BIOD 102 Biology II Module 1 Exam Portage
Learning ACTUAL EXAM 2026/2027 |
BIOD 102 Biology II | Verified Q&A | Pass
Guaranteed - A+ Graded
Section A: Multiple Choice (Questions 1–35)
Q1: A population of beetles shows variation in body color. Over several generations, the darker beetles
become more common because they are better camouflaged from predators. This is an example of:
A. Genetic drift
B. Natural selection. [CORRECT]
C. Gene flow
D. Mutation pressure
Correct Answer: B
Rationale: Natural selection is the mechanism by which individuals with heritable traits better suited to
their environment survive and reproduce at higher rates, leading to an increase in favorable alleles over
generations. The darker beetles' improved camouflage provides a survival advantage against predation,
which is the defining feature of directional selection in evolutionary biology.
Q2: Based on the phylogenetic tree where Taxon A and Taxon B share a more recent common ancestor
than either shares with Taxon C, which of the following statements is true?
A. Taxon A and Taxon B are sister taxa. [CORRECT]
B. Taxon C is more closely related to Taxon A than to Taxon B
C. Taxon A evolved from Taxon C
D. Taxon B is the outgroup for Taxa A and C
Correct Answer: A
Rationale: Sister taxa are defined as two lineages that diverged from the same immediate common
ancestor. In a phylogenetic tree, the branching pattern reveals evolutionary relationships, and the node
,connecting Taxon A and Taxon B represents their most recent common ancestor, making them sister
taxa regardless of how similar they appear phenotypically.
Q3: Which of the following is NOT a requirement for Hardy-Weinberg equilibrium?
A. No mutations
B. Random mating
C. Natural selection occurring. [CORRECT]
D. Large population size
Correct Answer: C
Rationale: Hardy-Weinberg equilibrium describes a theoretical population in which allele and genotype
frequencies remain constant from generation to generation. One of its five core assumptions is the
absence of natural selection; if natural selection is actively occurring, allele frequencies will change
directionally, violating equilibrium conditions.
Q4: The forelimbs of humans, whales, bats, and cats contain the same bones (humerus, radius, ulna,
carpals, metacarpals, phalanges) arranged in similar patterns, despite serving different functions. These
structures are best described as:
A. Analogous structures
B. Homologous structures. [CORRECT]
C. Vestigial structures
D. Convergent structures
Correct Answer: B
Rationale: Homologous structures share a common evolutionary origin and underlying anatomical plan
due to inheritance from a common ancestor, even when adapted for different functions. The
pentadactyl limb pattern across these diverse mammals is classic evidence of common ancestry and
divergent evolution.
Q5: A biologist discovers two populations of frogs that were once connected but are now separated by a
mountain range. Over time, the populations have diverged genetically and can no longer interbreed.
This is an example of:
A. Sympatric speciation
B. Allopatric speciation. [CORRECT]
C. Parapatric speciation
D. Polyploidy
, Correct Answer: B
Rationale: Allopatric speciation occurs when a population is divided by a geographic barrier, interrupting
gene flow between the separated groups. Over evolutionary time, genetic divergence accumulates due
to mutation, natural selection, and genetic drift in isolation, eventually leading to reproductive isolation
and the formation of distinct species.
Q6: In a population of 1,000 individuals, the frequency of the recessive allele (q) for a particular gene is
0.3. According to Hardy-Weinberg equilibrium, how many individuals are expected to be heterozygous?
A. 210
B. 420. [CORRECT]
C. 490
D. 90
Correct Answer: B
Rationale: Under Hardy-Weinberg equilibrium, p + q = 1, so p = 0.7. The heterozygote frequency is
represented by 2pq, which equals 2 × 0.7 × 0.3 = 0.42. Multiplying 0.42 by the population size of 1,000
yields 420 expected heterozygous individuals, demonstrating the mathematical prediction of genotype
frequencies in an equilibrium population.
Q7: Which of the following provides the strongest evidence that whales evolved from terrestrial
mammals?
A. Whales have streamlined bodies for swimming
B. Fossil evidence shows transitional forms with hind limb bones and teeth resembling those of ancient
land mammals. [CORRECT]
C. Whales breathe air through lungs
D. Whales nurse their young with milk
Correct Answer: B
Rationale: Transitional fossils provide direct observable evidence of evolutionary change over time.
Fossils such as Pakicetus, Ambulocetus, and Rodhocetus document the gradual anatomical
transformation from four-legged terrestrial ancestors to fully aquatic whales, including the reduction of
hind limbs and modification of teeth—serving as compelling proof of evolutionary lineage.
Q8: A cladogram groups organisms based on:
A. Overall physical similarity
B. Shared derived characteristics (synapomorphies). [CORRECT]
Learning ACTUAL EXAM 2026/2027 |
BIOD 102 Biology II | Verified Q&A | Pass
Guaranteed - A+ Graded
Section A: Multiple Choice (Questions 1–35)
Q1: A population of beetles shows variation in body color. Over several generations, the darker beetles
become more common because they are better camouflaged from predators. This is an example of:
A. Genetic drift
B. Natural selection. [CORRECT]
C. Gene flow
D. Mutation pressure
Correct Answer: B
Rationale: Natural selection is the mechanism by which individuals with heritable traits better suited to
their environment survive and reproduce at higher rates, leading to an increase in favorable alleles over
generations. The darker beetles' improved camouflage provides a survival advantage against predation,
which is the defining feature of directional selection in evolutionary biology.
Q2: Based on the phylogenetic tree where Taxon A and Taxon B share a more recent common ancestor
than either shares with Taxon C, which of the following statements is true?
A. Taxon A and Taxon B are sister taxa. [CORRECT]
B. Taxon C is more closely related to Taxon A than to Taxon B
C. Taxon A evolved from Taxon C
D. Taxon B is the outgroup for Taxa A and C
Correct Answer: A
Rationale: Sister taxa are defined as two lineages that diverged from the same immediate common
ancestor. In a phylogenetic tree, the branching pattern reveals evolutionary relationships, and the node
,connecting Taxon A and Taxon B represents their most recent common ancestor, making them sister
taxa regardless of how similar they appear phenotypically.
Q3: Which of the following is NOT a requirement for Hardy-Weinberg equilibrium?
A. No mutations
B. Random mating
C. Natural selection occurring. [CORRECT]
D. Large population size
Correct Answer: C
Rationale: Hardy-Weinberg equilibrium describes a theoretical population in which allele and genotype
frequencies remain constant from generation to generation. One of its five core assumptions is the
absence of natural selection; if natural selection is actively occurring, allele frequencies will change
directionally, violating equilibrium conditions.
Q4: The forelimbs of humans, whales, bats, and cats contain the same bones (humerus, radius, ulna,
carpals, metacarpals, phalanges) arranged in similar patterns, despite serving different functions. These
structures are best described as:
A. Analogous structures
B. Homologous structures. [CORRECT]
C. Vestigial structures
D. Convergent structures
Correct Answer: B
Rationale: Homologous structures share a common evolutionary origin and underlying anatomical plan
due to inheritance from a common ancestor, even when adapted for different functions. The
pentadactyl limb pattern across these diverse mammals is classic evidence of common ancestry and
divergent evolution.
Q5: A biologist discovers two populations of frogs that were once connected but are now separated by a
mountain range. Over time, the populations have diverged genetically and can no longer interbreed.
This is an example of:
A. Sympatric speciation
B. Allopatric speciation. [CORRECT]
C. Parapatric speciation
D. Polyploidy
, Correct Answer: B
Rationale: Allopatric speciation occurs when a population is divided by a geographic barrier, interrupting
gene flow between the separated groups. Over evolutionary time, genetic divergence accumulates due
to mutation, natural selection, and genetic drift in isolation, eventually leading to reproductive isolation
and the formation of distinct species.
Q6: In a population of 1,000 individuals, the frequency of the recessive allele (q) for a particular gene is
0.3. According to Hardy-Weinberg equilibrium, how many individuals are expected to be heterozygous?
A. 210
B. 420. [CORRECT]
C. 490
D. 90
Correct Answer: B
Rationale: Under Hardy-Weinberg equilibrium, p + q = 1, so p = 0.7. The heterozygote frequency is
represented by 2pq, which equals 2 × 0.7 × 0.3 = 0.42. Multiplying 0.42 by the population size of 1,000
yields 420 expected heterozygous individuals, demonstrating the mathematical prediction of genotype
frequencies in an equilibrium population.
Q7: Which of the following provides the strongest evidence that whales evolved from terrestrial
mammals?
A. Whales have streamlined bodies for swimming
B. Fossil evidence shows transitional forms with hind limb bones and teeth resembling those of ancient
land mammals. [CORRECT]
C. Whales breathe air through lungs
D. Whales nurse their young with milk
Correct Answer: B
Rationale: Transitional fossils provide direct observable evidence of evolutionary change over time.
Fossils such as Pakicetus, Ambulocetus, and Rodhocetus document the gradual anatomical
transformation from four-legged terrestrial ancestors to fully aquatic whales, including the reduction of
hind limbs and modification of teeth—serving as compelling proof of evolutionary lineage.
Q8: A cladogram groups organisms based on:
A. Overall physical similarity
B. Shared derived characteristics (synapomorphies). [CORRECT]
