A researcher returns from the Amazon River with 10 individuals of a species of fish and establishes a small breeding colony in her laboratory. She maintains the colony for several years (many fish generations), always maintaining the number of adult fish between 10 and 30. She notices that as generations of fish are bred, the reproductive rate decreases. What is the most likely reason for this?
A) inbreeding depression
B) increased genetic variability
C) random mutations
D) heterozygote advantage

Question

Quizplus · Accepted Answer

Inbreeding depression occurs when closely related individuals mate and produce offspring with reduced fitness. Over time, the breeding colony in the laboratory likely experienced increased relatedness among individuals, leading to inbreeding and decreased reproductive rate. This is a common problem in small, isolated populations such as those maintained in laboratory colonies. Increased genetic variability (B) and random mutations (C) can lead to the generation of new traits, but are less likely to be the cause of decreased reproductive rate. Heterozygote advantage (D) occurs when heterozygous individuals have higher fitness than homozygous individuals, but this is not necessarily related to the observed decrease in reproductive rate.

A Researcher Returns from the Amazon River with 10 Individuals