NEET BIOLOGY

Detailed explanation-1: -The bottleneck effect is an extreme example of genetic drift that happens when the size of a population is severely reduced. Events like natural disasters (earthquakes, floods, fires) can decimate a population, killing most individuals and leaving behind a small, random assortment of survivors.

Detailed explanation-2: -Random sampling occurs whenever a smaller number of successful individuals (or gametes) are sampled from a larger pool of potential survivers and the fitnesses of the genotypes are the same. Random sampling works at every stage as a new generation grows up but it starts at conception.

Detailed explanation-3: -For example: When people who have the gene causing a specific genetic trait, like freckles, reproduce with people who do not have the gene, the gene can become more popular (nearly everyone in that population has freckles) or totally disappear from the population (no one has freckles).