Issues Facing Small Populations

Question 1

What is the minimum viable population?

Answer 1

The smallest population size which can be expected to have a high chance of persisting into the foreseeable future.

Question 2

How can we determine the minimum viable population?

Answer 2

• Experiments
• Biogeographic patterns
• Theoretical models
• Simulation models.

Question 3

What are sources of uncertainty in terms of the minimum viable population?

Answer 3

• Demographic stochasticity
• Environmental stochasticity
• Natural catastrophes
• Genetic stochasticity.

Question 4

What is the Allee Effect?

Answer 4

Population sizes become so low that the social structure of populations becomes disrupted.

Question 5

What is genetic drift?

Answer 5

The random fluctuations in the numbers of gene variants in a population.

Question 6

Define outbreeding.

Answer 6

The breeding or mating of distantly related or unrelated individuals.

Question 7

Define inbreeding depression.

Answer 7

The decrease in heterozygosity of alleles in a gene pool due to continuous interbreeding between relatives.

Question 8

What are some of the implications of small population size?

Answer 8

• Inbreeding depression
• Outbreeding
• Genetic Drift
• Allee effect.

Question 9

What is Franklin’s 50/500 rule?

Answer 9

The 50 relates to inbreeding depression and the 500 relates to genetic drift. It is thought that the rule should be changed to 100/1000 as the original rule was derived from domestic animal breeders.

Question 10

What is the ‘Founder Effect’?

Answer 10

Occurs when a few individuals leave one

population to establish a new population.