BIOL286 BIOL 286 EXAM 1 – 27 MCQs
PURDUE UNIVERSITY
Exam Part III: There are 25 multiple-choice questions (plus bonus). Select the best answer to each and
fill in the corresponding letter on your scahtron. Each question is worth three points.
1. In which of the following do microevolutionary changes occur?
A. gene
B. biomolecule
C. community
D. population
E. individual
2. Which of the following would NOT be a factor that influences how rapidly organisms may evolve?
A. The size of the population.
B. The number of haplotypes within the population.
C. The rates of environmental change organisms experience.
D. The generation time of the population.
E. The amount of genetic variation within the species.
3. Horizontal gene transfer
A. may allow organisms to acquire genes that can contribute to increased fitness.
B. is most common among prokaryotes.
C. may occur between prokaryotes and eukaryotes.
D. All of the above are correct.
E. Only A and B are correct.
4. The figure below shows the average flower guide size as a function of corolla size preferred by
different pollinators of the monkey flower, Mimulus luteus, in Chile. This is an example of
A. directional selection favoring large corolla size.
B. directional selection favoring large guide size.
C. directional selection favoring small corolla and large guide size.
D. disruptive selection.
E. stabilizing selection
5. Individuals affected by Huntington’s chorea have high numbers (e.g. 40+) of a CAG trinucleotide
, repeat in their huntingtin protein gene. This is an example of
A. directional selection
B. mutation
C. recombination
D. horizontal gene transfer
E. natural selection
6. When an island population of great tits, Parus major, was first sampled, researchers found between
8 and 17 eggs per nest (clutch size), with an average of 12. When the bird population was sampled
three years later, researchers found between 9 and 15 eggs per nest, with an average of 12. This is
an example of:
A. artificial selection.
B. directional selection favoring large clutch size.
C. directional selection favoring small clutch size.
D. disruptive selection.
E. stabilizing selection.
7. Which of the following correctly describes phenotypic plasticity?
A. Different genotypes are found in different frequencies in different environments.
B. A phenotypically plastic population contains less genetic variation than a population that lacks
phenotypic plasticity for the same trait.
C. The degree of phenotypic plasticity in a population may be estimated by looking at reaction
norms.
D. All of the above are correct.
E. Only B and C are correct.
8. If a population has a genetic locus with two alleles, what has occurred when one of the alleles goes
to fixation?
A. one of the alleles was eliminated from the population.
B. a new allele was introduced into the population.
C. one of the alleles occurs at a frequency of 1.0.
D. Both A and B are correct.
E. Both A and C are correct.
9. Which of the following is NOT an assumption of the Hardy-Weinberg Theorem?
A. no emigration
B. genetic drift
C. no immigration
D. no mutation
E. no natural selection
(For questions 10 and 11) The mean number of bristles on the abdomens of a population of Drosophila
pseudoobscura was 32. The mean number of bristles of D. pseudoobscura who survived to breed was
36. (Recall that R = h2S).
10. What is the selection differential on bristle number?
A. 36 bristles
PURDUE UNIVERSITY
Exam Part III: There are 25 multiple-choice questions (plus bonus). Select the best answer to each and
fill in the corresponding letter on your scahtron. Each question is worth three points.
1. In which of the following do microevolutionary changes occur?
A. gene
B. biomolecule
C. community
D. population
E. individual
2. Which of the following would NOT be a factor that influences how rapidly organisms may evolve?
A. The size of the population.
B. The number of haplotypes within the population.
C. The rates of environmental change organisms experience.
D. The generation time of the population.
E. The amount of genetic variation within the species.
3. Horizontal gene transfer
A. may allow organisms to acquire genes that can contribute to increased fitness.
B. is most common among prokaryotes.
C. may occur between prokaryotes and eukaryotes.
D. All of the above are correct.
E. Only A and B are correct.
4. The figure below shows the average flower guide size as a function of corolla size preferred by
different pollinators of the monkey flower, Mimulus luteus, in Chile. This is an example of
A. directional selection favoring large corolla size.
B. directional selection favoring large guide size.
C. directional selection favoring small corolla and large guide size.
D. disruptive selection.
E. stabilizing selection
5. Individuals affected by Huntington’s chorea have high numbers (e.g. 40+) of a CAG trinucleotide
, repeat in their huntingtin protein gene. This is an example of
A. directional selection
B. mutation
C. recombination
D. horizontal gene transfer
E. natural selection
6. When an island population of great tits, Parus major, was first sampled, researchers found between
8 and 17 eggs per nest (clutch size), with an average of 12. When the bird population was sampled
three years later, researchers found between 9 and 15 eggs per nest, with an average of 12. This is
an example of:
A. artificial selection.
B. directional selection favoring large clutch size.
C. directional selection favoring small clutch size.
D. disruptive selection.
E. stabilizing selection.
7. Which of the following correctly describes phenotypic plasticity?
A. Different genotypes are found in different frequencies in different environments.
B. A phenotypically plastic population contains less genetic variation than a population that lacks
phenotypic plasticity for the same trait.
C. The degree of phenotypic plasticity in a population may be estimated by looking at reaction
norms.
D. All of the above are correct.
E. Only B and C are correct.
8. If a population has a genetic locus with two alleles, what has occurred when one of the alleles goes
to fixation?
A. one of the alleles was eliminated from the population.
B. a new allele was introduced into the population.
C. one of the alleles occurs at a frequency of 1.0.
D. Both A and B are correct.
E. Both A and C are correct.
9. Which of the following is NOT an assumption of the Hardy-Weinberg Theorem?
A. no emigration
B. genetic drift
C. no immigration
D. no mutation
E. no natural selection
(For questions 10 and 11) The mean number of bristles on the abdomens of a population of Drosophila
pseudoobscura was 32. The mean number of bristles of D. pseudoobscura who survived to breed was
36. (Recall that R = h2S).
10. What is the selection differential on bristle number?
A. 36 bristles
