Honors Practice Problems
1. Evolution occurs at the level of
a. the individual genotype
b. the individual phenotype
c. environmentally based phenotypic variation
d. the population
2. What does natural selection act upon?
a. The gene pool of the species
b. The genotype
c. The phenotype
d. Multiple gene inheritance systems
3. Suppose a particular species of flowering plant that lives only one year can produce red, white,
or pink blossoms, depending on its genotype. Biologists studying a population of this species
count 300 red-flowering, 500 white-flowering, and 800 pink-flowering plants in a population.
When the population is censused the following year, 600 red-flowering, 900 white-flowering, and
1000 pink-flowering plants are observed. Which color has the highest fitness?
a. Red
b. White
c. Pink
4. The ability to taste the chemical PTC is determined in humans by a dominant allele T, with
tasters having the genotypes Tt or TT and nontasters having tt. If you discover that 36% of the
members of a population cannot taste PTC, then according to Hardy-Weinberg equation, the
frequency of the T allele should be
a. 0.4
b. 0.6
c. 0.64
d. 0.8
5. A gene in humans has two alleles, M and N, that code for different surface proteins in red
blood cells. If you know what the frequency of allele M is 0.2, according to the Hardy-Weinberg
equation, the frequency of the genotype MN in the population should be
a. 0.16
b. 0.32
c. 0.64
d. 0.8
6. If the frequency of allele b in a gene pool is 0.2, according to the Hardy-Weinberg equation,
the expected frequency of the genotype bbb in a triploid (3n) plant species would be
a. 0.008
b. 0.04
c. 0.08
d. 0.2
7. A small, isolated population would most likely be subject over time to
a. assortative mating
b. a founder effect
c. genetic drift
d. gene flow
8. Which definition of evolution would have been most foreign to Charles Darwin during his
lifetime?
a. change in gene frequency in gene pools
b. descent with modification
c. the gradual change of a population’s heritable traits over generations
d. populations becoming better adapted to their environments over the course of
generations
e. the appearance of new varieties and new species with the passage of time
9. All of the following criteria for maintaining Hardy-Weinberg equilibrium involving two
alleles except
a. the frequency of all genotypes must be equal
b. there should be no natural selection
c. matings must be random
d. populations must be large
e. gene flow from other populations must be zero
10. In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the
frequency of the allele a is 0.7. What is the percentage of the population that is homozygous for
this allele?
a. 3
b. 9
c. 30
d. 42
e. 49
11. In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the
frequency of the allele a is 0.7. What is the percentage of the population that is heterozygous for
this allele?
a. 3
b. 9
c. 21
d. 30
e. 42
In a hypothetical population of 1,000 people, tests of blood-type genes show that 160 have the
genotype AA, 480 have the genotype AB, and 360 have the genotype BB.
12. What is the frequency of the A allele?
a. 0.001
b. 0.002
c. 0.100
d. 0.400
e. 0.600
13. What is the frequency of the B allele?
a. 0.001
b. 0.002
c. 0.100
d. 0.400
e. 0.600
14. What percentage of the population has type O blood?
a. 0
b. 10
c. 24
d. 48
e. 60
15. Which factor is the most important in producing the variability that occurs in each generation
of humans?
a. mutation
b. sexual recombination
c. genetic drift
d. nonrandom mating
e. natural selection
16. The Darwinian fitness of an individual is measured by
a. the number of its offspring that survive to reproduce
b. the number of supergenes in the genotype
c. the number of mates it attracts
d. its physical strength
e. how long it lives
17. The following important concepts of population genetics are due to random events or chance
except
a. mutation
b. the bottleneck effect
c. the founder effect
d. natural selection
e. sexual recombination
18. If the frequency of a particular allele that is present in a small, isolated population of alpine
plants should change due to a landslide that leaves an even smaller remnant of surviving plants,
then what has occurred?
a. a bottleneck
b. genetic drift
c. microevolution
d. A and B only
e. A,B, and C
19. Which of the following statements best summarizes evolution as it is viewed today?
a. It is goal-directed
b. It represents the results of selection for acquired characteristics
c. It is synonymous with the process of gene flow
d. It is the descent of humans from the present-day great apes
e. It is the differential survival and reproduction of the most fit phenotypes
Choose among these options to answer the following questions. Each option may be used once,
more than once, or not at all.
A. random selection
B. directional selection
C. stabilizing selection
D. disruptive selection
E. sexual selection
20. An African butterfly species exists in two strikingly different color patterns
21. Brightly colored peacocks mate more frequently than do drab peacocks
22. Most Swiss starlings produce four to five eggs in each clutch
23. Fossil evidence indicates that horses have gradually increased in size over geologic time.
In a very large population, a quantitative trait has the following distribution pattern:
24. What is true of the trait whose frequency distribution in a large population appears above? It
has probably undergone
a. directional selection
b. stabilizing selection
c. disruptive selection
d. sexual selection
e. random selection
25. If the curve shifts to the left or to the right, there is no gene flow, and the population size
consequently increases over successive generations, then which of these is (are) probably
occurring?
1. immigration or emigration
2. directional selection
3. adaptation
4. genetic drift
5. disruptive selection
a.
b.
c.
d.
e.
1 only
4 only
2 and 3
4 and 5
1, 2, and 3
26. Which of the following is most likely to have been produced by sexual selection?
a. a male lion’s mane
b. bright colors of female flowers
c. the ability of desert animals to concentrate their urine
d. different sizes of male and female pinecones
e. camouflage coloration in animals
27. Male satin bowerbirds adorn structures that they build, called “bowers” with parrot feathers,
flowers, and other bizarre onaments in order to attract females. Females inspect the bowers and,
if suitably impressed, allow males to mate with them, after which they go off to nest by
themselves. The evolution of this behavior is best described as due to
a. survival of the fittest
b. artificial selection
c. sexual selection
d. natural selection
e. disruptive selection