Evolution Exam 2 - PCB4674 2026 – FSU
1. Which of the following is defined as a shared, derived character state that
provides evidence of common ancestry?
A. Synapomorphy
B. Symplesiomorphy
C. Homoplasy
D. Autapomorphy
Answer: A
Rationale: Synapomorphies are shared derived traits used to define clades and determine
phylogenetic relationships.
2. In which scenario is genetic drift most likely to have the largest impact on
allele frequencies?
A. A small population undergoing a bottleneck
B. A large population with high gene flow
C. A population under strong directional selection
D. A population in Hardy-Weinberg equilibrium
Answer: A
Rationale: Genetic drift is a stochastic process that has significantly more influence in
small populations or during bottleneck events.
,3. The Biological Species Concept (BSC) defines species primarily based on which
of the following?
A. Morphological similarity
B. Reproductive isolation
C. Ecological niche
D. Phylogenetic history
Answer: B
Rationale: The BSC defines a species as a group of interbreeding natural populations that
are reproductively isolated from other such groups.
4. Which type of speciation occurs when populations are geographically
separated?
A. Sympatric speciation
B. Parapatric speciation
C. Peripatric speciation
D. Allopatric speciation
Answer: D
Rationale: Allopatric speciation occurs when a physical barrier divides a population,
preventing gene flow.
5. In a phylogenetic tree, what does a ‘node’ represent?
A. The extinction of a species
B. A specific character trait
C. The common ancestor of two or more lineages
D. A single living organism
Answer: C
Rationale: Nodes represent the most recent common ancestor of the descendant lineages
branching from that point.
, 6. What is the term for a group that includes an ancestor and all of its
descendants?
A. Polyphyletic
B. Paraphyletic
C. Outgroup
D. Monophyletic
Answer: D
Rationale: A monophyletic group, or clade, consists of an ancestral species and all its
descendants.
7. Which of the following is a pre-zygotic reproductive barrier?
A. Hybrid sterility
B. Hybrid inviability
C. Hybrid breakdown
D. Temporal isolation
Answer: D
Rationale: Temporal isolation prevents mating from occurring in the first place, making it
a pre-zygotic barrier.
8. The concept that most evolutionary changes at the molecular level are caused
by random drift of neutral mutants is known as:
A. The Neutral Theory of Molecular Evolution
B. The Theory of Natural Selection
C. Punctuated Equilibrium
D. Modern Synthesis
Answer: A
Rationale: The Neutral Theory, proposed by Motoo Kimura, suggests that most genetic
variation is neutral and driven by drift rather than selection.
1. Which of the following is defined as a shared, derived character state that
provides evidence of common ancestry?
A. Synapomorphy
B. Symplesiomorphy
C. Homoplasy
D. Autapomorphy
Answer: A
Rationale: Synapomorphies are shared derived traits used to define clades and determine
phylogenetic relationships.
2. In which scenario is genetic drift most likely to have the largest impact on
allele frequencies?
A. A small population undergoing a bottleneck
B. A large population with high gene flow
C. A population under strong directional selection
D. A population in Hardy-Weinberg equilibrium
Answer: A
Rationale: Genetic drift is a stochastic process that has significantly more influence in
small populations or during bottleneck events.
,3. The Biological Species Concept (BSC) defines species primarily based on which
of the following?
A. Morphological similarity
B. Reproductive isolation
C. Ecological niche
D. Phylogenetic history
Answer: B
Rationale: The BSC defines a species as a group of interbreeding natural populations that
are reproductively isolated from other such groups.
4. Which type of speciation occurs when populations are geographically
separated?
A. Sympatric speciation
B. Parapatric speciation
C. Peripatric speciation
D. Allopatric speciation
Answer: D
Rationale: Allopatric speciation occurs when a physical barrier divides a population,
preventing gene flow.
5. In a phylogenetic tree, what does a ‘node’ represent?
A. The extinction of a species
B. A specific character trait
C. The common ancestor of two or more lineages
D. A single living organism
Answer: C
Rationale: Nodes represent the most recent common ancestor of the descendant lineages
branching from that point.
, 6. What is the term for a group that includes an ancestor and all of its
descendants?
A. Polyphyletic
B. Paraphyletic
C. Outgroup
D. Monophyletic
Answer: D
Rationale: A monophyletic group, or clade, consists of an ancestral species and all its
descendants.
7. Which of the following is a pre-zygotic reproductive barrier?
A. Hybrid sterility
B. Hybrid inviability
C. Hybrid breakdown
D. Temporal isolation
Answer: D
Rationale: Temporal isolation prevents mating from occurring in the first place, making it
a pre-zygotic barrier.
8. The concept that most evolutionary changes at the molecular level are caused
by random drift of neutral mutants is known as:
A. The Neutral Theory of Molecular Evolution
B. The Theory of Natural Selection
C. Punctuated Equilibrium
D. Modern Synthesis
Answer: A
Rationale: The Neutral Theory, proposed by Motoo Kimura, suggests that most genetic
variation is neutral and driven by drift rather than selection.
