PCB4674 Exam 2: Evolution Practice Quiz 2026 – FSU
1. Which mode of natural selection favors individuals at both extremes of a
phenotypic range over those with intermediate phenotypes?
A. Disruptive selection
B. Stabilizing selection
C. Directional selection
D. Balancing selection
Answer: A
Rationale: Disruptive selection (or diversifying selection) occurs when environmental
conditions favor individuals at both extremes of a phenotypic range over individuals with
intermediate phenotypes.
2. In a population of 1000 individuals, if the frequency of the recessive allele ‘a’
is 0.3, what is the expected number of homozygous dominant individuals under
Hardy-Weinberg equilibrium?
A. 420
B. 90
C. 700
D. 490
Answer: D
Rationale: If q = 0.3, then p = 0.7. The frequency of homozygous dominant individuals
(p^2) is 0.7 * 0.7 = 0.49. For 1000 individuals, 0.49 * 1000 = 490.
,3. Which of the following is the primary source of new genetic variation in a
population?
A. Genetic drift
B. Natural selection
C. Gene flow
D. Mutation
Answer: D
Rationale: Mutation is the ultimate source of all genetic variation, providing the raw
material upon which other evolutionary forces like selection and drift can act.
4. Genetic drift has the most significant impact on which type of population?
A. Large populations with high gene flow
B. Migratory populations
C. Populations in Hardy-Weinberg equilibrium
D. Small, isolated populations
Answer: D
Rationale: Genetic drift refers to random fluctuations in allele frequencies. These random
effects are much more pronounced and likely to lead to fixation or loss of alleles in small
populations.
5. Which phylogenetic term describes a group that includes a common ancestor
and all of its descendants?
A. Paraphyletic
B. Polyphyletic
C. Outgroup
D. Monophyletic
Answer: D
Rationale: A monophyletic group, or clade, consists of an ancestral species and all its
descendants, distinguished by shared derived characters (synapomorphies).
, 6. What is the ‘Biological Species Concept’ primarily based on?
A. Reproductive isolation
B. Ecological niche
C. Morphological similarity
D. Phylogenetic lineage
Answer: A
Rationale: The Biological Species Concept defines a species as a group of populations
whose members have the potential to interbreed in nature and produce viable, fertile
offspring.
7. The evolution of similar features in independent evolutionary lineages is
known as:
A. Homology
B. Adaptive radiation
C. Divergent evolution
D. Convergent evolution
Answer: D
Rationale: Convergent evolution is the process whereby organisms not closely related
independently evolve similar traits as a result of having to adapt to similar environments
or ecological niches.
8. In the context of life history theory, what is ‘senescence’?
A. The ability to reproduce multiple times
B. The period of rapid growth after birth
C. The decline in physiological function with age
D. The mechanism of cell division
Answer: C
1. Which mode of natural selection favors individuals at both extremes of a
phenotypic range over those with intermediate phenotypes?
A. Disruptive selection
B. Stabilizing selection
C. Directional selection
D. Balancing selection
Answer: A
Rationale: Disruptive selection (or diversifying selection) occurs when environmental
conditions favor individuals at both extremes of a phenotypic range over individuals with
intermediate phenotypes.
2. In a population of 1000 individuals, if the frequency of the recessive allele ‘a’
is 0.3, what is the expected number of homozygous dominant individuals under
Hardy-Weinberg equilibrium?
A. 420
B. 90
C. 700
D. 490
Answer: D
Rationale: If q = 0.3, then p = 0.7. The frequency of homozygous dominant individuals
(p^2) is 0.7 * 0.7 = 0.49. For 1000 individuals, 0.49 * 1000 = 490.
,3. Which of the following is the primary source of new genetic variation in a
population?
A. Genetic drift
B. Natural selection
C. Gene flow
D. Mutation
Answer: D
Rationale: Mutation is the ultimate source of all genetic variation, providing the raw
material upon which other evolutionary forces like selection and drift can act.
4. Genetic drift has the most significant impact on which type of population?
A. Large populations with high gene flow
B. Migratory populations
C. Populations in Hardy-Weinberg equilibrium
D. Small, isolated populations
Answer: D
Rationale: Genetic drift refers to random fluctuations in allele frequencies. These random
effects are much more pronounced and likely to lead to fixation or loss of alleles in small
populations.
5. Which phylogenetic term describes a group that includes a common ancestor
and all of its descendants?
A. Paraphyletic
B. Polyphyletic
C. Outgroup
D. Monophyletic
Answer: D
Rationale: A monophyletic group, or clade, consists of an ancestral species and all its
descendants, distinguished by shared derived characters (synapomorphies).
, 6. What is the ‘Biological Species Concept’ primarily based on?
A. Reproductive isolation
B. Ecological niche
C. Morphological similarity
D. Phylogenetic lineage
Answer: A
Rationale: The Biological Species Concept defines a species as a group of populations
whose members have the potential to interbreed in nature and produce viable, fertile
offspring.
7. The evolution of similar features in independent evolutionary lineages is
known as:
A. Homology
B. Adaptive radiation
C. Divergent evolution
D. Convergent evolution
Answer: D
Rationale: Convergent evolution is the process whereby organisms not closely related
independently evolve similar traits as a result of having to adapt to similar environments
or ecological niches.
8. In the context of life history theory, what is ‘senescence’?
A. The ability to reproduce multiple times
B. The period of rapid growth after birth
C. The decline in physiological function with age
D. The mechanism of cell division
Answer: C
