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During a study session about evolution, one of your fellow students remarks, "The giraffe stretched its neck while reaching for higher leaves; its offspring inherited longer necks as a result." Which statement is most likely to be helpful in correcting this student's misconception?
a. Only favorable adaptations have survival value.
b. Characteristics acquired during an organism's life are generally not passed on through genes.
c. Disuse of an organ may lead to its eventual disappearance.
d. Overproduction of offspring leads to a struggle for survival.
e. Spontaneous mutations can result in the appearance of new traits. |
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Charles Darwin was the first person to propose
a. that evolution occurs.
b. a mechanism for how evolution occurs.
c. a way to use artificial selection as a means of domesticating plants and animals.
d. that the Earth is older than a few thousand years.
e. a mechanism for evolution that was supported by evidence. |
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In Darwin's thinking, the more closely related two different organisms are, the
a. less similar their DNA sequences are.
b. more recently they shared a common ancestor.
c. more similar they are in size.
d. less likely they are to have the same genes in common.
e. more similar their habitats are. |
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Natural selection is based on all of the following except
a. individuals who survive longer tend to leave more offspring than those who die young.
b. the best-adapted individuals tend to leave the most offspring.
c. genetic variation exists within populations.
d. individuals adapt to their environments and, thereby, evolve.
e. populations tend to produce more individuals than the environment can support. |
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Which statement about natural selection is most correct?
a. Natural selection is the sole means by which populations can evolve.
b. Adaptations beneficial in one habitat should generally be beneficial in all other habitats as well.
c. Well-adapted individuals leave more offspring, and thus contribute more to the next generation's gene pool, than do poorly adapted individuals.
d. Adaptations beneficial at one time should generally be beneficial during all other times as well.
e. Different species that occupy the same habitat will adapt to that habitat by undergoing the same genetic changes. |
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Given a population that contains genetic variation, what is the correct sequence of the following events, under the influence of natural selection?
1. Well-adapted individuals leave more offspring than do poorly adapted individuals.
2. A change occurs in the environment.
3. Genetic frequencies within the population change.
4. Poorly adapted individuals have decreased survivorship.
a. 4 → 2 → 1 → 3
b. 4 → 2 → 3 → 1
c. 2 → 4 → 3 → 1
d. 2 → 4 → 1 → 3
e. 4 → 1 → 2 → 3 |
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. A biologist studied a population of squirrels for 15 years. During that time, the population was never fewer than 30 squirrels and never more than 45. Her data showed that over half of the squirrels born did not survive to reproduce, because of competition for food and predation. In a single generation, 90% of the squirrels that were born lived to reproduce, and the population increased to 80. Which inference(s) about this population might be true?
a. The amount of available food may have increased.
b. The number of predators may have decreased.
c. The squirrels of subsequent generations should show greater levels of genetic variation than previous generations, because squirrels that would not have survived in the past will now survive.
d. A and B only
e. A, B, and C |
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Which of the following statements is an inference of natural selection?
a. Habitats do not generally have unlimited resources.
b. An individual organism undergoes evolution over the course of its lifetime.
c. Some of the variation that exists among individuals in a population is genetic.
d. Natural populations tend to reproduce to their full biological potential.
e. Subsequent generations of a population should have greater proportions of individuals that possess traits better suited for success. |
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Which of the following must exist in a population before natural selection can act upon that population?
a. Genetic variation among individuals
b. Variation among individuals caused by environmental factors
c. Sexual reproduction
d. B and C only
e. A, B, and C |
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How many separate species, both extant and extinct, are depicted in this tree?
a. 6
b. 4
c. 2
d. 3
e. 5 |
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According to this tree, what percent of the species seem to be extant (i.e., not extinct)?
a. 66%
b. 75%
c. 25%
d. 50%
e. 33% |
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Which of the five common ancestors, labeled V—Z, has given rise to the greatest number of species, both extant and extinct?
a. V
b. Y
c. Z
d. W
e. X |
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Which of the five common ancestors, labeled V—Z, has been least successful in terms of the percent of its derived species that are extant?
a. V
b. W
c. X
d. Z
e. Y |
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Which of the five common ancestors, labeled V—Z, has been most successful in terms of the percent of its derived species that are extant?
a. W
b. Y
c. Z
d. V
e. X |
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Evolutionary trees such as this are properly understood by scientists to be
a. laws.
b. dogmas.
c. hypotheses.
d. theories.
e. facts. |
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Which statement best describes the evolution of pesticide resistance in a population of insects?
a. Insects observe the behavior of other insects that survive pesticide application, and adjust their own behaviors to copy those of the survivors.
b. Individual members of the population slowly adapt to the presence of the chemical by striving to meet the new challenge.
c. Offspring of insects that are genetically resistant to the pesticide become more abundant as the susceptible insects die off.
d. All insects exposed to the insecticide begin to use a formerly silent gene to make a new enzyme that breaks down the insecticide molecules. |
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DDT was once considered a "silver bullet" that would permanently eradicate insect pests. Today, instead, DDT is largely useless against many insects. Which of these would have been required for this pest eradication effort to be successful in the long run?
a. None of the individual insects should have possessed genomes that made them resistant to DDT.
b. The frequency of DDT application should have been higher.
c. Larger doses of DDT should have been applied.
d. DDT application should have been continual.
e. All habitats should have received applications of DDT at about the same time. |
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Of the following anatomical structures, which is homologous to the wing of a bird?
a. Dorsal fin of a shark
b. Tail fin of a flying fish
c. Wing of a butterfly
d. Hindlimb of a kangaroo
e. Flipper of a cetacean |
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If two modern organisms are distantly related in an evolutionary sense, then one should expect that
a. they shared a common ancestor relatively recently.
b. they should share fewer homologous structures than two more closely related organisms.
c. they should be members of the same genus.
d. their chromosomes should be very similar.
e. they live in very different habitats. |
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Which of the following pieces of evidence most strongly supports the common origin of all life on Earth?
a. All organisms show heritable variation.
b. All organisms have undergone evolution.
c. All organisms require energy.
d. All organisms use essentially the same genetic code.
e. All organisms reproduce. |
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Members of two different species possess a similar-looking structure that they use in a similar fashion to perform the same function. Which information would best help distinguish between an explanation based on homology versus one based on convergent evolution?
a. Both species are well adapted to their particular environments.
b. Both species reproduce sexually.
c. The sizes of the structures in adult members of both species are similar in size.
d. The two species live at great distance from each other.
e. The two species share many proteins in common, and the nucleotide sequences that code for these proteins are almost identical. |
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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. homologous.
b. examples of convergent evolution.
c. adaptations to a common environment.
d. A and C only
e. B and C only |
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DNA sequences in many human genes are very similar to the sequences of corresponding genes in chimpanzees. The most likely explanation for this result is that
a. chimpanzees evolved from humans.
b. humans evolved from chimpanzees.
c. humans and chimpanzees are not closely related.
d. convergent evolution led to the DNA similarities.
e. humans and chimpanzees share a relatively recent common ancestor. |
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Which of the following pairs of structures is least likely to represent homology?
a. The brain of a cat and that of a dog
b. The hemoglobin of a baboon and that of a gorilla
c. The wings of a bat and the arms of a human
d. The mitochondria of a plant and those of an animal
e. The wings of a bird and those of an insect |
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Which of these is a statement that Darwin would have rejected?
a. The smallest entity that can evolve is an individual organism.
b. Environmental change plays a role in evolution.
c. Individuals can acquire new characteristics as they respond to new environments or situations.
d. Natural populations tend to produce more offspring than the environment can support.
e. Inherited variation in a population is a necessary precondition for natural selection to operate. |
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Which of these is the smallest unit that natural selection can change?
a. an individual's genotype
b. a species' gene frequency
c. an individual's genome
d. an individual's phenotype
e. a population's gene frequency |
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Which of these evolutionary agents is most consistent at causing populations to become better suited to their environments over the course of generations?
a. Gene flow
b. Mutation
c. Natural selection
d. Non-random mating
e. Genetic drift |
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Each of the following has a better chance of influencing gene frequencies in small populations than in large populations, but which one most consistently requires a small population as a precondition for its occurrence?
a. Genetic drift
b. Mutation
c. Natural selection
d. Non-random mating
e. Gene flow |
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The DNA polymerases of all cellular organisms have proofreading capability. This capability tends to reduce the introduction of
a. proofreading capability into prokaryotes.
b. extra genes by gene duplication events.
c. chromosomal translocation.
d. genetic variation by mutations. |
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If four of the original colonists died before they produced offspring, the ratios of genotypes could be quite different in the subsequent generations. This would be an example of
a. stabilizing selection.
b. diploidy.
c. disruptive selection.
d. genetic drift.
e. gene flow. |
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Over time, the movement of people on Earth has steadily increased. This has altered the course of human evolution by increasing
a. geographic isolation.
b. gene flow.
c. mutations.
d. genetic drift.
e. non-random mating. |
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Gene flow is a concept best used to describe an exchange between
a. individuals.
b. males and females.
c. species.
d. populations.
e. chromosomes. |
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The Darwinian fitness of an individual is measured most directly by
a. the number of "good genes" it possesses.
b. the number of mates it attracts.
c. the number of its offspring that survive to reproduce.
d. its physical strength.
e. how long it lives. |
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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. utilizes resources more efficiently than other species occupying similar niches.
c. leaves more viable offspring than others of its species.
d. competes for resources more successfully than others of its species.
e. mates more frequently than others of its species. |
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Which describes brightly colored peacocks mating more frequently than drab peacocks?
a. stabilizing selection
b. artificial selection
c. directional selection
d. sexual selection
e. disruptive selection |
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Most Swiss starlings produce four to five eggs in each clutch. Those producing fewer or more than this have reduced fitness. Which of the following terms best describes this?
a. artificial selection
b. disruptive selection
c. stabilizing selection
d. sexual selection
e. directional selection |
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Fossil evidence indicates that horses have gradually increased in size over geologic time. Which of the following terms best describes this?
a. artificial selection
b. stabilizing selection
c. sexual selection
d. disruptive selection
e. directional selection |
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The average birth weight for human babies is about 3 kg. Which of the following terms best describes this?
a. disruptive selection
b. artificial selection
c. directional selection
d. sexual selection
e. stabilizing selection |
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A certain species of land snail exists as either a cream color or a solid brown color. Intermediate individuals are relatively rare. Which of the following terms best describes this?
a. disruptive selection
b. directional selection
c. stabilizing selection
d. sexual selection
e. artificial selection |
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Cattle breeders have improved the quality of meat over the years by which process?
a. artificial selection
b. directional selection
c. stabilizing selection
d. A and B
e. A and C |
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Natural selection changes allele frequencies in populations because some ____ survive and reproduce more successfully than others.
a. gene pools
b. species
c. individuals
d. alleles
e. loci |
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Sparrows with average-sized wings survive severe storms better than those with longer or shorter wings, illustrating
a. stabilizing selection.
b. neutral variation.
c. frequency-dependent selection.
d. disruptive selection.
e. the bottleneck effect. |
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