ASU BIO 182 EXAM 2 QUESTIONS WITH COMPLETE
SOLUTIONS 2026/2027
Arizona State University | General Biology II
Aligned with the ASU BIO 182 Course Syllabus and the AAAS Vision and Change Core Concepts (2026/2027
Edition)
Total Questions 100
Sections 8
Cognitive Mix 25% Recall / 50% Application / 25% Analysis
Question Type Multiple Choice (4 options, one correct)
Special Features 15 scenario-based evolution items, 10 Hardy-Weinberg calculations, 10 phylogenetic tree interpretation items
Section 1: Evolution & Natural Selection
[Application]
*Q1:* A population of beetles shows color variation ranging from light green to dark brown. After 10
generations of bird predation that preferentially removes green beetles, 90% of the population is brown.
This shift in phenotype frequency is best explained by:
A. Genetic drift caused by random chance events
B. Directional natural selection favoring the brown extreme *[CORRECT]*
C. Stabilizing selection favoring intermediate coloration
D. The founder effect from a small colonizing group
Correct Answer: B
Rationale: Directional selection occurs when natural selection favors one extreme phenotype, shifting the
population's trait distribution in a single direction over generations (Vision and Change Core Concept: Evolution).
The brown beetles had a survival advantage, so the trait frequency shifted toward brown. Stabilizing selection
favors the intermediate, the founder effect is a form of genetic drift involving a small colonizing population, and
random genetic drift is not selective.
,ASU BIO 182 EXAM 2 - Questions with Complete Solutions (2026/2027) Page 2
[Application]
*Q2:* Peter and Rosemary Grant documented that during severe drought on the Galapagos, medium
ground finches with deeper, stronger beaks survived at higher rates because they could crack the large,
hard seeds that remained. This is an example of:
A. Disruptive selection favoring both extremes
B. Stabilizing selection favoring the average beak depth
C. Directional selection favoring deeper beaks *[CORRECT]*
D. Sexual selection driven by female mate choice
Correct Answer: C
Rationale: The Grant finch studies are a textbook case of directional selection: during drought, the average beak
depth shifted upward because birds with deeper beaks could exploit hard seeds that softer-beaked birds could not
(ASU BIO 182 evolution unit; Vision and Change Core Concept: Evolution). Disruptive selection favors both
extremes simultaneously; stabilizing selection favors the intermediate; sexual selection involves mating success, not
survival.
[Recall]
*Q3:* Which of the following is NOT one of Darwin's observations and inferences underlying descent with
modification?
A. Individuals in a population vary in their heritable traits
B. Species produce more offspring than the environment can support
C. Traits acquired during an organism's lifetime are inherited by offspring *[CORRECT]*
D. Individuals with heritable traits best suited to the environment produce more offspring
Correct Answer: C
Rationale: Darwin's descent with modification rests on the observations that populations exhibit heritable
variation, that more offspring are produced than can survive, and that individuals with favorable heritable traits
survive and reproduce at higher rates (ASU BIO 182 evolution unit; Vision and Change Core Concept: Evolution).
The inheritance of acquired characteristics was Lamarck's erroneous hypothesis, not Darwin's, and was rejected
once the basis of heredity was understood.
Aligned with ASU BIO 182 Syllabus and AAAS Vision and Change Core Concepts
,ASU BIO 182 EXAM 2 - Questions with Complete Solutions (2026/2027) Page 3
[Analysis]
*Q4:* Cave-dwelling populations of the fish Astyanax mexicanus have nonfunctional, reduced eyes
covered by skin, while surface-dwelling populations of the same species have fully functional eyes. The
remnant eyes in cavefish are best described as:
A. Analogous structures that evolved by convergence
B. Vestigial structures that no longer serve their original function *[CORRECT]*
C. Homologous structures shared with surface fish by common ancestry
D. Exaptations co-opted for a new sensory function
Correct Answer: B
Rationale: Vestigial structures are remnants of features that served important functions in an organism's ancestors
but have reduced or no function in descendants (ASU BIO 182 evolution unit; Vision and Change Core Concept:
Evolution). In lightless caves, eye maintenance is costly and selection relaxed on eye function, so eyes degenerated.
Homologous structures share ancestry and still function; analogous structures perform similar functions but arose
independently; exaptations are traits co-opted for new uses.
[Application]
*Q5:* The wings of a butterfly (an insect) and the wings of a bird both enable flight, but they develop from
completely different embryonic structures and evolved independently. These wings are best described as:
A. Homologous structures sharing common ancestry
B. Analogous structures arising by convergent evolution *[CORRECT]*
C. Vestigial structures with reduced function
D. Homologous structures undergoing divergent evolution
Correct Answer: B
Rationale: Analogous structures perform similar functions but arose independently in different lineages and are
not derived from a common ancestral structure, a hallmark of convergent evolution (ASU BIO 182 evolution unit;
Vision and Change Core Concept: Evolution). Insect and bird wings share the function of flight but evolved from
different precursors (insect wing outgrowths vs. vertebrate forelimb). Homologous structures share common
ancestry but may perform different functions.
Aligned with ASU BIO 182 Syllabus and AAAS Vision and Change Core Concepts
, ASU BIO 182 EXAM 2 - Questions with Complete Solutions (2026/2027) Page 4
[Recall]
*Q6:* The forelimbs of humans, whales, bats, and cats all contain the same basic bone arrangement
(humerus, radius, ulna, carpals, metacarpals, phalanges), despite performing different functions. This is
best described as evidence of:
A. Convergent evolution producing analogous structures
B. Adaptive radiation producing analogous traits
C. Homologous structures inherited from a common ancestor *[CORRECT]*
D. Vestigial structures with reduced function
Correct Answer: C
Rationale: Homologous structures are anatomical similarities resulting from common ancestry, even when the
structures perform different functions in descendants (ASU BIO 182 evolution unit; Vision and Change Core
Concept: Evolution). The shared bone arrangement of mammalian forelimbs is a classic example, supporting
Darwin's descent with modification. Analogous structures arise by convergence; vestigial structures are reduced
remnants; adaptive radiation produces diversity from a common ancestor but does not imply analogous structures.
[Application]
*Q7:* Male peacocks have elaborate trains (tail feathers) that impose energetic costs and increase
predation risk, yet females preferentially mate with males displaying the most elaborate trains. This is an
example of:
A. Intrasexual selection driven by male-male combat
B. Intersexual selection driven by female mate choice *[CORRECT]*
C. Directional natural selection for survival
D. Stabilizing natural selection on tail length
Correct Answer: B
Rationale: Intersexual selection (mate choice) occurs when individuals of one sex (usually females) are choosy and
select mates based on particular traits, driving the evolution of elaborate secondary sexual characteristics (ASU
BIO 182 evolution unit). The peacock's train is the classic textbook example. Intrasexual selection involves direct
competition among members of one sex for mates; natural selection acts on survival, not mating success alone.
[Recall]
*Q8:* Which statement best distinguishes artificial selection from natural selection?
A. Artificial selection proceeds faster than natural selection in all cases
B. Artificial selection is imposed by humans choosing which traits to breed, while natural selection is
imposed by the environment *[CORRECT]*
C. Artificial selection produces less heritable variation than natural selection
D. Artificial selection operates only in plants, while natural selection operates only in animals
Correct Answer: B
Rationale: Artificial selection involves humans selectively breeding organisms with desired traits, while natural
selection is the differential survival and reproduction of individuals based on heritable variation in nature (ASU
BIO 182 evolution unit; Vision and Change Core Concept: Evolution). Darwin used artificial selection (pigeon
breeding, crop domestication) as an accessible analogy for natural selection. The key distinction is the selective
agent, not the speed or the taxonomic scope.
Aligned with ASU BIO 182 Syllabus and AAAS Vision and Change Core Concepts
SOLUTIONS 2026/2027
Arizona State University | General Biology II
Aligned with the ASU BIO 182 Course Syllabus and the AAAS Vision and Change Core Concepts (2026/2027
Edition)
Total Questions 100
Sections 8
Cognitive Mix 25% Recall / 50% Application / 25% Analysis
Question Type Multiple Choice (4 options, one correct)
Special Features 15 scenario-based evolution items, 10 Hardy-Weinberg calculations, 10 phylogenetic tree interpretation items
Section 1: Evolution & Natural Selection
[Application]
*Q1:* A population of beetles shows color variation ranging from light green to dark brown. After 10
generations of bird predation that preferentially removes green beetles, 90% of the population is brown.
This shift in phenotype frequency is best explained by:
A. Genetic drift caused by random chance events
B. Directional natural selection favoring the brown extreme *[CORRECT]*
C. Stabilizing selection favoring intermediate coloration
D. The founder effect from a small colonizing group
Correct Answer: B
Rationale: Directional selection occurs when natural selection favors one extreme phenotype, shifting the
population's trait distribution in a single direction over generations (Vision and Change Core Concept: Evolution).
The brown beetles had a survival advantage, so the trait frequency shifted toward brown. Stabilizing selection
favors the intermediate, the founder effect is a form of genetic drift involving a small colonizing population, and
random genetic drift is not selective.
,ASU BIO 182 EXAM 2 - Questions with Complete Solutions (2026/2027) Page 2
[Application]
*Q2:* Peter and Rosemary Grant documented that during severe drought on the Galapagos, medium
ground finches with deeper, stronger beaks survived at higher rates because they could crack the large,
hard seeds that remained. This is an example of:
A. Disruptive selection favoring both extremes
B. Stabilizing selection favoring the average beak depth
C. Directional selection favoring deeper beaks *[CORRECT]*
D. Sexual selection driven by female mate choice
Correct Answer: C
Rationale: The Grant finch studies are a textbook case of directional selection: during drought, the average beak
depth shifted upward because birds with deeper beaks could exploit hard seeds that softer-beaked birds could not
(ASU BIO 182 evolution unit; Vision and Change Core Concept: Evolution). Disruptive selection favors both
extremes simultaneously; stabilizing selection favors the intermediate; sexual selection involves mating success, not
survival.
[Recall]
*Q3:* Which of the following is NOT one of Darwin's observations and inferences underlying descent with
modification?
A. Individuals in a population vary in their heritable traits
B. Species produce more offspring than the environment can support
C. Traits acquired during an organism's lifetime are inherited by offspring *[CORRECT]*
D. Individuals with heritable traits best suited to the environment produce more offspring
Correct Answer: C
Rationale: Darwin's descent with modification rests on the observations that populations exhibit heritable
variation, that more offspring are produced than can survive, and that individuals with favorable heritable traits
survive and reproduce at higher rates (ASU BIO 182 evolution unit; Vision and Change Core Concept: Evolution).
The inheritance of acquired characteristics was Lamarck's erroneous hypothesis, not Darwin's, and was rejected
once the basis of heredity was understood.
Aligned with ASU BIO 182 Syllabus and AAAS Vision and Change Core Concepts
,ASU BIO 182 EXAM 2 - Questions with Complete Solutions (2026/2027) Page 3
[Analysis]
*Q4:* Cave-dwelling populations of the fish Astyanax mexicanus have nonfunctional, reduced eyes
covered by skin, while surface-dwelling populations of the same species have fully functional eyes. The
remnant eyes in cavefish are best described as:
A. Analogous structures that evolved by convergence
B. Vestigial structures that no longer serve their original function *[CORRECT]*
C. Homologous structures shared with surface fish by common ancestry
D. Exaptations co-opted for a new sensory function
Correct Answer: B
Rationale: Vestigial structures are remnants of features that served important functions in an organism's ancestors
but have reduced or no function in descendants (ASU BIO 182 evolution unit; Vision and Change Core Concept:
Evolution). In lightless caves, eye maintenance is costly and selection relaxed on eye function, so eyes degenerated.
Homologous structures share ancestry and still function; analogous structures perform similar functions but arose
independently; exaptations are traits co-opted for new uses.
[Application]
*Q5:* The wings of a butterfly (an insect) and the wings of a bird both enable flight, but they develop from
completely different embryonic structures and evolved independently. These wings are best described as:
A. Homologous structures sharing common ancestry
B. Analogous structures arising by convergent evolution *[CORRECT]*
C. Vestigial structures with reduced function
D. Homologous structures undergoing divergent evolution
Correct Answer: B
Rationale: Analogous structures perform similar functions but arose independently in different lineages and are
not derived from a common ancestral structure, a hallmark of convergent evolution (ASU BIO 182 evolution unit;
Vision and Change Core Concept: Evolution). Insect and bird wings share the function of flight but evolved from
different precursors (insect wing outgrowths vs. vertebrate forelimb). Homologous structures share common
ancestry but may perform different functions.
Aligned with ASU BIO 182 Syllabus and AAAS Vision and Change Core Concepts
, ASU BIO 182 EXAM 2 - Questions with Complete Solutions (2026/2027) Page 4
[Recall]
*Q6:* The forelimbs of humans, whales, bats, and cats all contain the same basic bone arrangement
(humerus, radius, ulna, carpals, metacarpals, phalanges), despite performing different functions. This is
best described as evidence of:
A. Convergent evolution producing analogous structures
B. Adaptive radiation producing analogous traits
C. Homologous structures inherited from a common ancestor *[CORRECT]*
D. Vestigial structures with reduced function
Correct Answer: C
Rationale: Homologous structures are anatomical similarities resulting from common ancestry, even when the
structures perform different functions in descendants (ASU BIO 182 evolution unit; Vision and Change Core
Concept: Evolution). The shared bone arrangement of mammalian forelimbs is a classic example, supporting
Darwin's descent with modification. Analogous structures arise by convergence; vestigial structures are reduced
remnants; adaptive radiation produces diversity from a common ancestor but does not imply analogous structures.
[Application]
*Q7:* Male peacocks have elaborate trains (tail feathers) that impose energetic costs and increase
predation risk, yet females preferentially mate with males displaying the most elaborate trains. This is an
example of:
A. Intrasexual selection driven by male-male combat
B. Intersexual selection driven by female mate choice *[CORRECT]*
C. Directional natural selection for survival
D. Stabilizing natural selection on tail length
Correct Answer: B
Rationale: Intersexual selection (mate choice) occurs when individuals of one sex (usually females) are choosy and
select mates based on particular traits, driving the evolution of elaborate secondary sexual characteristics (ASU
BIO 182 evolution unit). The peacock's train is the classic textbook example. Intrasexual selection involves direct
competition among members of one sex for mates; natural selection acts on survival, not mating success alone.
[Recall]
*Q8:* Which statement best distinguishes artificial selection from natural selection?
A. Artificial selection proceeds faster than natural selection in all cases
B. Artificial selection is imposed by humans choosing which traits to breed, while natural selection is
imposed by the environment *[CORRECT]*
C. Artificial selection produces less heritable variation than natural selection
D. Artificial selection operates only in plants, while natural selection operates only in animals
Correct Answer: B
Rationale: Artificial selection involves humans selectively breeding organisms with desired traits, while natural
selection is the differential survival and reproduction of individuals based on heritable variation in nature (ASU
BIO 182 evolution unit; Vision and Change Core Concept: Evolution). Darwin used artificial selection (pigeon
breeding, crop domestication) as an accessible analogy for natural selection. The key distinction is the selective
agent, not the speed or the taxonomic scope.
Aligned with ASU BIO 182 Syllabus and AAAS Vision and Change Core Concepts
