Environment & Ecology question from JKAS Prelims, 2021 by JKPSC
The loss of genetic diversity in an isolated small population could be attributed to:
1) Mutation
2) Inbreeding
3) Speciation
4) Genetic drift
Last updated May 13, 2026
Correct Answer:
Option C —
2 and 4
In small, isolated populations, genetic diversity tends to decrease over time due to specific evolutionary mechanisms:
Statement 4 (Genetic Drift): This is the random change in allele frequencies. In a small population, chance events can cause certain alleles to disappear entirely or others to become "fixed" (the only version remaining). Because there are fewer individuals to buffer these random changes, genetic drift has a much more pronounced effect.
Statement 2 (Inbreeding): Small, isolated populations have a limited pool of potential mates. This often leads to mating between closely related individuals. Over generations, inbreeding increases homozygosity and reduces the overall genetic variation within the population, often leading to the expression of harmful recessive traits (inbreeding depression).
Why the others are incorrect:
Statement 1 (Mutation): Mutations actually increase genetic diversity by introducing new alleles into a population.
Statement 3 (Speciation): Speciation is the process by which new species are formed. While it involves changes in genetic makeup, it is a result of evolutionary processes rather than a direct cause for the loss of diversity within a single population.
Answer verified by Quintessence Classes faculty — Karan Nagar, Srinagar.
