Question

QUESTION 49

Rapid changes in allelic frequencies by _____ take place in populations that are small.

A. mutation

B. inbreeding

C. genetic drift

D. outbreeding

E. natural selection

QUESTION 51

1. _____ refers to the situation where the heterozygote has a lower fitness than both homozygotes ( W ₁₁ > W ₁₂ < W ₂₂).

   	A.	Genetic rescue
   	B.	Hardy–Weinberg equilibrium
   	C.	Heterozygote superiority
   	D.	Overdominance
   	E.	Underdominance

Answer 1

Question 49

Rapid changes in allelic frequencies by _____ take place in populations that are small.

Answer : C. Genetic Drift

Explanation :

Genetic drift is a change in the frequency of an allele within a population over time. This change in the frequency of the allele or gene variation must occur randomly in order for genetic drift to occur. These changes in relative allele frequency, can either increase or decrease by chance over time. Although genetic drift happens in populations of all sizes, its effects tend to be stronger in small populations. Smaller populations are more likely to be affected by chance events, since there are not as many alleles to “balance out” random changes in allele frequencies.

Question 51

_____ refers to the situation where the heterozygote has a lower fitness than both homozygotes ( W 11 > W 12 < W 22).

Answer : E. Underdominance

Explanation :

Underdominance (or "negative overdominance") is the opposite of overdominance. It is the selection against the heterozygote, causing disruptive selection and divergent genotypes. Underdominance exists in situations where the heterozygotic genotype is inferior in fitness to either the dominant or recessive homozygotic genotype.