In the mid-1900s, the Soviet geneticist Lysenko believed that his winter wheat plants, exposed
to ever-colder temperatures, would eventually give rise to ever more cold-tolerant winter wheat.
Lysenko's attempts in this regard were most in agreement with the ideas of
A) Cuvier.
B) Hutton.
C) Lamarck.
D) Darwin.
E) Lyell.

Lamarck.

Charles Darwin was the first person to propose
A) that evolution occurs.
B) a mechanism for how evolution occurs.
C) that Earth is older than a few thousand years.
D) a mechanism for evolution that was supported by evidence.
E) that population growth can outpace the growth of food resources.

a mechanism for evolution that was supported by evidence.

Which of these conditions should completely prevent the occurrence of natural selection in a
population over time?
A) All variation between individuals is due only to environmental factors.
B) The environment is changing at a relatively slow rate.
C) The population size is large.
D) The population lives in a habitat where there are no competing species present.

All variation between individuals is due only to environmental factors.

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) individuals who survive longer tend to leave more offspring than those who die young.
D) populations tend to produce more individuals than the environment can support.
E) individuals adapt to their environments, and thereby evolve.

individuals adapt to their environments, and thereby evolve.

Which of the following represents an idea that Darwin learned from the writings of Thomas
Malthus?
A) Technological innovation in agricultural practices will permit exponential growth of the
human population into the foreseeable future.
B) Populations tend to increase at a faster rate than their food supply normally allows.
C) Earth changed over the years through a series of catastrophic upheavals.
D) The environment is responsible for natural selection.
E) Earth is more than 10,000 years old.

Populations tend to increase at a faster rate than their food supply normally allows.

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) 2 → 4 → 1 → 3
B) 4 → 2 → 1 → 3
C) 4 → 1 → 2 → 3
D) 4 → 2 → 3 → 1
E) 2 → 4 → 3 → 1

2 → 4 → 1 → 3

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 both 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 parental generation of squirrels developed better eyesight due to improved diet; the
subsequent squirrel generation inherited better eyesight.
C) The number of predators that prey upon squirrels may have decreased.
D) A and C could be true.
E) A, B, and C could be true.

A and C could be true.

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) Three of the responses are correct.
E) Two of the responses are correct.

genetic variation among individuals

Which of Darwin's ideas had the strongest connection to Darwin having read Malthus's essay
on human population growth?
A) descent with modification
B) variation among individuals in a population
C) struggle for existence
D) the ability of related species to be conceptualized in "tree thinking"
E) that the ancestors of the Galápagos finches had come from the South American mainland

struggle for existence

If Darwin had been aware of genes, and of their typical mode of transmission to subsequent
generations, with which statement would he most likely have been in agreement?
A) If natural selection can change one gene's frequency in a population over the course of
generations, then, given enough time and enough genes, natural selection can cause sufficient
genetic change to produce new species from old ones.
B) If an individual's somatic cell genes change during its lifetime, making it more fit, then it will
be able to pass these genes on to its offspring.
C) If an individual acquires new genes by engulfing, or being infected by, another organism, then
a new genetic species will be the result.
D) A single mutation in a single gene in a single gamete will, if perpetuated, produce a new
species within just two generations.

If natural selection can change one gene's frequency in a population over the course of
generations, then, given enough time and enough genes, natural selection can cause sufficient genetic change to produce new species from old ones.

The role that humans play in artificial selection is to
A) determine who lives and who dies.
B) create the genetic variants, which nature then selects.
C) choose which organisms breed, and which do not.
D) train organisms to breed more successfully.
E) perform artificial insemination.

choose which organisms breed, and which do not.

In a hypothetical environment, fishes called pike-cichlids are visual predators of algae-eating
fish (in other words, they locate their prey by sight). If a population of algae-eaters experiences
predation pressure from pike-cichlids, which of the following is least likely to be observed in the
algae-eater population over the course of many generations?
A) selection for drab coloration of the algae-eaters
B) selection for nocturnal algae-eaters (active only at night)
C) selection for larger female algae-eaters, bearing broods composed of more, and larger, young
D) selection for algae-eaters that become sexually mature at smaller overall body sizes
E) selection for algae-eaters that are faster swimmers

selection for larger female algae-eaters, bearing broods composed of more, and larger, young

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) Larger doses of DDT should have been applied.
B) All habitats should have received applications of DDT at about the same time.
C) The frequency of DDT application should have been higher.
D) None of the individual insects should have possessed genomes that made them resistant to
DDT.
E) DDT application should have been continual.

None of the individual insects should have possessed genomes that made them resistant to
DDT.

Which of the following statements best describes theories?
A) They are nearly the same things as hypotheses.
B) They are supported by, and make sense of, many observations.
C) They cannot be tested because the described events occurred only once.
D) They are predictions of future events.

They are supported by, and make sense of, many observations.

Currently, two extant elephant species (X and Y) are placed in the genus Loxodonta, and a
third species (Z) is placed in the genus Elephas. Thus, which statement should be true?
A) Species X and Y are not related to species Z.
B) Species X and Y share a greater number of homologies with each other than either does with
species Z.
C) Species X and Y share a common ancestor that is still extant (in other words, not yet extinct).
D) Species X and Y are the result of artificial selection from an ancestral species Z.
E) Species X, Y, and Z share a common ancestor, but nothing more can be claimed than this.

Species X and Y share a greater number of homologies with each other than either does with
species Z.

The rise of methicillin-resistant Staphylococcus aureus (MRSA) can be considered to be an
example of artificial selection because
A) humans purposefully raise MRSA in large fermenters in an attempt to make the bacteria ever-
more resistant.
B) S. aureus is cultivated by humans to replenish the soil with nutrients.
C) humans synthesize methicillin and create environments in which bacteria frequently come
into contact with methicillin.
D) Humans are becoming resistant to bacteria by taking methicillin.

humans synthesize methicillin and create environments in which bacteria frequently come
into contact with methicillin.

Two plant species live in the same biome but on different continents. Although the two
species are not at all closely related, they may appear quite similar as a result of
A) parallel evolution.
B) convergent evolution.
C) allopatric speciation.
D) introgression.
E) gene flow.

convergent evolution.

If the bacterium Staphylococcus aureus experiences a cost for maintaining one or more
antibiotic-resistance genes, then what should happen in environments from which antibiotics are
missing?
A) These genes should continue to be maintained in case the antibiotics ever appear.
B) These bacteria should be outcompeted and replaced by bacteria that have lost these genes.
C) The bacteria should try to make the cost worthwhile by locating, and migrating to,
microenvironments where traces of antibiotics are present.
D) The bacteria should start making and secreting their own antibiotics.

These bacteria should be outcompeted and replaced by bacteria that have lost these genes.

Of the following anatomical structures, which is homologous to the bones in the wing of a
bird?
A) cartilage in the dorsal fin of a shark
B) bones in the hind limb of a kangaroo
C) chitinous struts in the wing of a butterfly
D) bony rays in the tail fin of a flying fish
E) bones in the flipper of a whale

bones in the flipper of a whale

If two modern organisms are distantly related in an evolutionary sense, then one should
expect that
A) they live in very different habitats.
B) they should share fewer homologous structures than two more closely related organisms.
C) their chromosomes should be very similar.
D) they shared a common ancestor relatively recently.
E) they should be members of the same genus.

they should share fewer homologous structures than two more closely related organisms.

Structures as different as human arms, bat wings, and dolphin flippers contain many of the
same bones, these bones having developed from very similar embryonic tissues. How do
biologists interpret these similarities?
A) by identifying the bones as being homologous structures
B) by the principle of convergent evolution
C) by proposing that humans, bats, and dolphins share a common ancestor
D) Three of the statements above are correct.
E) Two of the statements above are correct.

Two of the statements above are correct.

Over evolutionary time, many cave-dwelling organisms have lost their eyes. Tapeworms
have lost their digestive systems. Whales have lost their hind limbs. How can natural selection
account for these losses?
A) Natural selection cannot account for losses, only for innovations.
B) Natural selection accounts for these losses by the principle of use and disuse.
C) Under particular circumstances that persisted for long periods, each of these structures
presented greater costs than benefits.
D) The ancestors of these organisms experienced harmful mutations that forced them to find new
habitats that these species had not previously used.

Under particular circumstances that persisted for long periods, each of these structures
presented greater costs than benefits.

Which of the following pieces of evidence most strongly supports the common origin of all
life on Earth?
A) All organisms require energy.
B) All organisms use essentially the same genetic code.
C) All organisms reproduce.
D) All organisms show heritable variation.
E) All organisms have undergone evolution.

All organisms use essentially the same genetic code.

Logically, which of these should cast the most doubt on the relationships depicted by an
evolutionary tree?
A) None of the organisms depicted by the tree ate the same foods.
B) Some of the organisms depicted by the tree had lived in different habitats.
C) The skeletal remains of the organisms depicted by the tree were incomplete (in other words,
some bones were missing).
D) Transitional fossils had not been found.
E) Relationships between DNA sequences among the species did not match relationships
between skeletal patterns.

Relationships between DNA sequences among the species did not match relationships between skeletal patterns.

Which of the following statements most detracts from the claim that the human appendix is a
completely vestigial organ?
A) The appendix can be surgically removed with no immediate ill effects.
B) The appendix might have been larger in fossil hominids.
C) The appendix has a substantial amount of defensive lymphatic tissue.
D) Individuals with a larger-than-average appendix leave fewer offspring than those with a
below-average-sized appendix.
E) In a million years, the human species might completely lack an appendix.

The appendix has a substantial amount of defensive lymphatic tissue.