PCB 4674 Evolution - Exam 2 Questions &
Answers | Grade A | 100% Correct – Florida
State University
1. If the frequency of a recessive allele (q) in a population in Hardy-Weinberg
equilibrium is 0.3, what is the frequency of the homozygous dominant
genotype?
A. 0.09
B. 0.42
C. 0.49
D. 0.70
Answer: C
Explanation: If q = 0.3, then p = 0.7. The frequency of homozygous dominant (p^2) is 0.7 *
0.7 = 0.49.
2. Which of the following is an assumption of the Hardy-Weinberg principle?
A. No migration (gene flow)
B. Non-random mating
C. Small population size
D. High mutation rates
Answer: A
Explanation: Hardy-Weinberg assumes no selection, no mutation, no migration, large
population size, and random mating.
,3. Genetic drift has the greatest impact on which type of populations?
A. Large populations
B. Populations in Hardy-Weinberg equilibrium
C. Populations with high gene flow
D. Small populations
Answer: D
Explanation: Genetic drift is a stochastic process that leads to larger fluctuations in allele
frequencies in small populations compared to large ones.
4. In a phylogeny, a group that includes a common ancestor and ALL of its
descendants is called:
A. Paraphyletic
B. Polyphyletic
C. Monophyletic
D. Homoplastic
Answer: C
Explanation: A monophyletic group (or clade) consists of an ancestral species and all its
descendants.
5. The ‘effective population size’ (Ne) is usually:
A. Larger than the census population size (N)
B. Smaller than the census population size (N)
C. Equal to the census population size (N)
D. Unaffected by skewed sex ratios
Answer: B
Explanation: Factors like unequal sex ratios and high variance in reproductive success
typically make Ne smaller than the total count of individuals (N).
, 6. What is a ‘synapomorphy’?
A. A shared primitive character state
B. A character state unique to one terminal taxon
C. A shared derived character state
D. The independent evolution of similar traits
Answer: C
Explanation: Synapomorphies are shared derived traits used to define clades in
phylogenetic reconstruction.
7. The Neutral Theory of Molecular Evolution suggests that most evolutionary
changes at the molecular level are caused by:
A. Natural selection
B. Environmental stress
C. Sexual selection
D. Genetic drift of neutral mutations
Answer: D
Explanation: Kimura’s Neutral Theory posits that most molecular variation and
divergence are due to drift rather than selection.
8. In Hamilton’s Rule (rb > c), what does ‘r’ represent?
A. The cost to the actor
B. The coefficient of relatedness
C. The benefit to the recipient
D. The rate of mutation
Answer: B
Explanation: r is the probability that the homologous alleles in two individuals are
identical by descent.
Answers | Grade A | 100% Correct – Florida
State University
1. If the frequency of a recessive allele (q) in a population in Hardy-Weinberg
equilibrium is 0.3, what is the frequency of the homozygous dominant
genotype?
A. 0.09
B. 0.42
C. 0.49
D. 0.70
Answer: C
Explanation: If q = 0.3, then p = 0.7. The frequency of homozygous dominant (p^2) is 0.7 *
0.7 = 0.49.
2. Which of the following is an assumption of the Hardy-Weinberg principle?
A. No migration (gene flow)
B. Non-random mating
C. Small population size
D. High mutation rates
Answer: A
Explanation: Hardy-Weinberg assumes no selection, no mutation, no migration, large
population size, and random mating.
,3. Genetic drift has the greatest impact on which type of populations?
A. Large populations
B. Populations in Hardy-Weinberg equilibrium
C. Populations with high gene flow
D. Small populations
Answer: D
Explanation: Genetic drift is a stochastic process that leads to larger fluctuations in allele
frequencies in small populations compared to large ones.
4. In a phylogeny, a group that includes a common ancestor and ALL of its
descendants is called:
A. Paraphyletic
B. Polyphyletic
C. Monophyletic
D. Homoplastic
Answer: C
Explanation: A monophyletic group (or clade) consists of an ancestral species and all its
descendants.
5. The ‘effective population size’ (Ne) is usually:
A. Larger than the census population size (N)
B. Smaller than the census population size (N)
C. Equal to the census population size (N)
D. Unaffected by skewed sex ratios
Answer: B
Explanation: Factors like unequal sex ratios and high variance in reproductive success
typically make Ne smaller than the total count of individuals (N).
, 6. What is a ‘synapomorphy’?
A. A shared primitive character state
B. A character state unique to one terminal taxon
C. A shared derived character state
D. The independent evolution of similar traits
Answer: C
Explanation: Synapomorphies are shared derived traits used to define clades in
phylogenetic reconstruction.
7. The Neutral Theory of Molecular Evolution suggests that most evolutionary
changes at the molecular level are caused by:
A. Natural selection
B. Environmental stress
C. Sexual selection
D. Genetic drift of neutral mutations
Answer: D
Explanation: Kimura’s Neutral Theory posits that most molecular variation and
divergence are due to drift rather than selection.
8. In Hamilton’s Rule (rb > c), what does ‘r’ represent?
A. The cost to the actor
B. The coefficient of relatedness
C. The benefit to the recipient
D. The rate of mutation
Answer: B
Explanation: r is the probability that the homologous alleles in two individuals are
identical by descent.
