer.

Option A: For a large and growing population Water scarcity may be an outcome. A large population means more water. It is not only for domestic use, but also it is used to produce more food. Hence, water resources are being over-exploited to expand irrigated areas and dry-season agriculture to facilitate higher food-grain production. Hence option A is incorrect.
Option B: Mendelian population is a group of interbreeding individuals. The gene pool is known by the sum total of allelic gene content of a particular group is known as their. Hence option B is incorrect.
Option C: Island population is not in this category. Hence option C is incorrect.
Option D: The evolution was caused due to the random change in the allele frequencies of a population over generations. It is mainly caused in small isolated populations due to chance rather than natural selection. It may cause the change in the gene pool by random sampling of a particular allele which may incur in deleting a particular gene. Hence option D is correct .

Hence option ‘D’ a smaller population is the correct answer.

Note: Genetic drift is also called Sewall Wright effect. The effects of genetic drift are most marked in very small isolated populations, although it occurs in all populations.It can be a principal force in the evolution of some populations.