ASU BIO 182 EXAM 2 QUESTIONS AND CORRECT
ANSWERS (VERIFIED ANSWERS) PLUS RATIONALES
Q &A 2026 |INSTANT DOWNLOAD PDF
1. Which of the following is a key characteristic of natural
selection?
A. Individuals evolve traits during their lifetime
B. Traits that increase fitness tend to become more common in
a population
C. Evolution always produces perfect organisms
D. Mutations are directed to benefit the organism
Rationale:
• A: Incorrect – Individuals do not evolve; populations
evolve.
• B: Correct – Natural selection favors traits that improve
reproductive success.
• C: Incorrect – Evolution does not guarantee perfection.
• D: Incorrect – Mutations occur randomly, not directed.
2. Which type of selection favors individuals with traits at
both extremes and selects against intermediate traits?
A. Stabilizing selection
B. Directional selection
,C. Disruptive selection
D. Sexual selection
Rationale:
• A: Incorrect – Stabilizing favors intermediates.
• B: Incorrect – Directional favors one extreme.
• C: Correct – Disruptive selection favors both extremes.
• D: Incorrect – Sexual selection favors traits that improve
mating success.
3. Genetic drift is more likely to have a significant effect in:
A. Large populations
B. Populations with high mutation rates
C. Small populations
D. Populations undergoing natural selection
Rationale:
• A: Incorrect – Drift is weaker in large populations.
• B: Incorrect – Mutation rate is not the main factor for drift.
• C: Correct – Drift has a stronger effect in small populations
due to random allele frequency changes.
• D: Incorrect – Natural selection is not random; drift is.
,4. Which of the following is a density-dependent factor
affecting population growth?
A. Natural disasters
B. Predation
C. Earthquakes
D. Volcanic eruptions
Rationale:
• A: Incorrect – Some natural disasters can be density-
dependent, but often density-independent.
• B: Correct – Predation depends on population density.
• C: Incorrect – Earthquakes are density-independent.
• D: Incorrect – Volcanic eruptions are density-independent.
5. Which of the following is a correct example of mutualism?
A. A tapeworm in a human intestine
B. Bees pollinating flowers while collecting nectar
C. A lion eating a zebra
D. Barnacles on a whale’s skin causing irritation
Rationale:
• A: Incorrect – Tapeworms harm hosts (parasitism).
• B: Correct – Both species benefit: bees get food, flowers
get pollinated.
• C: Incorrect – Predator-prey relationship.
, • D: Incorrect – Barnacles may harm the whale slightly; not
mutualism.
6. Which term describes the process by which unrelated
species evolve similar traits due to similar environments?
A. Divergent evolution
B. Convergent evolution
C. Coevolution
D. Adaptive radiation
Rationale:
• A: Incorrect – Divergent evolution produces differences
from a common ancestor.
• B: Correct – Convergent evolution produces similar traits in
unrelated species.
• C: Incorrect – Coevolution involves reciprocal evolutionary
changes.
• D: Incorrect – Adaptive radiation is rapid speciation from a
common ancestor.
7. Which of the following correctly lists the hierarchy of
ecological organization from smallest to largest?
A. Community → Population → Ecosystem → Organism
B. Organism → Population → Community → Ecosystem
ANSWERS (VERIFIED ANSWERS) PLUS RATIONALES
Q &A 2026 |INSTANT DOWNLOAD PDF
1. Which of the following is a key characteristic of natural
selection?
A. Individuals evolve traits during their lifetime
B. Traits that increase fitness tend to become more common in
a population
C. Evolution always produces perfect organisms
D. Mutations are directed to benefit the organism
Rationale:
• A: Incorrect – Individuals do not evolve; populations
evolve.
• B: Correct – Natural selection favors traits that improve
reproductive success.
• C: Incorrect – Evolution does not guarantee perfection.
• D: Incorrect – Mutations occur randomly, not directed.
2. Which type of selection favors individuals with traits at
both extremes and selects against intermediate traits?
A. Stabilizing selection
B. Directional selection
,C. Disruptive selection
D. Sexual selection
Rationale:
• A: Incorrect – Stabilizing favors intermediates.
• B: Incorrect – Directional favors one extreme.
• C: Correct – Disruptive selection favors both extremes.
• D: Incorrect – Sexual selection favors traits that improve
mating success.
3. Genetic drift is more likely to have a significant effect in:
A. Large populations
B. Populations with high mutation rates
C. Small populations
D. Populations undergoing natural selection
Rationale:
• A: Incorrect – Drift is weaker in large populations.
• B: Incorrect – Mutation rate is not the main factor for drift.
• C: Correct – Drift has a stronger effect in small populations
due to random allele frequency changes.
• D: Incorrect – Natural selection is not random; drift is.
,4. Which of the following is a density-dependent factor
affecting population growth?
A. Natural disasters
B. Predation
C. Earthquakes
D. Volcanic eruptions
Rationale:
• A: Incorrect – Some natural disasters can be density-
dependent, but often density-independent.
• B: Correct – Predation depends on population density.
• C: Incorrect – Earthquakes are density-independent.
• D: Incorrect – Volcanic eruptions are density-independent.
5. Which of the following is a correct example of mutualism?
A. A tapeworm in a human intestine
B. Bees pollinating flowers while collecting nectar
C. A lion eating a zebra
D. Barnacles on a whale’s skin causing irritation
Rationale:
• A: Incorrect – Tapeworms harm hosts (parasitism).
• B: Correct – Both species benefit: bees get food, flowers
get pollinated.
• C: Incorrect – Predator-prey relationship.
, • D: Incorrect – Barnacles may harm the whale slightly; not
mutualism.
6. Which term describes the process by which unrelated
species evolve similar traits due to similar environments?
A. Divergent evolution
B. Convergent evolution
C. Coevolution
D. Adaptive radiation
Rationale:
• A: Incorrect – Divergent evolution produces differences
from a common ancestor.
• B: Correct – Convergent evolution produces similar traits in
unrelated species.
• C: Incorrect – Coevolution involves reciprocal evolutionary
changes.
• D: Incorrect – Adaptive radiation is rapid speciation from a
common ancestor.
7. Which of the following correctly lists the hierarchy of
ecological organization from smallest to largest?
A. Community → Population → Ecosystem → Organism
B. Organism → Population → Community → Ecosystem
