The effective population size is often lower than the census size of a population because
A) inbreeding depression decreases the fitness of inbred progeny.
B) populations cannot recover from decreases in heterozygosity.
C) scientists cannot accurately count the number of individuals in a population.
D) individuals contribute unequally to future generations.

Question

Quizplus · Accepted Answer

The effective population size takes into account the fact that not all individuals in a population contribute equally to the next generation, and some may not reproduce at all. This can lead to a decrease in genetic diversity and an increase in inbreeding, which can have negative fitness effects. Inbreeding depression (A) and decreases in heterozygosity (B) are consequences of a low effective population size, but they do not explain why the effective population size is lower than the census size. The accuracy of counting individuals (C) may affect the precision of estimates but does not account for the difference between census and effective population size.

The Effective Population Size Is Often Lower Than the Census