Question 1

Survival is the single most important process in evolution by natural selection.

Accepted Answer

A) True 
 B)False

Question 2

A gene is known to have three alleles: p,q,and r.The frequency of p is estimated at 0.70.Thus,the frequencies or q and r must be 0.15 each.

Accepted Answer

A) True 
 B)False

Question 3

Observed genotypic frequencies in populations rarely match

Accepted Answer

The answer of Observed genotypic frequencies in populations rarely match...

Question 4

Genetic drift may lead to

Accepted Answer

A) loss of genetic variation in a population. 
B) a decrease in the mutation rate of a particular gene. 
C) increased heterozygosity at many loci.

Question 5

With respect to a gene with two alleles,for each generation of complete inbreeding the proportion of heterozygotes is expected to be reduced by $\frac { 1 } { 2 }$ while the proportion of each homozygous class is expected to increase in frequency by $\frac { 1 } { 4 }$ .Explain why this is so.

Accepted Answer

The answer of With respect to a gene with two...

Question 6

In a population of frogs,RR homozygotes produce an average of 5 offspring that survive to reproduce.Rr frogs produce 4,and rr frogs produce 1.The fitness of the three genotypes w11,w12,and w22 are respectively

Accepted Answer

A) 5,4,and 1. 
B) 0.5,0.4,and 0.1. 
C) 1.0.,0.8,and 0.2. 
D) 0.5,1.0,and 0.1. 
E) None of these

Question 7

For which of the following traits is human mating expected to be nonrandom?

Accepted Answer

A) Blood type 
B) Isocitrate dehydrogenase enzyme 
C) Skin color 
D) Presence or absence of a widow's peak 
E) Fingerprint loci

Question 8

A population genetic study of a certain insect revealed four alleles for the GPI (glucose-phosphate isomerase)locus.How many different genotypic classes should be found?

Accepted Answer

A) 4 
B) 8 
C) 10 
D) 16 
E) 20

Question 9

Which of the following is not a form of genetic drift?

Accepted Answer

A) Founder effect 
B) Nonrandom mating 
C) Population bottleneck 
D) Heterozygote advantage 
E) All of these are forms of genetic drift.

Question 10

Heterozygotes for the sickle-cell allele show higher fitness than either homozygote genotype in malarial regions.This is an example of

Accepted Answer

A) epistasis. 
B) pleiotropy. 
C) founder effect. 
D) overdominance. 
E) codominance.

Question 11

This chapter discussed speciation by genetic divergence following geographic isolation,which is expected to lead to reduced gene flow,a process known as allopatric speciation.A more controversial form of speciation is the genetic divergence of populations without physical isolation,a process known as sympatric speciation.Can you envision a mechanism or process that would permit two coexisting populations of the same species to begin to diverge without being isolated from one another?

Accepted Answer

The answer of This chapter discussed speciation by genetic divergence...

Question 12

Why do we expect that postzygotic isolation will evolutionarily precede prezygotic isolation in the speciation process?

Accepted Answer

The answer of Why do we expect that postzygotic isolation...

Question 13

Populations that suffer significant reductions in number may experience two population-genetic consequences that together can hasten their decline.Which two processes are likely to act in concert in small populations,and what is their effect?

Accepted Answer

The answer of Populations that suffer significant reductions in number...

Question 14

Twenty loci are screened for genetic variation in a common caterpillar species.Four loci are found to have two or more alleles.The proportion of polymorphic loci for this population is thus

Accepted Answer

A) 0.10. 
B) 0.20. 
C) 0.30. 
D) 0.40. 
E) 0.50.

Question 15

In light of the fact that the assumptions of the

Accepted Answer

The answer of In light of the fact that the...

Question 16

Synonymous mutations are found much more frequently than nonsynonymous mutations because

Accepted Answer

A) mutations do not occur randomly 
B) the genetic code is redundant. 
C) of genetic drift. 
D) there is a selective advantage in looking like another species. 
E) changes in the amino acid sequence of proteins are likely to be harmful.

Question 17

According to the Hardy-Weinberg principle, at equilibrium the allele frequencies are dependent on the genotypic frequencies.

Accepted Answer

A) True 
 B)False

Question 18

In reciprocal hybrid crosses,the heterogametic sex is typically sterile while the homogametic sex is not.This phenomenon is referred to as

Accepted Answer

A) hybrid incompatibility. 
B) postzygotic isolation. 
C) Haldane's rule. 
D) male sterility. 
E) None of these

Question 19

Remote oceanic islands are characterized as having disharmonic biota,meaning the number and relative proportions of taxa living on the island differ significantly from the number and relative proportions of taxa on the nearest continental mainland area.Each island system is disharmonic in its own unique way.Why?

Accepted Answer

The answer of Remote oceanic islands are characterized as having...

Question 20

The frequency of a recessive X-linked allele is equal to the phenotypic frequency of males exhibiting that allele.

Accepted Answer

A) True 
 B)False

Exam 21: Population Genetics

Survival is the single most important process in evolution by natural selection.

A gene is known to have three alleles: p,q,and r.The frequency of p is estimated at 0.70.Thus,the frequencies or q and r must be 0.15 each.

Observed genotypic frequencies in populations rarely match

Genetic drift may lead to

With respect to a gene with two alleles,for each generation of complete inbreeding the proportion of heterozygotes is expected to be reduced by $\frac { 1 } { 2 }$ while the proportion of each homozygous class is expected to increase in frequency by $\frac { 1 } { 4 }$ .Explain why this is so.

In a population of frogs,RR homozygotes produce an average of 5 offspring that survive to reproduce.Rr frogs produce 4,and rr frogs produce 1.The fitness of the three genotypes w₁₁,w₁₂,and w₂₂ are respectively

For which of the following traits is human mating expected to be nonrandom?

A population genetic study of a certain insect revealed four alleles for the GPI (glucose-phosphate isomerase) locus.How many different genotypic classes should be found?

Which of the following is not a form of genetic drift?

Heterozygotes for the sickle-cell allele show higher fitness than either homozygote genotype in malarial regions.This is an example of

Why do we expect that postzygotic isolation will evolutionarily precede prezygotic isolation in the speciation process?

Populations that suffer significant reductions in number may experience two population-genetic consequences that together can hasten their decline.Which two processes are likely to act in concert in small populations,and what is their effect?

Twenty loci are screened for genetic variation in a common caterpillar species.Four loci are found to have two or more alleles.The proportion of polymorphic loci for this population is thus

In light of the fact that the assumptions of the

Synonymous mutations are found much more frequently than nonsynonymous mutations because

According to the Hardy-Weinberg principle, at equilibrium the allele frequencies are dependent on the genotypic frequencies.

In reciprocal hybrid crosses,the heterogametic sex is typically sterile while the homogametic sex is not.This phenomenon is referred to as

The frequency of a recessive X-linked allele is equal to the phenotypic frequency of males exhibiting that allele.