1.
Natural selection is based on all of the following except
A. 
Genetic variation exists within populations.
B. 
The best-adapted individuals tend to leave the most offspring.
C. 
Only a fraction of the offspring produced by an individual may survive.
D. 
Populations tend to produce more individuals than the environment can support.
E. 
Individuals adapt to their environments and, thereby, evolve.
2.
Ichthyosaurs were aquatic dinosaurs. Fossils show us that they had dorsal fins and tails, as do fish, even though their closest relatives were terrestrial reptiles that had neither dorsal fins nor aquatic tails. The dorsal fins and tails of ichthyosaurs and fish are
A. 
B. 
Examples of convergent evolution.
C. 
Adaptations to a common environment.
D. 
E. 
3.
Which of the following pairs of structures is least likely to be homologous?
A. 
The wings of a bat and the arms of a human
B. 
The hemoglobin of a baboon and that of a gorilla
C. 
The mitochondria of a plant and those of an animal
D. 
The wings of a bird and those of an insect
E. 
The brain of a cat and that of a dog
4.
A trend toward the decrease in the size of plants on the slopes of mountains as altitudes increase is an example of
A. 
B. 
C. 
D. 
E. 
5.
In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of the allele a is 0.4. What is the percentage of the population that is homozygous for this allele?
A. 
B. 
C. 
D. 
E. 
6.
In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of allele a is 0.1. What is the percentage of the population that is heterozygous for this allele?
A. 
B. 
C. 
D. 
E. 
7.
In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of allele a is 0.2. What is the frequency of individuals with Aa genotype?
A. 
B. 
C. 
D. 
E. 
Genotype frequency cannot be determined from the information provided.
8.
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. What is the frequency of the B allele?
A. 
B. 
C. 
D. 
E. 
9.
In peas, a gene controls flower color such that R = purple and r = white. In an isolated pea patch, there are 36 purple-flowering plants and 64 white-flowering plants. Assuming Hardy-Weinberg equilibrium, what is the value of q for this population?
A. 
B. 
C. 
D. 
E. 
10.
When we say that an individual organism has a greater fitness than another individual, we specifically mean that the organism
A. 
Lives longer than others of its species.
B. 
Competes for resources more successfully than others of its species.
C. 
Mates more frequently than others of its species.
D. 
Utilizes resources more efficiently than other species occupying similar niches.
E. 
Leaves more viable offspring than others of its species.
11.
Fossil evidence indicates that horses have gradually increased in size over geologic time. Which of the following terms best describes this?
A. 
B. 
C. 
D. 
Diversifying (disruptive) selection
E. 
12.
The recessive allele that causes phenylketonuria (PKU) is harmful, except when an infant's diet lacks the amino acid, phenylalanine. What maintains the presence of this harmful allele in a population's gene pool?
A. 
B. 
C. 
D. 
E. 
13.
In seedcracker finches from Cameroon, small- and large-billed birds specialize in cracking soft and hard seeds, respectively. If long-term climatic change resulted in all seeds becoming hard, what type of selection would then operate on the finch population?
A. 
Diversifying (disruptive) selection
B. 
C. 
D. 
E. 
No selection would operate because the population is in Hardy-Weinberg equilibrium.
14.
Male satin bowerbirds adorn structures that they build, called "bowers," with parrot feathers, flowers, and other bizarre ornaments in order to attract females. Females inspect the bowers and, if suitably impressed, allow males to mate with them. The evolution of this male behavior is due to
A. 
Frequency-dependent selection.
B. 
C. 
D. 
E. 
15.
When imbalances occur in the sex ratio of sexual species that have two sexes (i.e. other than a 50:50 ratio), the members of the minority sex often receive a greater proportion of care and resources from parents than do the offspring of the majority sex. This is most clearly an example of
A. 
B. 
Diversifying (disruptive) selection.
C. 
D. 
E. 
Frequency-dependent selection.
16.
Sparrows with average-sized wings survive severe storms better than those with longer or shorter wings, illustrating
A. 
B. 
C. 
Frequency-dependent selection.
D. 
E. 
17.
Several closely related frog species of the genus Rana are found in the forests of the southeastern United States. The species boundaries are maintained by reproductive barriers. Males of one species sing only when its predators are absent; males of another species sing only when its predators are present. Which type of reproductive barrier does this represent?
A. 
B. 
C. 
D. 
E. 
18.
Several closely related frog species of the genus Rana are found in the forests of the southeastern United States. The species boundaries are maintained by reproductive barriers. One species lives only in tree holes; another species lives only in streams. Which type of reproductive barrier does this represent?
A. 
B. 
C. 
D. 
E. 
19.
Several closely related frog species of the genus Rana are found in the forests of the southeastern United States. The species boundaries are maintained by reproductive barriers. One species mates at the season when daylight is increasing from 13 hours to 13 hours, 15 minutes; another species mates at the season when daylight is increasing from 14 hours to 14 hours, 15 minutes. Which type of reproductive barrier does this represent?
A. 
B. 
C. 
D. 
E. 
20.
Several closely related frog species of the genus Rana are found in the forests of the southeastern United States. The species boundaries are maintained by reproductive barriers. Males of one species are too small to perform amplexus with females of all other species. Which type of reproductive barrier does this represent?
A. 
B. 
C. 
D. 
E. 
21.
Two species of frogs belonging to the same genus occasionally mate, but the offspring fail to develop and hatch. What is the mechanism for keeping the two frog species separate?
A. 
B. 
C. 
D. 
E. 
22.
A defining characteristic of allopatric speciation is
A. 
The appearance of new species in the midst of old ones.
B. 
Asexually reproducing populations.
C. 
D. 
E. 
23.
Beetle pollinators of a particular plant are attracted to its flowers' bright orange color. The beetles not only pollinate the flowers, but they mate while inside of the flowers. A mutant version of the plant with red flowers becomes more common with the passage of time. A particular variant of the beetle prefers the red flowers to the orange flowers. Over time, these two beetle variants diverge from each other to such an extent that interbreeding is no longer possible. Which term best describes this scenario?
A. 
B. 
C. 
D. 
E. 
24.
Males of different species of the fruit fly Drosophila that live in the same parts of the Hawaiian islands have different elaborate courtship rituals that involve fighting other males and stylized movements that attract females. What type of reproductive isolation does this represent?
A. 
B. 
C. 
D. 
E. 
25.
A taxon, all of whose members have the same common ancestor, is