Question

The Barton Springs salamander is an endangered species found only in a single spring in the city of Austin, Texas. There is growing concern that a chemical spill on a nearby freeway could pollute the spring and wipe out the species. To provide a source of salamanders to repopulate the spring in the event of such a catastrophe, a proposal has been made to establish a captive breeding population of the salamander in a local zoo. Suppose you are asked to provide a plan for establishing this captive breeding population, with the goal of maintaining as much of the genetic variation of the species as possible in the captive population.

What factors are likely to lead to a loss of genetic variation in the captive population?
a. increased rate of mutation
b. a founder effect
c. reduced genetic drift over time
d. a lack of inbreeding
What strategy would likely be effective in mitigating the loss of genetic variation in the captive population? a. keeping the sex ratio as close to 50:50 as possible
b. stopping gene flow to and from the captive population
c. regularly mating individuals that are related
d. keeping the captive population as small as possible

Answer 1

1. b. a founder effect

2. a. keeping the sex ratio as close to 50:50 as possible

Step-by-step explanation:

The founder effect is a phenomenon that occurs when a small subset of individuals split from a larger population in order to establish a new colony. The founder effect is known to cause a reduction in genetic variation of the colony due to genetic drift, i.e., due to the random sampling of the individuals that form the colony (which doesn't reflect the total genetic diversity of the original population). Moreover, the sex ratio refers to the proportion of males to females in a population. When establishing a captive population, it is recommended to maintain a sex ratio as close to 50:50 as possible because it reduces inbreeding, and thereby mitigating the loss of genetic variation. In some populations, it has been proposed that a 50:50 sex-ratio might also increase the competition between males, which is believed to be fundamental for maintaining a healthy genetic structure of the population.