Ch08

Question 1

Why isn’t selection eliminating such detrimental allele?

Answer 1

Because of random effects due to small population size

Question 2

What is the effect of using a small sample size instead of a large one in population experiment?

Answer 2

realized frequencies are not always close to the expected frequencies

Question 3

List the assumptions of the Wright-Fisher model

Answer 3

• No natural selection
• Random mating
• No mutation
• No migration
• small population size

Question 4

Define genetic drift

Answer 4

the process of random fluctuations in allele frequencies due to sampling effects in a finite population

Question 5

Is sampling error larger in small or large samples?

Answer 5

Small. The effect of genetic drift is stronger in small populations

Question 6

List the consequences of random genetic drift

Answer 6

1) allele frequencies fluctuate over time, even in absence of selection
2) Some alleles may be fixed & others lost, & heterozygotes frequency usually decreases (reduce genetic variation & heterozygotes)
3) Separate populations diverge in allele frequencies, that is: they vary independently

Question 7

Genetic diversity was positively correlated with island size. T or F?

Answer 7

True.

• Larger island => larger population => higher genetic diversity
• Smaller island => smaller population => lower genetic diversity

Question 8

Define population bottleneck

Answer 8

A brief period when population size is reduced. Can result in loss of alleles

Question 9

Define Founder effect

Answer 9

Sampling effect that occurs when a small number of individuals migrate & start a new population.
Small probability that allele frequencies will be equal in mainland & island

Question 10

Give one example of population bottleneck & founder effect

Answer 10

• strong bottleneck reduced heterozygosity in northern elephant seals
• Glaciers disappeared from Hudson Bay