Evolution Final Exam (PCB4674) - 2026/2027 Edition FSU
1. Which of the following describes a synapomorphy?
A. A trait shared by a group of organisms and their common ancestor, which is also shared with more distant
ancestors
B. The independent evolution of similar features in species of different lineages
C. A derived character state that is shared by two or more taxa and is postulated to have evolved in their
common ancestor
D. A character state that is unique to a single terminal taxon
Answer: C
Rationale: A synapomorphy is a shared derived trait that defines a clade and distinguishes
it from other groups.
2. In the Hardy-Weinberg equilibrium equation (p^2 + 2pq + q^2 = 1), what does
the term ‘2pq’ represent?
A. The frequency of the homozygous dominant genotype
B. The frequency of the dominant allele
C. The frequency of the homozygous recessive genotype
D. The frequency of the heterozygous genotype
Answer: D
Rationale: The term 2pq represents the frequency of heterozygotes in a population at
equilibrium.
,3. Which evolutionary mechanism is primarily responsible for the ‘Founder
Effect’?
A. Natural Selection
B. Genetic Drift
C. Gene Flow
D. Mutation
Answer: B
Rationale: The founder effect is a form of genetic drift that occurs when a small group of
individuals establishes a new population, carrying only a fraction of the original genetic
diversity.
4. Which type of selection occurs when individuals at both extremes of a
phenotypic range have higher fitness than individuals with intermediate
phenotypes?
A. Stabilizing Selection
B. Disruptive Selection
C. Directional Selection
D. Balancing Selection
Answer: B
Rationale: Disruptive (or diversifying) selection favors both extremes and acts against the
mean.
5. What is the primary difference between allopatric and sympatric speciation?
A. The rate at which mutations occur
B. The degree of sexual selection
C. The number of chromosomes involved
D. The presence or absence of geographic barriers
Answer: D
, Rationale: Allopatric speciation involves geographic isolation, whereas sympatric
speciation occurs within the same geographic area.
6. According to the Biological Species Concept, what defines a species?
A. Morphological similarity
B. Shared ecological niche
C. Genetic divergence exceeding a 5% threshold
D. Actual or potential interbreeding leading to viable, fertile offspring
Answer: D
Rationale: The Biological Species Concept focuses on reproductive isolation as the primary
criterion for defining species.
7. What does a dN/dS ratio greater than 1 (>1) typically indicate in molecular
evolution?
A. Purifying (negative) selection
B. Neutral evolution
C. High levels of genetic drift
D. Positive (diversifying) selection
Answer: D
Rationale: A dN/dS ratio > 1 indicates that non-synonymous mutations are being fixed
faster than synonymous ones, suggesting positive selection for change.
8. Which term describes a group of organisms that includes an ancestor but not
all of its descendants?
A. Monophyletic
B. Polyphyletic
C. Holophyletic
D. Paraphyletic
Answer: D
1. Which of the following describes a synapomorphy?
A. A trait shared by a group of organisms and their common ancestor, which is also shared with more distant
ancestors
B. The independent evolution of similar features in species of different lineages
C. A derived character state that is shared by two or more taxa and is postulated to have evolved in their
common ancestor
D. A character state that is unique to a single terminal taxon
Answer: C
Rationale: A synapomorphy is a shared derived trait that defines a clade and distinguishes
it from other groups.
2. In the Hardy-Weinberg equilibrium equation (p^2 + 2pq + q^2 = 1), what does
the term ‘2pq’ represent?
A. The frequency of the homozygous dominant genotype
B. The frequency of the dominant allele
C. The frequency of the homozygous recessive genotype
D. The frequency of the heterozygous genotype
Answer: D
Rationale: The term 2pq represents the frequency of heterozygotes in a population at
equilibrium.
,3. Which evolutionary mechanism is primarily responsible for the ‘Founder
Effect’?
A. Natural Selection
B. Genetic Drift
C. Gene Flow
D. Mutation
Answer: B
Rationale: The founder effect is a form of genetic drift that occurs when a small group of
individuals establishes a new population, carrying only a fraction of the original genetic
diversity.
4. Which type of selection occurs when individuals at both extremes of a
phenotypic range have higher fitness than individuals with intermediate
phenotypes?
A. Stabilizing Selection
B. Disruptive Selection
C. Directional Selection
D. Balancing Selection
Answer: B
Rationale: Disruptive (or diversifying) selection favors both extremes and acts against the
mean.
5. What is the primary difference between allopatric and sympatric speciation?
A. The rate at which mutations occur
B. The degree of sexual selection
C. The number of chromosomes involved
D. The presence or absence of geographic barriers
Answer: D
, Rationale: Allopatric speciation involves geographic isolation, whereas sympatric
speciation occurs within the same geographic area.
6. According to the Biological Species Concept, what defines a species?
A. Morphological similarity
B. Shared ecological niche
C. Genetic divergence exceeding a 5% threshold
D. Actual or potential interbreeding leading to viable, fertile offspring
Answer: D
Rationale: The Biological Species Concept focuses on reproductive isolation as the primary
criterion for defining species.
7. What does a dN/dS ratio greater than 1 (>1) typically indicate in molecular
evolution?
A. Purifying (negative) selection
B. Neutral evolution
C. High levels of genetic drift
D. Positive (diversifying) selection
Answer: D
Rationale: A dN/dS ratio > 1 indicates that non-synonymous mutations are being fixed
faster than synonymous ones, suggesting positive selection for change.
8. Which term describes a group of organisms that includes an ancestor but not
all of its descendants?
A. Monophyletic
B. Polyphyletic
C. Holophyletic
D. Paraphyletic
Answer: D
