PCB4674 Exam 1: Evolutionary Biology 2026 – FSU
1. Which of the following is the primary mechanism of evolution proposed by
Charles Darwin?
A. Genetic drift
B. Inheritance of acquired characteristics
C. Natural selection
D. Gene flow
Answer: C
Rationale: Charles Darwin proposed natural selection as the primary mechanism for
evolution in ‘On the Origin of Species’.
2. Who independently arrived at the same conclusions as Darwin regarding
natural selection?
A. Alfred Russel Wallace
B. Jean-Baptiste Lamarck
C. Gregor Mendel
D. Thomas Malthus
Answer: A
Rationale: Alfred Russel Wallace developed similar ideas about natural selection, leading
to a joint presentation of their findings.
,3. The fitness of an individual is best measured by:
A. Its physical strength and speed
B. Its lifespan
C. Its reproductive success relative to others
D. The number of mutations it carries
Answer: C
Rationale: In evolutionary biology, fitness refers to the contribution an individual makes
to the gene pool of the next generation.
4. Which type of selection favors individuals at both extremes of a phenotypic
range?
A. Directional selection
B. Disruptive selection
C. Stabilizing selection
D. Frequency-dependent selection
Answer: B
Rationale: Disruptive selection favors the extremes and acts against the intermediate
phenotypes.
5. The Hardy-Weinberg equilibrium principle acts as a null model to show:
A. The expected allele frequencies if no evolution occurs
B. How evolution occurs rapidly
C. The rate of mutation in a population
D. The effect of environmental selection
Answer: A
Rationale: Hardy-Weinberg describes a population that is not evolving, providing a
baseline to compare against real populations.
, 6. A sudden reduction in population size due to a natural disaster is known as:
A. The founder effect
B. Gene flow
C. Stabilizing selection
D. A population bottleneck
Answer: D
Rationale: A population bottleneck occurs when a population’s size is reduced for at least
one generation, significantly reducing genetic variation.
7. In a population of 100 individuals, if the frequency of the recessive allele (q) is
0.3, what is the frequency of the dominant allele (p)?
A. 0.09
B. 0.49
C. 0.7
D. 0.5
Answer: C
Rationale: Since p + q = 1, then p = 1 - 0.3 = 0.7.
8. Homologous structures are evidence of:
A. Common ancestry
B. Convergent evolution
C. Genetic drift
D. Analogy
Answer: A
Rationale: Homologous structures share a common origin even if they serve different
functions in modern species.
1. Which of the following is the primary mechanism of evolution proposed by
Charles Darwin?
A. Genetic drift
B. Inheritance of acquired characteristics
C. Natural selection
D. Gene flow
Answer: C
Rationale: Charles Darwin proposed natural selection as the primary mechanism for
evolution in ‘On the Origin of Species’.
2. Who independently arrived at the same conclusions as Darwin regarding
natural selection?
A. Alfred Russel Wallace
B. Jean-Baptiste Lamarck
C. Gregor Mendel
D. Thomas Malthus
Answer: A
Rationale: Alfred Russel Wallace developed similar ideas about natural selection, leading
to a joint presentation of their findings.
,3. The fitness of an individual is best measured by:
A. Its physical strength and speed
B. Its lifespan
C. Its reproductive success relative to others
D. The number of mutations it carries
Answer: C
Rationale: In evolutionary biology, fitness refers to the contribution an individual makes
to the gene pool of the next generation.
4. Which type of selection favors individuals at both extremes of a phenotypic
range?
A. Directional selection
B. Disruptive selection
C. Stabilizing selection
D. Frequency-dependent selection
Answer: B
Rationale: Disruptive selection favors the extremes and acts against the intermediate
phenotypes.
5. The Hardy-Weinberg equilibrium principle acts as a null model to show:
A. The expected allele frequencies if no evolution occurs
B. How evolution occurs rapidly
C. The rate of mutation in a population
D. The effect of environmental selection
Answer: A
Rationale: Hardy-Weinberg describes a population that is not evolving, providing a
baseline to compare against real populations.
, 6. A sudden reduction in population size due to a natural disaster is known as:
A. The founder effect
B. Gene flow
C. Stabilizing selection
D. A population bottleneck
Answer: D
Rationale: A population bottleneck occurs when a population’s size is reduced for at least
one generation, significantly reducing genetic variation.
7. In a population of 100 individuals, if the frequency of the recessive allele (q) is
0.3, what is the frequency of the dominant allele (p)?
A. 0.09
B. 0.49
C. 0.7
D. 0.5
Answer: C
Rationale: Since p + q = 1, then p = 1 - 0.3 = 0.7.
8. Homologous structures are evidence of:
A. Common ancestry
B. Convergent evolution
C. Genetic drift
D. Analogy
Answer: A
Rationale: Homologous structures share a common origin even if they serve different
functions in modern species.
