PCB4674 Exam 2: Evolution Comprehensive Practice 2026 – FSU
1. Which of the following describes a monophyletic group?
A. A group consisting of an ancestor and some, but not all, of its descendants
B. A group based on convergent characteristics rather than common ancestry
C. A group that includes an ancestor and all of its descendants
D. A group that does not include the most recent common ancestor
Answer: C
Rationale: A monophyletic group, or clade, includes the most recent common ancestor and
all of its descendants.
2. What is the term for a shared derived character state used to define a clade?
A. Symplesiomorphy
B. Synapomorphy
C. Autapomorphy
D. Homoplasy
Answer: B
Rationale: Synapomorphies are shared derived characters that provide evidence for the
common ancestry of a group.
3. In phylogenetic trees, what does a ‘node’ represent?
A. An extant species
B. A common ancestor where a lineage splits
C. The rate of mutation
D. A terminal taxon
Answer: B
,Rationale: Nodes represent the most recent common ancestor of the lineages that branch
off from that point.
4. Which principle suggests that the simplest explanation with the fewest
evolutionary changes is the most likely?
A. Maximum Likelihood
B. Bayesian Inference
C. Genetic Drift
D. Parsimony
Answer: D
Rationale: Parsimony (Occam’s Razor) assumes that the tree requiring the fewest
character state changes is the best hypothesis.
5. What is ‘vicariance’ in the context of speciation?
A. The movement of individuals to a new isolated island
B. Rapid evolution due to sexual selection
C. Speciation occurring within the same geographic area
D. The physical splitting of a population’s habitat by a geographic barrier
Answer: D
Rationale: Vicariance occurs when a geographic barrier, like a mountain range or river,
emerges and splits a continuous population.
6. Which species concept defines a species based on the ability of individuals to
interbreed and produce fertile offspring?
A. Morphological Species Concept
B. Biological Species Concept
C. Phylogenetic Species Concept
D. Ecological Species Concept
Answer: B
, Rationale: The Biological Species Concept, proposed by Ernst Mayr, focuses on
reproductive isolation.
7. What is the primary cause of allopatric speciation?
A. Polyploidy
B. Geographic isolation
C. Disruptive selection in the same lake
D. Horizontal gene transfer
Answer: B
Rationale: Allopatric speciation happens when populations are physically separated by a
geographic barrier.
8. Which of the following is a post-zygotic isolating mechanism?
A. Temporal isolation
B. Behavioral isolation
C. Hybrid sterility
D. Gametic incompatibility
Answer: C
Rationale: Hybrid sterility (like a mule) occurs after fertilization and prevents the hybrid
from reproducing.
9. What does ‘reinforcement’ refer to in the study of speciation?
A. Fixation of beneficial mutations in a large population
B. The strengthening of a geographic barrier over time
C. The increase in gene flow between two diverging populations
D. Selection for pre-zygotic isolation to prevent the production of low-fitness hybrids
Answer: D
Rationale: Reinforcement is the process by which natural selection increases reproductive
isolation between two populations after they come back into contact.
1. Which of the following describes a monophyletic group?
A. A group consisting of an ancestor and some, but not all, of its descendants
B. A group based on convergent characteristics rather than common ancestry
C. A group that includes an ancestor and all of its descendants
D. A group that does not include the most recent common ancestor
Answer: C
Rationale: A monophyletic group, or clade, includes the most recent common ancestor and
all of its descendants.
2. What is the term for a shared derived character state used to define a clade?
A. Symplesiomorphy
B. Synapomorphy
C. Autapomorphy
D. Homoplasy
Answer: B
Rationale: Synapomorphies are shared derived characters that provide evidence for the
common ancestry of a group.
3. In phylogenetic trees, what does a ‘node’ represent?
A. An extant species
B. A common ancestor where a lineage splits
C. The rate of mutation
D. A terminal taxon
Answer: B
,Rationale: Nodes represent the most recent common ancestor of the lineages that branch
off from that point.
4. Which principle suggests that the simplest explanation with the fewest
evolutionary changes is the most likely?
A. Maximum Likelihood
B. Bayesian Inference
C. Genetic Drift
D. Parsimony
Answer: D
Rationale: Parsimony (Occam’s Razor) assumes that the tree requiring the fewest
character state changes is the best hypothesis.
5. What is ‘vicariance’ in the context of speciation?
A. The movement of individuals to a new isolated island
B. Rapid evolution due to sexual selection
C. Speciation occurring within the same geographic area
D. The physical splitting of a population’s habitat by a geographic barrier
Answer: D
Rationale: Vicariance occurs when a geographic barrier, like a mountain range or river,
emerges and splits a continuous population.
6. Which species concept defines a species based on the ability of individuals to
interbreed and produce fertile offspring?
A. Morphological Species Concept
B. Biological Species Concept
C. Phylogenetic Species Concept
D. Ecological Species Concept
Answer: B
, Rationale: The Biological Species Concept, proposed by Ernst Mayr, focuses on
reproductive isolation.
7. What is the primary cause of allopatric speciation?
A. Polyploidy
B. Geographic isolation
C. Disruptive selection in the same lake
D. Horizontal gene transfer
Answer: B
Rationale: Allopatric speciation happens when populations are physically separated by a
geographic barrier.
8. Which of the following is a post-zygotic isolating mechanism?
A. Temporal isolation
B. Behavioral isolation
C. Hybrid sterility
D. Gametic incompatibility
Answer: C
Rationale: Hybrid sterility (like a mule) occurs after fertilization and prevents the hybrid
from reproducing.
9. What does ‘reinforcement’ refer to in the study of speciation?
A. Fixation of beneficial mutations in a large population
B. The strengthening of a geographic barrier over time
C. The increase in gene flow between two diverging populations
D. Selection for pre-zygotic isolation to prevent the production of low-fitness hybrids
Answer: D
Rationale: Reinforcement is the process by which natural selection increases reproductive
isolation between two populations after they come back into contact.
