Background: Declines in population size can result in a loss of genetic diversity, and owing to genetic variation's role in the evolutionary potential of a species, this could in turn result in an observable Allee effect. As a species' population becomes smaller, its gene pool will be reduced in size as well. One possible outcome from this genetic bottleneck is a reduction in fitness of the species through the process of genetic drift, as well as inbreeding depression. This overall fitness decrease of a species is caused by an accumulation of deleterious mutations throughout the population. Genetic variation within a species could range from beneficial to detrimental. Nevertheless, in a smaller sized gene pool, there is a higher chance of a stochastic event in which deleterious alleles become fixed (genetic drift). While evolutionary theory states that expressed deleterious alleles should be purged through natural selection, purging would be most efficient only at eliminating alleles that are highly detrimental or harmful. Mildly deleterious alleles such as those that act later in life would be less likely to be removed by natural selection, and conversely, newly acquired beneficial mutations are more likely to be lost by random chance in smaller genetic pools than larger ones.Although the long-term population persistence of several species with low genetic variation has recently prompted debate on the generality of inbreeding depression, there are various empirical evidences for genetic Allee effects. One such case was observed in the endangered Florida panther (Puma concolor coryi). The Florida panther experienced a genetic bottleneck in the early 1990s where the population was reduced to ≈25 adult individuals. This reduction in genetic diversity was correlated with defects that include lower sperm quality, abnormal testosterone levels, cowlicks, and kinked tails. In response, a genetic rescue plan was put in motion and several female pumas from Texas were introduced into the Florida population. This action quickly led to the reduction in the prevalence of the defects previously associated with inbreeding depression. Although the timescale for this inbreeding depression is larger than of those more immediate Allee effects, it has significant implications on the long-term persistence of a species.

Situation: Dan is a geneticist and studied two villages from 2,000 years ago. Village A displayed traces of a large population that grew larger over the years, while village B had a small and declining population and was more isolated geographically.

Question: Which village displayed a loss of genetic diversity?
Answer: village B

Situation: Dan is a geneticist and studied two villages from 2,000 years ago. Village A displayed traces of a large population that grew larger over the years, while village B had a small and declining population and was more isolated geographically.

Question: Which village didn't display a loss of genetic diversity?
Answer: Village A

Situation: Dan is a geneticist and studied two villages from 2,000 years ago. Village A displayed traces of a large population that grew larger over the years, while village B had a small and declining population and was more isolated geographically.

Question: Which village didn't display an observable Allee effect?
Answer: Village A

Situation: Dan is a geneticist and studied two villages from 2,000 years ago. Village A displayed traces of a large population that grew larger over the years, while village B had a small and declining population and was more isolated geographically.

Question: Which village displayed an observable Allee effect?
Answer: village B

Situation: Dan is a geneticist and studied two villages from 2,000 years ago. Village A displayed traces of a large population that grew larger over the years, while village B had a small and declining population and was more isolated geographically.

Question: Which village displayed a reduced gene pool?
Answer: village B

Situation: Dan is a geneticist and studied two villages from 2,000 years ago. Village A displayed traces of a large population that grew larger over the years, while village B had a small and declining population and was more isolated geographically.

Question: Which village didn't have a reduced gene pool?
Answer: Village A

Situation: Dan is a geneticist and studied two villages from 2,000 years ago. Village A displayed traces of a large population that grew larger over the years, while village B had a small and declining population and was more isolated geographically.

Question: Which village experienced a genetic bottleneck?
Answer: village B

Situation: Dan is a geneticist and studied two villages from 2,000 years ago. Village A displayed traces of a large population that grew larger over the years, while village B had a small and declining population and was more isolated geographically.

Question: Which village didn't experience a genetic bottleneck?
Answer: Village A

Situation: Dan is a geneticist and studied two villages from 2,000 years ago. Village A displayed traces of a large population that grew larger over the years, while village B had a small and declining population and was more isolated geographically.

Question: Which village didn't experience inbreeding depression?
Answer: Village A

Situation: Dan is a geneticist and studied two villages from 2,000 years ago. Village A displayed traces of a large population that grew larger over the years, while village B had a small and declining population and was more isolated geographically.

Question: Which village experienced inbreeding depression?
Answer: village B

Situation: Bobby and Will were two friends attending a genetics course.  Bobby studied a small, isolated group of mammals. Will studied a large, healthy population of the same species.

Question: Which person observed a loss in genetic diversity?
Answer: Bobby

Situation: Bobby and Will were two friends attending a genetics course.  Bobby studied a small, isolated group of mammals. Will studied a large, healthy population of the same species.

Question: Which person didn't observe any loss in genetic diversity?
Answer: Will

Situation: Bobby and Will were two friends attending a genetics course.  Bobby studied a small, isolated group of mammals. Will studied a large, healthy population of the same species.

Question: Which person learned more about an observable Allee effect?
Answer: Bobby

Situation: Bobby and Will were two friends attending a genetics course.  Bobby studied a small, isolated group of mammals. Will studied a large, healthy population of the same species.

Question: Which person learned less about an observable Allee effect?
Answer: Will

Situation: Bobby and Will were two friends attending a genetics course.  Bobby studied a small, isolated group of mammals. Will studied a large, healthy population of the same species.

Question: Which person observed a reduced gene pool size?
Answer: Bobby

Situation: Bobby and Will were two friends attending a genetics course.  Bobby studied a small, isolated group of mammals. Will studied a large, healthy population of the same species.

Question: Which person didn't observe a reduced gene pool size?
Answer: Will

Situation: Bobby and Will were two friends attending a genetics course.  Bobby studied a small, isolated group of mammals. Will studied a large, healthy population of the same species.

Question: Which person didn't observe a 'genetic bottleneck'?
Answer: Will

Situation: Bobby and Will were two friends attending a genetics course.  Bobby studied a small, isolated group of mammals. Will studied a large, healthy population of the same species.

Question: Which person observed a 'genetic bottleneck'?
Answer: Bobby

Situation: Bobby and Will were two friends attending a genetics course.  Bobby studied a small, isolated group of mammals. Will studied a large, healthy population of the same species.

Question: Which person observed a reduction in fitness of the species?
Answer: Bobby

Situation: Bobby and Will were two friends attending a genetics course.  Bobby studied a small, isolated group of mammals. Will studied a large, healthy population of the same species.

Question: Which person didn't observe a reduction in fitness of the species?
Answer: Will