PCB4674 Exam 2: Evolution Practice Quiz – GCU
1. Which of the following is a primary requirement for a population to be in
Hardy-Weinberg equilibrium?
A. Presence of natural selection
B. Infinite (or very large) population size
C. Non-random mating
D. High rates of mutation
Answer: B
Rationale: Hardy-Weinberg equilibrium assumes a very large population size to minimize
the effects of genetic drift.
2. In a population, what does the ‘q’ represent in the Hardy-Weinberg equation
(p + q = 1)?
A. Frequency of the dominant allele
B. Frequency of the recessive allele
C. Frequency of the homozygous dominant genotype
D. Frequency of the heterozygous genotype
Answer: B
Rationale: In population genetics, ‘p’ represents the frequency of the dominant allele and
‘q’ represents the frequency of the recessive allele.
,3. Which evolutionary force is most likely to decrease genetic variation within a
population but increase it between populations?
A. Gene flow
B. Mutation
C. Random mating
D. Genetic drift
Answer: D
Rationale: Genetic drift leads to the loss of alleles within a population (decreasing
variation) and causes populations to diverge from each other randomly.
4. The movement of alleles between populations through the migration of
individuals is known as:
A. Genetic drift
B. Founder effect
C. Gene flow
D. Bottleneck effect
Answer: C
Rationale: Gene flow is the transfer of genetic material from one population to another via
migration and subsequent breeding.
5. Which type of selection favors individuals at both extremes of a phenotypic
range over individuals with intermediate phenotypes?
A. Stabilizing selection
B. Directional selection
C. Disruptive selection
D. Negative frequency-dependent selection
Answer: C
Rationale: Disruptive (or diversifying) selection favors extreme traits at both ends of the
spectrum, potentially leading to speciation.
, 6. What is the ‘relative fitness’ of a genotype that produces 50 offspring if the
most successful genotype produces 100 offspring?
A. 1.0
B. 0.5
C. 2.0
D. 50
Answer: B
Rationale: Relative fitness is calculated by dividing the number of offspring of a genotype
by the number of offspring of the most fit genotype (50/100 = 0.5).
7. The ‘Biological Species Concept’ defines species primarily based on:
A. Reproductive isolation
B. Ecological niche
C. Morphological similarity
D. DNA sequence identity
Answer: A
Rationale: The Biological Species Concept defines a species as a group of individuals that
can interbreed and produce viable, fertile offspring but are isolated from other such
groups.
8. Which of the following is a pre-zygotic reproductive barrier?
A. Hybrid sterility
B. Temporal isolation
C. Hybrid breakdown
D. Reduced hybrid viability
Answer: B
Rationale: Temporal isolation is a pre-zygotic barrier because it prevents mating from
occurring in the first place due to differences in breeding timing.
1. Which of the following is a primary requirement for a population to be in
Hardy-Weinberg equilibrium?
A. Presence of natural selection
B. Infinite (or very large) population size
C. Non-random mating
D. High rates of mutation
Answer: B
Rationale: Hardy-Weinberg equilibrium assumes a very large population size to minimize
the effects of genetic drift.
2. In a population, what does the ‘q’ represent in the Hardy-Weinberg equation
(p + q = 1)?
A. Frequency of the dominant allele
B. Frequency of the recessive allele
C. Frequency of the homozygous dominant genotype
D. Frequency of the heterozygous genotype
Answer: B
Rationale: In population genetics, ‘p’ represents the frequency of the dominant allele and
‘q’ represents the frequency of the recessive allele.
,3. Which evolutionary force is most likely to decrease genetic variation within a
population but increase it between populations?
A. Gene flow
B. Mutation
C. Random mating
D. Genetic drift
Answer: D
Rationale: Genetic drift leads to the loss of alleles within a population (decreasing
variation) and causes populations to diverge from each other randomly.
4. The movement of alleles between populations through the migration of
individuals is known as:
A. Genetic drift
B. Founder effect
C. Gene flow
D. Bottleneck effect
Answer: C
Rationale: Gene flow is the transfer of genetic material from one population to another via
migration and subsequent breeding.
5. Which type of selection favors individuals at both extremes of a phenotypic
range over individuals with intermediate phenotypes?
A. Stabilizing selection
B. Directional selection
C. Disruptive selection
D. Negative frequency-dependent selection
Answer: C
Rationale: Disruptive (or diversifying) selection favors extreme traits at both ends of the
spectrum, potentially leading to speciation.
, 6. What is the ‘relative fitness’ of a genotype that produces 50 offspring if the
most successful genotype produces 100 offspring?
A. 1.0
B. 0.5
C. 2.0
D. 50
Answer: B
Rationale: Relative fitness is calculated by dividing the number of offspring of a genotype
by the number of offspring of the most fit genotype (50/100 = 0.5).
7. The ‘Biological Species Concept’ defines species primarily based on:
A. Reproductive isolation
B. Ecological niche
C. Morphological similarity
D. DNA sequence identity
Answer: A
Rationale: The Biological Species Concept defines a species as a group of individuals that
can interbreed and produce viable, fertile offspring but are isolated from other such
groups.
8. Which of the following is a pre-zygotic reproductive barrier?
A. Hybrid sterility
B. Temporal isolation
C. Hybrid breakdown
D. Reduced hybrid viability
Answer: B
Rationale: Temporal isolation is a pre-zygotic barrier because it prevents mating from
occurring in the first place due to differences in breeding timing.
