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Thursday, April 7, 2011

200+ question study guide for evolution concepts

( Answers on other post) as of April
AP Evolution Study List

Multiple Choice
Identify the choice that best completes the statement or answers the question.

____    1.   How might identical and obviously duplicated gene sequences have gotten from one chromosome to another?
a.
by normal meiotic recombination
b.
by normal mitotic recombination between sister chromatids
c.
by transcription followed by recombination
d.
by chromosomal translocation
e.
by deletion followed by insertion


____    2.   Several of the different globin genes are expressed in humans, but at different times in development. What mechanism could allow for this?
a.
exon shuffling
b.
intron activation
c.
pseudogene activation
d.
differential translation of mRNAs
e.
differential gene regulation over time


____    3.   What is it that can be duplicated in a genome?
a.
DNA sequences above a minimum size only
b.
DNA sequences below a minimal size only
c.
entire chromosomes only
d.
entire sets of chromosomes only
e.
sequences, chromosomes, or sets of chromosomes


____    4.   Unequal crossing over during Prophase I can result in one sister chromosome with a deletion and another with a duplication. A mutated form of hemoglobin, known as hemoglobin Lepore, is known in the human population. Hemoglobin Lepore has a deleted set of amino acids. If it was caused by unequal crossing over, what would be an expected consequence?
a.
If it is still maintained in the human population, hemoglobin Lepore must be selected for in evolution.
b.
There should also be persons born with, if not living long lives with, an anti-Lepore mutation or duplication.
c.
Each of the genes in the hemoglobin gene family must show the same deletion.
d.
The deleted gene must have undergone exon shuffling
e.
The deleted region must be located in a different area of the individual's genome.


____    5.   When does exon shuffling occur?
a.
during splicing of DNA
b.
during mitotic recombination
c.
as an alternative splicing pattern in post-transcriptional processing
d.
as an alternative cleavage or modification post-translationally
e.
as the result of faulty DNA repair


____    6.   In order to determine the probable function of a particular sequence of DNA in humans, what might be the most reasonable approach?
a.
Prepare a knockout mouse without a copy of this sequence and examine the mouse phenotype.
b.
Genetically engineer a mouse with a copy of this sequence and examine its phenotype.
c.
Look for a reasonably identical sequence in another species, prepare a knockout of this sequence in that species and look for the consequences.
d.
Prepare a genetically engineered bacterial culture with the sequence inserted and assess which new protein is synthesized.
e.
Mate two individuals heterozygous for the normal and mutated sequences.


____    7.   What does the field often called "evo-devo" study?
a.
whether or not development is an evolutionary process
b.
how developmental processes have evolved
c.
whether or not all animals have developmental regulation
d.
whether the pattern of human development evolved early or late
e.
whether or not there are specific genes controlling development


____    8.   Homeotic genes contain a homeobox sequence that is highly conserved among very diverse species. The homeobox is the code for that domain of a protein that binds to DNA in a regulatory developmental process. Which of the following would you then expect?
a.
That homeotic genes are selectively expressed over developmental time.
b.
That a homeobox containing gene has to be a developmental regulator.
c.
That homeoboxes cannot be expressed in non-homeotic genes.
d.
That all organisms must have homeotic genes.
e.
That all organisms must have homeobox containing genes.


____    9.   Homeotic genes
a.
encode transcription factors that control the expression of genes responsible for specific anatomical structures.
b.
are found only in Drosophila and other arthropods.
c.
are the only genes that contain the homeobox domain.
d.
encode proteins that form anatomical structures in the fly.
e.
are responsible for patterning during plant development.


____   10.   Although quite different in structure, plants and animals share some basic similarities in their development, such as
a.
the importance of cell and tissue movements.
b.
the importance of selective cell enlargement.
c.
the importance of homeobox-containing homeotic genes.
d.
a common evolutionary origin of the complete developmental program.
e.
a cascade of transcription factors that regulate gene expression on a finer and finer scale.


____   11.   Catastrophism, meaning the regular occurrence of geological or meteorological disturbances (catastrophes), was Cuvier's attempt to explain the existence of
a.
evolution.
b.
the fossil record.
c.
uniformitarianism.
d.
the origin of new species.
e.
natural selection.


____   12.   Which of the events described below agrees with the idea of catastrophism?
a.
The gradual uplift of the Himalayas by the collision of the Australian crustal plate with the Eurasian crustal plate
b.
The formation of the Grand Canyon by the Colorado River over millions of years
c.
The gradual deposition of sediments many kilometers thick on the floors of seas and oceans
d.
The sudden demise of the dinosaurs, and various other groups, by the impact of a large extraterrestrial body with Earth
e.
The development of the Galapagos Islands from underwater seamounts over millions of years


____   13.   What was the prevailing notion prior to the time of Lyell and Darwin?
a.
Earth is a few thousand years old, and populations are unchanging.
b.
Earth is a few thousand years old, and populations gradually change.
c.
Earth is millions of years old, and populations rapidly change.
d.
Earth is millions of years old, and populations are unchanging.
e.
Earth is millions of years old, and populations gradually change.


____   14.   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.
Characteristics acquired during an organism's life are generally not passed on through genes.
b.
Spontaneous mutations can result in the appearance of new traits.
c.
Only favorable adaptations have survival value.
d.
Disuse of an organ may lead to its eventual disappearance.
e.
Overproduction of offspring leads to a struggle for survival.


____   15.   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.
Plato.


____   16.   Darwin's mechanism of natural selection required long time spans in order to modify species. From whom did Darwin get the concept of Earth's ancient age?
a.
Georges Cuvier
b.
Charles Lyell
c.
Alfred Wallace
d.
Thomas Malthus
e.
John Henslow


____   17.   As a young biologist, Charles Darwin had expected the living plants of temperate South America would resemble those of temperate Europe, but he was surprised to find that they more closely resembled the plants of tropical South America. The biological explanation for this observation is most properly associated with the field of
a.
meteorology.
b.
embryology.
c.
vertebrate anatomy.
d.
bioengineering.
e.
biogeography.


____   18.   Which of these naturalists synthesized a concept of natural selection independently of Darwin?
a.
Charles Lyell
b.
Gregor Mendel
c.
Alfred Wallace
d.
John Henslow
e.
Thomas Malthus


____   19.   Charles Darwin was the first person to propose
a.
that evolution occurs.
b.
a mechanism for how evolution occurs.
c.
that the Earth is older than a few thousand years.
d.
a mechanism for evolution that was supported by evidence.
e.
a way to use artificial selection as a means of domesticating plants and animals.


____   20.   In Darwin's thinking, the more closely related two different organisms are, the
a.
more similar their habitats are.
b.
less similar their DNA sequences are.
c.
more recently they shared a common ancestor.
d.
less likely they are to have the same genes in common.
e.
more similar they are in size.


____   21.   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.


____   22.   Which of the following represents an idea that Darwin learned from the writings of Thomas Malthus?
a.
All species are fixed in the form in which they are created.
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.


____   23.   Which statement about natural selection is most correct?
a.
Adaptations beneficial in one habitat should generally be beneficial in all other habitats as well.
b.
Different species that occupy the same habitat will adapt to that habitat by undergoing the same genetic changes.
c.
Adaptations beneficial at one time should generally be beneficial during all other times as well.
d.
Well-adapted individuals leave more offspring, and thus contribute more to the next generation's gene pool, than do poorly adapted individuals.
e.
Natural selection is the sole means by which populations can evolve.


____   24.   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


____   25.   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


____   26.   To observe natural selection's effects on a population, which of these must be true?
a.
One must observe more than one generation of the population.
b.
The population must contain genetic variation.
c.
Members of the population must increase or decrease the use of some portion of their anatomy.
d.
A and C only
e.
A and B only


____   27.   During drought years on the Galapagos, small, easily eaten seeds become rare, leaving mostly large, hard-cased seeds that only birds with large beaks can eat. If a drought persists for several years, what should one expect to result from natural selection?
a.
Small birds gaining larger beaks by exercising their mouth parts.
b.
Small birds mutating their beak genes with the result that later-generation offspring have larger beaks.
c.
Small birds anticipating the long drought and eating more to gain weight and, consequently, growing larger beaks.
d.
More small-beaked birds dying than larger-beaked birds. The offspring produced in subsequent generations have a higher percentage of birds with large beaks.
e.
Larger birds eating less so smaller birds can survive.


____   28.   Which of the following statements is an inference of natural selection?
a.
Subsequent generations of a population should have greater proportions of individuals that possess traits better suited for success in unchanging environments.
b.
An individual organism undergoes evolution over the course of its lifetime.
c.
Habitats do not generally have unlimited resources.
d.
Natural populations tend to reproduce to their full biological potential.
e.
Some of the variation that exists among individuals in a population is genetic.


____   29.   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


____   30.   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 Galapagos finches had come from the South American mainland


The following questions refer to the evolutionary tree in Figure 22.2.

The tree's horizontal axis is a timeline that extends from 100,000 years ago to the present; the vertical axis represents nothing in particular. The labeled branch points on the tree (V—Z) represent various common ancestors. Let's say that only since 50,000 years ago has there been enough variation between the lineages depicted here to separate them into distinct species, and only the tips of the lineages on this tree represent distinct species.


Figure 22.2

____   31.   How many separate species, both extant and extinct, are depicted in this tree?
a.
2
b.
3
c.
4
d.
5
e.
6


____   32.   According to this tree, what percent of the species seem to be extant (i.e., not extinct)?
a.
25%
b.
33%
c.
50%
d.
66%
e.
75%


____   33.   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.
W
c.
X
d.
Y
e.
Z


____   34.   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.
Y
e.
Z


____   35.   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.
V
b.
W
c.
X
d.
Y
e.
Z


____   36.   Evolutionary trees such as this are properly understood by scientists to be
a.
theories.
b.
hypotheses.
c.
laws.
d.
dogmas.
e.
facts.


____   37.   In a hypothetical environment, fishes called pike-cichlids are visual predators of algae-eating fish (i.e., they locate their prey by sight). If a population of algae-eaters experiences predation pressure from pike-cichlids, which of the following should least likely 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


____   38.   Which statement best describes the evolution of pesticide resistance in a population of insects?
a.
Individual members of the population slowly adapt to the presence of the chemical by striving to meet the new challenge.
b.
All insects exposed to the insecticide begin to use a formerly silent gene to make a new enzyme that breaks down the insecticide molecules.
c.
Insects observe the behavior of other insects that survive pesticide application, and adjust their own behaviors to copy those of the survivors.
d.
Offspring of insects that are genetically resistant to the pesticide become more abundant as the susceptible insects die off.


____   39.   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.


____   40.   Some members of a photosynthetic plant species are genetically resistant to an herbicide, while other members of the same species are not resistant to the herbicide. Which combination of events should cause the most effective replacement of the non-herbicide-resistant strain of plants by the resistant strain?
1.
The presence of the herbicide in the environment
2.
The absence of the herbicide from the environment
3.
The maintenance of the proper conditions for one generation
4.
The maintenance of the proper conditions for many generations

a.
1 and 3
b.
1 and 4
c.
2 and 3
d.
2 and 4


____   41.   Of the following anatomical structures, which is homologous to the wing of a bird?
a.
Dorsal fin of a shark
b.
Hindlimb of a kangaroo
c.
Wing of a butterfly
d.
Tail fin of a flying fish
e.
Flipper of a cetacean


____   42.   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.


____   43.   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
b.
By the principle of convergent evolution
c.
By proposing that humans, bats, and dolphins share a common ancestor
d.
A and C only
e.
A, B, and C


____   44.   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.


____   45.   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.


____   46.   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 (i.e., 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.


____   47.   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.


____   48.   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


____   49.   It has been observed that organisms on islands are different from, but closely related to, similar forms found on the nearest continent. This is taken as evidence that
a.
island forms and mainland forms descended from common ancestors.
b.
common environments are inhabited by the same organisms.
c.
the islands were originally part of the continent.
d.
the island forms and mainland forms are converging.
e.
island forms and mainland forms have identical gene pools.


____   50.   The theory of evolution is most accurately described as
a.
an educated guess about how species originate.
b.
one possible explanation, among several scientific alternatives, about how species have come into existence.
c.
an opinion that some scientists hold about how living things change over time.
d.
an overarching explanation, supported by much evidence, for how populations change over time.
e.
an idea about how acquired characteristics are passed on to subsequent generations.


____   51.   Which of the following is not an observation or inference on which natural selection is based?
a.
There is heritable variation among individuals.
b.
Poorly adapted individuals never produce offspring.
c.
Species produce more offspring than the environment can support.
d.
Individuals whose characteristics are best suited to the environment generally leave more offspring than those whose characteristics are less suited.
e.
Only a fraction of the offspring produced by an individual may survive.


____   52.   The upper forelimbs of humans and bats have fairly similar skeletal structures, whereas the corresponding bones in whales have very different shapes and proportions. However, genetic data suggest that all three kinds of organisms diverged from a common ancestor at about the same time. Which of the following is the most likely explanation for these data?
a.
Humans and bats evolved by natural selection, and whales evolved by Lamarckian mechanisms.
b.
Forelimb evolution was adaptive in people and bats, but not in whales.
c.
Natural selection in an aquatic environment resulted in significant changes to whale forelimb anatomy.
d.
Genes mutate faster in whales than in humans or bats.
e.
Whales are not properly classified as mammals.


____   53.   Which of the following observations helped Darwin shape his concept of descent with modification?
a.
Species diversity declines farther from the equator.
b.
Fewer species live on islands than on the nearest continents.
c.
Birds can be found on islands located farther from the mainland than the birds' maximum nonstop flight distance.
d.
South American temperate plants are more similar to the tropical plants of South America than to the temperate plants of Europe.
e.
Earthquakes reshape life by causing mass extinctions.


____   54.   Within a few weeks of treatment with the drug 3TC, a patient's HIV population consists entirely of 3TC-resistant viruses. How can this result best be explained?
a.
HIV can change its surface proteins and resist vaccines.
b.
The patient must have become reinfected with 3TC-resistant viruses.
c.
HIV began making drug-resistant versions of reverse transcriptase in response to the drug.
d.
A few drug-resistant viruses were present at the start of treatment, and natural selection increased their frequency.
e.
The drug caused the HIV RNA to change.


____   55.   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.
humans and chimpanzees share a relatively recent common ancestor.
b.
humans evolved from chimpanzees.
c.
chimpanzees evolved from humans.
d.
convergent evolution led to the DNA similarities.
e.
humans and chimpanzees are not closely related.


____   56.   Which of the following pairs of structures is least likely to represent homology?
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


____   57.   Which of these is a statement that Darwin would have rejected?
a.
Environmental change plays a role in evolution.
b.
The smallest entity that can evolve is an individual organism.
c.
Individuals can acquire new characteristics as they respond to new environments or situations.
d.
Inherited variation in a population is a necessary precondition for natural selection to operate.
e.
Natural populations tend to produce more offspring than the environment can support.


____   58.   About which of these did Darwin have a poor understanding?
a.
that individuals in a population exhibit a good deal of variation
b.
that much of the variation between individuals in a population is inherited
c.
the factors that cause individuals in populations to struggle for survival
d.
the sources of genetic variations among individuals
e.
how a beneficial trait becomes more common in a population over the course of generations


____   59.   If, on average, 46% of the loci in a species' gene pool are heterozygous, then the average homozygosity of the species should be
a.
23%
b.
46%
c.
54%
d.
92%
e.
There is not enough information to say.


____   60.   Which of these is the smallest unit upon which natural selection directly acts?
a.
a species' gene frequency
b.
a population's gene frequency
c.
an individual's genome
d.
an individual's genotype
e.
an individual's phenotype


____   61.   Which of these evolutionary agents is most consistent at causing populations to become better suited to their environments over the course of generations?
a.
Mutation
b.
Non-random mating
c.
Gene flow
d.
Natural selection
e.
Genetic drift


____   62.   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.
Mutation
b.
Non-random mating
c.
Genetic drift
d.
Natural selection
e.
Gene flow


____   63.   In modern terminology, diversity is understood to be a result of genetic variation. Sources of variation for evolution include all of the following except
a.
mistakes in translation of structural genes.
b.
mistakes in DNA replication.
c.
translocations and mistakes in meiosis.
d.
recombination at fertilization.
e.
recombination by crossing over in meiosis.


____   64.   A trend toward the decrease in the size of plants on the slopes of mountains as altitudes increase is an example of
a.
a cline.
b.
a bottleneck.
c.
relative fitness.
d.
genetic drift.
e.
geographic variation.


____   65.   If two genes from one RNA molecule become detached and then, as a unit, get attached to one end of the other RNA molecule within a single HIV particle, which of these is true?
a.
There are now fewer genes within the viral particle.
b.
There are now more genes within the viral particle.
c.
A point substitution mutation has occurred in the retroviral genome.
d.
The retroviral equivalent of crossing-over has occurred, no doubt resulting in a heightened positive effect.
e.
One of the RNA molecules has experienced gene duplication as the result of translocation.


____   66.   The DNA polymerases of all cellular organisms have proofreading capability. This capability tends to reduce the introduction of
a.
extra genes by gene duplication events.
b.
chromosomal translocation.
c.
genetic variation by mutations.
d.
proofreading capability into prokaryotes.


____   67.   Which of these makes determining the evolutionary relatedness of different species based on the amino acid sequence of homologous proteins generally less accurate than determinations of relatedness based on the nucleotide sequences of homologous genes?
a.
Silent mutations
b.
Gene duplications
c.
Translocation events that change gene sequences
d.
Crossing-over
e.
Independent assortment


____   68.   Which is a true statement concerning genetic variation?
a.
It is created by the direct action of natural selection.
b.
It arises in response to changes in the environment.
c.
It must be present in a population before natural selection can act upon the population.
d.
It tends to be reduced by the processes involved when diploid organisms produce gametes.
e.
A population that has a higher average heterozygosity has less genetic variation than one with a larger average heterozygosity.


Use the following information to answer the questions below.

A large population of laboratory animals has been allowed to breed randomly for a number of generations. After several generations, 25% of the animals display a recessive trait (aa), the same percentage as at the beginning of the breeding program. The rest of the animals show the dominant phenotype, with heterozygotes indistinguishable from the homozygous dominants.

____   69.   What is the most reasonable conclusion that can be drawn from the fact that the frequency of the recessive trait (aa) has not changed over time?
a.
The population is undergoing genetic drift.
b.
The two phenotypes are about equally adaptive under laboratory conditions.
c.
The genotype AA is lethal.
d.
There has been a high rate of mutation of allele A to allele a.
e.
There has been sexual selection favoring allele a.


____   70.   What is the estimated frequency of allele A in the gene pool?
a.
0.05
b.
0.25
c.
0.50
d.
0.75
e.
1.00


____   71.   What proportion of the population is probably heterozygous (Aa) for this trait?
a.
0.05
b.
0.25
c.
0.50
d.
0.75
e.
1.00


____   72.   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.
4
b.
16
c.
32
d.
36
e.
40


____   73.   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.
90
b.
81
c.
49
d.
18
e.
10


____   74.   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.
0.20
b.
0.32
c.
0.42
d.
0.80
e.
Genotype frequency cannot be determined from the information provided.


____   75.   You sample a population of butterflies and find that 42% are heterozygous at a particular locus. What should be the frequency of the recessive allele in this population?
a.
0.09
b.
0.30
c.
0.49
d.
0.70
e.
Allele frequency cannot be determined from this information.


Use the following information to answer the questions below.

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.

____   76.   What is the frequency of the B allele?
a.
0.001
b.
0.002
c.
0.100
d.
0.400
e.
0.600


____   77.   If there are 4,000 children born to this generation, how many would be expected to have AB blood under the conditions of Hardy-Weinberg equilibrium?
a.
100
b.
960
c.
1,920
d.
2,000
e.
2,400


____   78.   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.
0.36
b.
0.60
c.
0.64
d.
0.75
e.
0.80


The following questions refer to this information:

In the year 2500, five male space colonists and five female space colonists (all unrelated to each other) settle on an uninhabited Earthlike planet in the Andromeda galaxy. The colonists and their offspring randomly mate for generations. All ten of the original colonists had free earlobes, and two were heterozygous for that trait. The allele for free earlobes is dominant to the allele for attached earlobes.

____   79.   Which of these is closest to the allele frequency in the founding population?
a.
0.1 a, 0.9 A
b.
0.2 a, 0.8 A
c.
0.5 a, 0.5 A
d.
0.8 a, 0.2 A
e.
0.4 a, 0.6 A


____   80.   If one assumes that Hardy-Weinberg equilibrium applies to the population of colonists on this planet, about how many people will have attached earlobes when the planet's population reaches 10,000?
a.
100
b.
400
c.
800
d.
1,000
e.
10,000


____   81.   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.
diploidy.
b.
gene flow.
c.
genetic drift.
d.
disruptive selection.
e.
stabilizing selection.


The following questions refer to this information:

You are studying three populations of birds. Population A has ten birds, of which one is brown (a recessive trait) and nine are red. Population B has 100 birds, of which ten are brown. Population C has 30 birds, and three of them are brown.

____   82.   In which population is the frequency of the allele for brown feathers highest?
a.
Population A.
b.
Population B.
c.
Population C.
d.
They are all the same.
e.
It is impossible to tell from the information given.


____   83.   In which population would it be least likely that an accident would significantly alter the frequency of the brown allele?
a.
Population A.
b.
Population B.
c.
Population C.
d.
They are all the same.
e.
It is impossible to tell from the information given.


____   84.   Which population is most likely to be subject to the bottleneck effect?
a.
Population A.
b.
Population B.
c.
Population C.
d.
They are all the same.
e.
It is impossible to tell from the information given.


____   85.   You are maintaining a small population of fruit flies in the laboratory by transferring the flies to a new culture bottle after each generation. After several generations, you notice that the viability of the flies has decreased greatly. Recognizing that small population size is likely to be linked to decreased viability, the best way to reverse this trend is to
a.
cross your flies with flies from another lab.
b.
reduce the number of flies that you transfer at each generation.
c.
transfer only the largest flies.
d.
change the temperature at which you rear the flies.
e.
shock the flies with a brief treatment of heat or cold to make them more hardy.


____   86.   If the frequency of a particular allele that is present in a small, isolated population of alpine plants decreases due to a landslide that leaves an even smaller remnant of surviving plants bearing this allele, then what has occurred?
a.
a bottleneck
b.
genetic drift
c.
microevolution
d.
A and B only
e.
A, B, and C


____   87.   If the original finches that had been blown over to the Galapagos from South America had already been genetically different from the parental population of South American finches, even before adapting to the Galapagos, this would have been an example of
a.
genetic drift.
b.
bottleneck effect.
c.
founder's effect.
d.
all three of these
e.
both A and C


____   88.   Over time, the movement of people on Earth has steadily increased. This has altered the course of human evolution by increasing
a.
non-random mating.
b.
geographic isolation.
c.
genetic drift.
d.
mutations.
e.
gene flow.


____   89.   Gene flow is a concept best used to describe an exchange between
a.
species.
b.
males and females.
c.
populations.
d.
individuals.
e.
chromosomes.


____   90.   Natural selection is most nearly the same as
a.
diploidy.
b.
gene flow.
c.
genetic drift.
d.
non-random mating.
e.
differential reproductive success.


The following questions refer to this information:

The restriction enzymes of bacteria protect the bacteria from successful attack by bacteriophages, whose genomes can be degraded by the restriction enzymes. The bacterial genomes are not vulnerable to these restriction enzymes because bacterial DNA is methylated. This situation selects for bacteriophages whose genomes are also methylated. As new strains of resistant bacteriophages become more prevalent, this in turn selects for bacteria whose genomes are not methylated and whose restriction enzymes instead degrade methylated DNA.

____   91.   The outcome of the conflict between bacteria and bacteriophage at any point in time results from
a.
frequency-dependent selection.
b.
evolutionary imbalance.
c.
heterozygote advantage.
d.
neutral variation.
e.
genetic variation being preserved by diploidy.


____   92.   Over the course of evolutionary time, what should occur?
a.
Methylated DNA should become fixed in the gene pools of bacterial species.
b.
Nonmethylated DNA should become fixed in the gene pools of bacteriophages.
c.
Methylated DNA should become fixed in the gene pools of bacteriophages.
d.
Methylated and nonmethylated strains should be maintained among both bacteria and bacteriophages, with ratios that vary over time.
e.
Both A and B are correct.


____   93.   Arrange the following from most general (i.e., most inclusive) to most specific (i.e., least inclusive):
1. Natural selection
2. Microevolution
3. Intrasexual selection
4. Evolution
5. Sexual selection
a.
4, 1, 2, 3, 5
b.
4, 2, 1, 3, 5
c.
4, 2, 1, 5, 3
d.
1, 4, 2, 5, 3
e.
1, 2, 4, 5, 3


____   94.   Sexual dimorphism is most often a result of
a.
pansexual selection.
b.
stabilizing selection.
c.
intrasexual selection.
d.
intersexual selection.
e.
artificial selection.


The following questions refer to this information:

In the wild, male house finches (Carpodus mexicanus) vary considerably in the amount of red pigmentation in their head and throat feathers, with colors ranging from pale yellow to bright red. These colors come from carotenoid pigments that are found in the birds' diets; no vertebrates are known to synthesize carotenoid pigments. Thus, the brighter red the male's feathers are, the more successful he has been at acquiring the red carotenoid pigment by his food-gathering efforts (all other factors being equal).

____   95.   During breeding season, one should expect female house finches to prefer to mate with males with the brightest red feathers. Which of the following is true of this situation?
a.
Alleles that promote more efficient acquisition of carotenoid-containing foods by males should increase over the course of generations.
b.
Alleles that promote more effective deposition of carotenoid pigments in the feathers of males should increase over the course of generations.
c.
There should be directional selection for bright red feathers in males.
d.
All three of these.
e.
Only B and C.


____   96.   Which of the following terms are appropriately applied to the situation described in the previous question?
a.
Sexual selection
b.
Mate choice
c.
Intersexual selection
d.
All three of these
e.
Only B and C


____   97.   The situation as described in the paragraph above should select most directly against males that
a.
are unable to distinguish food items that are red from those of other colors.
b.
are older, but still healthy.
c.
are capable of defending only moderately sized territories.
d.
have slightly lower levels of testosterone during breeding season than have other males.
e.
have no prior experience courting female house finches.


The following questions refer to this information:

Adult male humans generally have deeper voices than do adult female humans, as the direct result of higher levels of testosterone causing growth of the larynx.

____   98.   If the fossil records of apes and humans alike show a trend toward decreasing larynx size in adult females, and increasing larynx size in adult males, then
a.
sexual dimorphism was developing over time in these species.
b.
intrasexual selection seems to have occurred.
c.
the "good genes" hypothesis was refuted by these data.
d.
stabilizing selection was occurring in these species concerning larynx size.
e.
selection was acting more directly upon genotype than upon phenotype.


____   99.   Which addition to the information in the paragraph above would make more than one of the answers listed in the previous question correct?
a.
If larynx size was also affected by the amount the larynx was used (i.e., the amount of vocalization).
b.
If males prefer to mate with females possessing higher voices.
c.
If females killed female offspring whose voices were too deep.
d.
If the trend described above was seen in the fossil record of only one species of ape.


____ 100.   If one excludes the involvement of gender in the situation described in the paragraph above, then the pattern that is apparent in the fossil record is most similar to one that should be expected from
a.
pansexual selection.
b.
directional selection.
c.
disruptive selection.
d.
stabilizing selection.
e.
asexual selection.


____ 101.   The Darwinian fitness of an individual is measured most directly by
a.
the number of its offspring that survive to reproduce.
b.
the number of "good genes" it possesses.
c.
the number of mates it attracts.
d.
its physical strength.
e.
how long it lives.


____ 102.   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.


____ 103.   Which of the following statements best summarizes evolution as it is viewed today?
a.
It is goal-directed.
b.
It represents the result 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.


____ 104.   If neutral variation is truly "neutral," then it should have no effect on
a.
nucleotide diversity.
b.
average heterozygosity.
c.
our ability to measure the rate of evolution.
d.
relative fitness.
e.
gene diversity.


____ 105.   Which describes an African butterfly species that exists in two strikingly different color patterns?
a.
artificial selection
b.
directional selection
c.
stabilizing selection
d.
disruptive selection
e.
sexual selection


____ 106.   Which describes brightly colored peacocks mating more frequently than drab peacocks?
a.
artificial selection
b.
directional selection
c.
stabilizing selection
d.
disruptive selection
e.
sexual selection


____ 107.   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.
directional selection
c.
stabilizing selection
d.
disruptive selection
e.
sexual selection


____ 108.   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.
directional selection
c.
stabilizing selection
d.
disruptive selection
e.
sexual selection


____ 109.   The average birth weight for human babies is about 3 kg. Which of the following terms best describes this?
a.
artificial selection
b.
directional selection
c.
stabilizing selection
d.
disruptive selection
e.
sexual selection


____ 110.   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.
artificial selection
b.
directional selection
c.
stabilizing selection
d.
disruptive selection
e.
sexual selection


____ 111.   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


____ 112.   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.
heterozygote advantage
b.
stabilizing selection
c.
diploidy
d.
balancing selection


____ 113.   Mules are relatively long-lived and hardy organisms that cannot, generally speaking, perform successful meiosis. Consequently, which statement about mules is true?
a.
They have a relative evolutionary fitness of zero.
b.
Their offspring have less genetic variation than the parents.
c.
Mutations cannot occur in their genomes.
d.
If crossing-over happens in mules, then it must be limited to prophase of mitosis.
e.
When two mules interbreed, genetic recombination cannot occur by meiotic crossing over, but only by the act of fertilization.


____ 114.   Heterozygote advantage should be most closely linked to which of the following?
a.
sexual selection
b.
stabilizing selection
c.
random selection
d.
directional selection
e.
disruptive selection


____ 115.   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.
disruptive selection
b.
directional selection
c.
stabilizing selection
d.
sexual selection
e.
No selection would operate because the population is in Hardy-Weinberg equilibrium.


In a very large population, a quantitative trait has the following distribution pattern:


Figure 23.1

____ 116.   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.


____ 117.   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.
1 only
b.
4 only
c.
2 and 3
d.
4 and 5
e.
1, 2, and 3


____ 118.   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.
artificial selection.
c.
sexual selection.
d.
natural selection.
e.
disruptive selection.


____ 119.   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.
sexual selection.
b.
disruptive selection.
c.
balancing selection.
d.
stabilizing selection.
e.
frequency-dependent selection.


____ 120.   The same gene that causes various coat patterns in wild and domesticated cats also causes the cross-eyed condition in these cats, the cross-eyed condition being slightly maladaptive. In a hypothetical environment, the coat pattern that is associated with crossed eyes is highly adaptive, with the result that both the coat pattern and the cross-eyed condition increase in a feline population over time. Which statement is supported by these observations?
a.
Evolution is progressive and tends toward a more perfect population.
b.
Phenotype is often the result of compromise.
c.
Natural selection reduces the frequency of maladaptive genes in populations over the course of time.
d.
Polygenic inheritance is generally maladaptive, and should become less common in future generations.
e.
In all environments, coat pattern is a more important survival factor than is eye-muscle tone.


____ 121.   A proficient engineer can easily design skeletal structures that are more functional than those currently found in the forelimbs of such diverse mammals as horses, whales, and bats. That the actual forelimbs of these mammals do not seem to be optimally arranged is because
a.
natural selection has not had sufficient time to create the optimal design in each case, but will do so given enough time.
b.
natural selection operates in ways that are beyond the capability of the human mind to comprehend.
c.
in many cases, phenotype is not merely determined by genotype, but by the environment as well.
d.
though we may not consider the fit between the current skeletal arrangements and their functions excellent, we should not doubt that natural selection ultimately produces the best design.
e.
natural selection is generally limited to modifying structures that were present in previous generations and in previous species.


____ 122.   There are those who claim that the theory of evolution cannot be true because the apes, which are supposed to be closely related to humans, do not likewise share the same large brains, capacity for complicated speech, and tool-making capability. They reason that if these features are generally beneficial, then the apes should have evolved them as well. Which of these provides the best argument against this misconception?
a.
Advantageous alleles do not arise on demand.
b.
A population's evolution is limited by historical constraints.
c.
Adaptations are often compromises.
d.
Evolution can be influenced by environmental change.


____ 123.   A fruit fly population has a gene with two alleles, A1 and A2. Tests show that 70% of the gametes produced in the population contain the A1 allele. If the population is in Hardy-Weinberg equilibrium, what proportion of the flies carry both A1 and A2?
a.
0.7
b.
0.49
c.
0.21
d.
0.42
e.
0.09


____ 124.   There are 40 individuals in population 1, all of which have genotype A1A1, and there are 25 individuals in population 2, all of genotype A2A2. Assume that these populations are located far from one another and that their environmental conditions are very similar. Based on the information given here, the observed genetic variation is mostly likely an example of
a.
genetic drift.
b.
gene flow.
c.
disruptive selection.
d.
discrete variation.
e.
directional selection.


____ 125.   Natural selection changes allele frequencies in populations because some ____ survive and reproduce more successfully than others.
a.
alleles
b.
loci
c.
gene pools
d.
species
e.
individuals


____ 126.   No two people are genetically identical, except for identical twins. The chief cause of genetic variation among human individuals is
a.
new mutations that occurred in the preceding generation.
b.
the reshuffling of alleles in sexual reproduction.
c.
genetic drift due to the small size of the population.
d.
geographic variation within the population.
e.
environmental effects.


____ 127.   Sparrows with average-sized wings survive severe storms better than those with longer or shorter wings, illustrating
a.
the bottleneck effect.
b.
stabilizing selection.
c.
frequency-dependent selection.
d.
neutral variation.
e.
disruptive selection.


____ 128.   Which of the following statements about species, as defined by the biological species concept, is (are) correct?
I.
Biological species are defined by reproductive isolation.
II.
Biological species are the model used for grouping extinct forms of life.
III.
The biological species is the largest unit of population in which successful reproduction is possible.

a.
I only
b.
II only
c.
I and III
d.
II and III
e.
I, II, and III


____ 129.   What is generally true of two very closely related species that have diverged from each other quite recently?
a.
They shared a common ancestor recently in evolutionary time.
b.
Genes are unable to pass from one species' gene pool to the other's gene pool.
c.
They are unable to produce hybrid offspring upon interbreeding.
d.
Their reproductive isolation from each other is complete.


____ 130.   Which of the various species concepts distinguishes two species based on the degree of genetic exchange between their gene pools?
a.
phylogenetic
b.
ecological
c.
biological
d.
morphological


____ 131.   Which species concept is currently most popular among most biologists?
a.
phylogenetic
b.
ecological
c.
biological
d.
morphological


____ 132.   There is still some controversy among biologists about whether Neanderthals should be placed within the same species as modern humans, or into a separate species of their own. Most DNA sequence data analyzed so far indicate that there was probably little or no gene flow between Neanderthals and Homo sapiens. Which species concept is most applicable in this example?
a.
phylogenetic
b.
ecological
c.
morphological
d.
biological


____ 133.   A biologist discovers two populations of wolf spiders whose members appear identical. Members of one population are found in the leaf litter deep within the woods. Members of the other population are found in the grass at the edge of the woods. The biologist decides to designate the members of the two populations as two separate species. Which species concept is this biologist most closely utilizing?
a.
ecological
b.
biological
c.
morphological
d.
phylogenetic


____ 134.   What was the species concept most used by Linnaeus?
a.
biological
b.
morphological
c.
ecological
d.
phylogenetic


____ 135.   You are confronted with a box of preserved grasshoppers of various species that are new to science and have not been described. Your assignment is to separate them into species. There is no accompanying information as to where or when they were collected. Which species concept will you have to use?
a.
biological
b.
phylogenetic
c.
ecological
d.
morphological


The questions below are based on the following description.

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. In each case, match the various descriptions of frogs below with the appropriate reproductive barrier listed.

____ 136.   Males of one species sing only when its predators are absent; males of another species sing only when its predators are present.
a.
behavioral
b.
gametic
c.
habitat
d.
temporal
e.
mechanical


____ 137.   One species lives only in tree holes; another species lives only in streams.
a.
behavioral
b.
gametic
c.
habitat
d.
temporal
e.
mechanical


____ 138.   Females of one species choose mates based on song quality; females of another species choose mates on the basis of size.
a.
behavioral
b.
gametic
c.
habitat
d.
temporal
e.
mechanical


____ 139.   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.
a.
behavioral
b.
gametic
c.
habitat
d.
temporal
e.
mechanical


____ 140.   Males of one species are too small to perform amplexus (an action that stimulates ovulation) with females of all other species.
a.
behavioral
b.
gametic
c.
habitat
d.
temporal
e.
mechanical


____ 141.   Dog breeders maintain the purity of breeds by keeping dogs of different breeds apart when they are fertile. This kind of isolation is most similar to which of the following reproductive isolating mechanisms?
a.
reduced hybrid fertility
b.
hybrid breakdown
c.
mechanical isolation
d.
habitat isolation
e.
gametic isolation


____ 142.   Rank the following from most general to most specific:
1.
gametic isolation
2.
reproductive isolating mechanism
3.
pollen-stigma incompatibility
4.
prezygotic isolating mechanism

a.
2, 3, 1, 4
b.
2, 4, 1, 3
c.
4, 1, 2, 3
d.
4, 2, 1, 3
e.
2, 1, 4, 3


____ 143.   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.
the postzygotic barrier called hybrid inviability
b.
the postzygotic barrier called hybrid breakdown
c.
the prezygotic barrier called hybrid sterility
d.
gametic isolation
e.
adaptation


____ 144.   Theoretically, the production of sterile mules by interbreeding between female horses and male donkeys should
a.
result in the extinction of one of the two parental species.
b.
cause convergent evolution.
c.
strengthen postzygotic barriers between horses and donkeys.
d.
weaken the intrinsic reproductive barriers between horses and donkeys.
e.
eventually result in the formation of a single species from the two parental species.


____ 145.   The biological species concept is inadequate for grouping
a.
plants.
b.
parasites.
c.
asexual organisms.
d.
animals that migrate.
e.
sympatric populations.


____ 146.   Which example below will most likely guarantee that two closely related species will persist only as distinct biological species?
a.
colonization of new habitats
b.
convergent evolution
c.
hybridization
d.
geographic isolation from one another
e.
reproductive isolation from one another


____ 147.   Races of humans are unlikely to evolve extensive differences in the future for which of the following reasons?
I.
The environment is unlikely to change.
II.
Human evolution is complete.
III.
The human races are incompletely isolated.

a.
I only
b.
III only
c.
I and II only
d.
II and III only
e.
I, II, and III


____ 148.   In a hypothetical situation, a certain species of flea feeds only on pronghorn antelopes. In rangelands of the western United States, pronghorns and cattle often associate with one another. If some of these fleas develop a strong preference, instead, for cattle blood and mate only with fleas that, likewise, prefer cattle blood, then over time which of these should occur, if the host mammal can be considered as the fleas' habitat?
1.
reproductive isolation
2.
sympatric speciation
3.
habitat isolation
4.
prezygotic barriers

a.
1 only
b.
2 and 3
c.
1, 2, and 3
d.
2, 3, and 4
e.
1 through 4


____ 149.   A defining characteristic of allopatric speciation is
a.
the appearance of new species in the midst of old ones.
b.
asexually reproducing populations.
c.
geographic isolation.
d.
artificial selection.
e.
large populations.


____ 150.   A rapid method of speciation that has been important in the history of flowering plants is
a.
genetic drift.
b.
a mutation in the gene controlling the timing of flowering.
c.
behavioral isolation.
d.
polyploidy.


____ 151.   Two closely related populations of mice have been separated for many generations by a river. Climatic change causes the river to dry up, thereby bringing the mice populations back into contact in a zone of overlap. Which of the following is not a possible outcome when they meet?
a.
They interbreed freely and produce fertile hybrid offspring.
b.
They no longer attempt to interbreed.
c.
They interbreed in the region of overlap, producing an inferior hybrid. Subsequent interbreeding between inferior hybrids produces progressively superior hybrids over several generations.
d.
They remain separate in the extremes of their ranges but develop a persistent hybrid zone in the area of overlap.
e.
They interbreed in the region of overlap, but produce sterile offspring.


____ 152.   The difference between geographic isolation and habitat differentiation is the
a.
relative locations of two populations as speciation occurs.
b.
speed (tempo) at which two populations undergo speciation.
c.
amount of genetic variation that occurs among two gene pools as speciation occurs.
d.
identity of the phylogenetic kingdom or domain in which these phenomena occur.
e.
the ploidy of the two populations as speciation occurs.


____ 153.   Among known plant species, which of these have been the two most commonly occurring phenomena leading to the origin of new species?
1. allopatric speciation
2. sympatric speciation
3. sexual selection
4. polyploidy
a.
1 and 3
b.
1 and 4
c.
2 and 3
d.
2 and 4


____ 154.   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. What kind of speciation has occurred in this example, and what has driven it?
a.
allopatric speciation, ecological isolation
b.
sympatric speciation, habitat differentiation
c.
allopatric speciation, behavioral isolation
d.
sympatric speciation, sexual selection
e.
sympatric speciation, allopolyploidy


____ 155.   The origin of a new plant species by hybridization, coupled with accidents during nuclear division, is an example of
a.
allopatric speciation.
b.
sympatric speciation.
c.
autopolyploidy.
d.
habitat selection.


____ 156.   The phenomenon of fusion is likely to occur when, after a period of geographic isolation, two populations meet again and
a.
their chromosomes are no longer homologous enough to permit meiosis.
b.
a constant number of viable, fertile hybrids is produced over the course of generations.
c.
the hybrid zone is inhospitable to hybrid survival.
d.
an increasing number of viable, fertile hybrids is produced over the course of generations
e.
a decreasing number of viable, fertile hybrids is produced over the course of generations.


____ 157.   The constantly changing nature of the Appalachian ground crickets (Allonemobius fasciatus and Allonemobius socius) hybrid zone favors
a.
no gene flow between the two gene pools.
b.
little gene flow between the two gene pools.
c.
increased levels of gene flow between the two gene pools.
d.
extinction of both species as the hybrids persist.


____ 158.   A hybrid zone is properly defined as
a.
an area where two closely related species' ranges overlap.
b.
an area where mating occurs between members of two closely related species, producing viable offspring.
c.
a zone that features a gradual change in species composition where two neighboring ecosystems border each other.
d.
a zone that includes the intermediate portion of a cline.
e.
an area where members of two closely related species intermingle, but experience no gene flow.


____ 159.   Which of these should decline in hybrid zones where reinforcement is occurring?
a.
gene flow between distinct gene pools
b.
speciation
c.
the genetic distinctness of two gene pools
d.
mutation rate
e.
hybrid sterility


____ 160.   The most likely explanation for the high rate of sympatric speciation that apparently existed among the cichlids of Lake Victoria in the past is
a.
sexual selection.
b.
habitat differentiation.
c.
polyploidy.
d.
pollution.
e.
introduction of a new predator.


____ 161.   The most likely explanation for the recent decline in cichlid species diversity in Lake Victoria is
a.
reinforcement.
b.
fusion.
c.
stability.
d.
geographic isolation.
e.
polyploidy.


____ 162.   In the narrow hybrid zone that separates the toad species Bombina bombina and Bombina variegata, what is true of those alleles that are unique to the parental species?
a.
Such alleles should be absent.
b.
Their allele frequency should be nearly the same as the allele frequencies in toad populations distant from the hybrid zone.
c.
The alleles' heterozygosity should be higher among the hybrid toads there.
d.
Their allele frequency on one edge of the hybrid zone should roughly equal their frequency on the opposite edge of the hybrid zone.


The following questions refer to the description below.

On the volcanic, equatorial West African island of Sao Tomé, two species of fruit fly exist. Drosophila yakuba inhabits the island's lowlands, and is also found on the African mainland, located about 200 miles away. At higher elevations, and found only on Sao Tomé, is found the very closely related Drosophila santomea. The two species can hybridize, though male hybrids are sterile. A hybrid zone exists at middle elevations, though hybrids there are greatly outnumbered by D. santomea. Studies of the two species' nuclear genomes reveal that D. yakuba on the island is more closely related to mainland D. yakuba than to D. santomea (2n=4 in both species). Sao Tomé rose from the Atlantic Ocean about 14 million years ago.

____ 163.   Which of these reduces gene flow between the gene pools of the two species on Sao Tomé, despite the existence of hybrids?
a.
hybrid breakdown
b.
hybrid inviability
c.
hybrid sterility
d.
temporal isolation
e.
a geographic barrier


____ 164.   The observation that island D. yakuba are more closely related to mainland D. yakuba than island D. yakuba are to D. santomea is best explained by proposing that D. santomea
a.
descended from a now-extinct, non-African fruit fly.
b.
arose de novo; that is, had no ancestors.
c.
descended from a single colony of D. yakuba, which had been introduced from elsewhere, with no subsequent colonization events.
d.
descended from an original colony of D. yakuba, of which there are no surviving members. The current island D. yakuba represent a second colonization event from elsewhere.


____ 165.   If a speciation event occurred on Sao Tomé, producing D. santomea from a parent colony of D. yakuba, then which terms apply?
I.
macroevolution
II.
allopatric speciation
III.
sympatric speciation

a.
I only
b.
II only
c.
I & II
d.
I & III


____ 166.   Using only the information provided in the paragraph, which of these is the best initial hypothesis for how D. santomea descended from D. yakuba?
a.
geographic isolation
b.
autopolyploidy
c.
habitat differentiation
d.
sexual selection
e.
allopolyploidy


____ 167.   Which of these evolutionary trees represents the situation described in the paragraph above (NOTE: yakuba (I) represents the island population, and yakuba (M) represents the mainland population)?
a.
b.
c.
d.


____ 168.   If the low number of hybrid flies in the hybrid zone, relative to the number of D. santomea flies there, is due to the fact that hybrids are poorly adapted to conditions in the hybrid zone, and if fewer hybrid flies are produced with the passage of time, this is most likely to lead to
a.
fusion.
b.
reinforcement.
c.
stability.
d.
further speciation events.


The following questions refer to the paragraph and graphs below.

In a hypothetical situation, the National Park Service, which administers Grand Canyon National Park in Arizona, builds a footbridge over the Colorado River at the bottom of the canyon. The footbridge permits interspersal of two closely related antelope squirrels. Previously, one type of squirrel had been restricted to the terrain south of the river, and the other type had been restricted to terrain on the north side of the river. Immediately before and ten years after the bridge's completion, ten antelope squirrels from both sides of the river were collected, blood samples were taken, and frequencies of alleles unique to the two types of antelope squirrels were determined (see graphs below).



____ 169.   The data in the graphs above indicate that
a.
a hybrid zone was established after the completion of the bridge.
b.
no interspersal of the two types of squirrel occurred after the completion of the bridge.
c.
gene flow occurred from one type of squirrel into the gene pool of the other type of squirrel.
d.
2-way migration of squirrels occurred across the bridge, but without hybridization.
e.
some northern squirrels migrated south, but no southern squirrels migrated north across the bridge.


____ 170.   The results depicted in the graphs above are best accounted for by which of the following facts?
a.
The Colorado River has been an effective geographic barrier to these two types of squirrels for several million years.
b.
There is more white fur on the tails of the northern squirrels than on the tails of the southern squirrels.
c.
Both types of squirrel subsist largely on a diet of pine nuts and juniper seeds in this ecosystem.
d.
Both types of squirrel share the same common ancestor.
e.
Both types of squirrel are active during the day.


____ 171.   According to the concept of punctuated equilibrium, the "sudden" appearance of a new species in the fossil record means that
a.
the species is now extinct.
b.
speciation occurred instantaneously.
c.
speciation occurred in one generation.
d.
speciation occurred rapidly in geologic time.
e.
the species will consequently have a relatively short existence, compared with other species.


____ 172.   According to the concept of punctuated equilibrium,
a.
natural selection is unimportant as a mechanism of evolution.
b.
given enough time, most existing species will branch gradually into new species.
c.
a new species accumulates most of its unique features as it comes into existence.
d.
evolution of new species features long periods during which changes are occurring, interspersed with short periods of equilibrium, or stasis.
e.
transitional fossils, intermediate between newer species and their parent species, should be abundant.


____ 173.   Which of the following would be a position held by an adherent of the punctuated equilibrium theory?
a.
A new species forms most of its unique features as it comes into existence and then changes little for the duration of its existence.
b.
One should expect to find many transitional fossils left by organisms in the process of forming new species.
c.
Given enough time, most existing species will gradually evolve into new species.
d.
Natural selection is unimportant as a mechanism of evolution.


____ 174.   Speciation
a.
occurs at such a slow pace that no one has ever observed the emergence of new species.
b.
occurs only by the accumulation of genetic change over vast expanses of time.
c.
must begin with the geographic isolation of a small, frontier population.
d.
proceeds at a uniform tempo across all taxa.
e.
can involve changes involving a single gene.


____ 175.   Which of the following statements about speciation is correct?
a.
The goal of natural selection is speciation.
b.
When reunited, two allopatric populations will not interbreed.
c.
Natural selection chooses the reproductive barriers for populations.
d.
Prezygotic reproductive barriers usually evolve before postzygotic barriers.
e.
Speciation is a basis for understanding macroevolution.


____ 176.   Upon undergoing change, which of these genes is most likely to result in speciation while a geographic barrier separates two populations of a flowering-plant species?
a.
one that affects the rate of chlorophyll a synthesis
b.
one that affects the amount of growth hormone synthesized per unit time
c.
one that affects the compatibility of male pollen and female reproductive parts
d.
one that affects the average depth to which roots grow down through the soil
e.
one that affects how flexible the stems are


____ 177.   In order for speciation to occur, what is true?
a.
The number of chromosomes in the genome must change.
b.
Changes to centromere location or chromosome size must occur within the genome.
c.
Large numbers of genes that affect a single phenotypic trait must change.
d.
Large numbers of genes that affect numerous phenotypic traits must change.
e.
At least one gene, affecting at least one phenotypic trait, must change.


The following questions refer to the evolutionary tree below, whose horizontal axis represents time (present time is on the far right) and whose vertical axis represents morphological change.


Figure 24.1

____ 178.   Which of these five species (V—Z) in the evolutionary tree would likely have fossil records indicating that punctuated equilibrium was an important part of their evolutionary history?
a.
V and W
b.
V and Y
c.
X and Y
d.
W, Y, and Z
e.
X, Y, and Z


____ 179.   Which of these five species originated earliest and appeared suddenly in the fossil record?
a.
V
b.
W
c.
X
d.
Y
e.
Z


____ 180.   Which conclusion can be drawn from this evolutionary tree?
a.
Gradualistic speciation and speciation involving punctuated equilibrium are mutually exclusive concepts; only one of them can occur.
b.
Eldredge and Gould would deny that the lineages labeled X, Y, and Z could represent true species.
c.
Assuming that the tip of each line represents a species, there are five extant (i.e., not extinct) species resulting from the earliest common ancestor.
d.
A single clade (i.e., a group of species that share a common ancestor) can exhibit both gradualism and punctuated equilibrium.
e.
V and W shared a common ancestor more recently than any of the other species.


____ 181.   Which of these five species is the extant (i.e., not extinct) species that is most closely related to species X, and why is this so?
a.
V; shared a common ancestor with X most recently
b.
W; shared a common ancestor with X most recently
c.
Y; arose in the same fashion (i.e., at the same tempo) as X
d.
Z; shared a common ancestor with X most recently, and arose in the same fashion as X
e.
This tree does not provide enough information to answer this question.


____ 182.   The largest unit within which gene flow can readily occur is a
a.
population.
b.
species.
c.
genus.
d.
hybrid.
e.
phylum.


____ 183.   Bird guides once listed the myrtle warbler and Audubon's warbler as distinct species. Recently, these birds have been classified as eastern and western forms of a single species, the yellow-rumped warbler. Which of the following pieces of evidence, if true, would be cause for this reclassification?
a.
The two forms interbreed often in nature, and their offspring have good survival and reproduction.
b.
The two forms live in similar habitats.
c.
The two forms have many genes in common.
d.
The two forms have similar food requirements.
e.
The two forms are very similar in coloration.


____ 184.   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.
habitat isolation
b.
temporal isolation
c.
behavioral isolation
d.
gametic isolation
e.
postzygotic barriers


____ 185.   Which of the following factors would not contribute to allopatric speciation?
a.
A population becomes geographically isolated from the parent population.
b.
The separated population is small, and genetic drift occurs.
c.
The isolated population is exposed to different selection pressures than the ancestral population.
d.
Different mutations begin to distinguish the gene pools of the separated populations.
e.
Gene flow between the two populations is extensive.


____ 186.   Plant species A has a diploid number of 12. Plant species B has a diploid number of 16. A new species, C, arises as an allopolyploid from A and B. The diploid number for species C would probably be
a.
12.
b.
14.
c.
16.
d.
28.
e.
56.


____ 187.   According to the punctuated equilibria model,
a.
natural selection is unimportant as a mechanism of evolution.
b.
given enough time, most existing species will branch gradually into new species.
c.
most new species accumulate their unique features relatively rapidly as they come into existence, then change little for the rest of their duration as a species.
d.
most evolution occurs in sympatric populations.
e.
speciation is usually due to a single mutation.


Short Answer

         188.   Which stratum should contain the greatest proportion of extinct organisms?

         189.   If "x" indicates the location of fossils of two closely related species, then fossils of their most-recent common ancestor are most likely to occur in which stratum?

         190.   Blue light is that portion of the visible spectrum that penetrates the deepest into bodies of water. Ultraviolet (UV) light, though, can penetrate even deeper. A gene within a population of marine fish that inhabits depths from 500 m to 1,000 m has an allele for a photopigment that is sensitive to UV light, and another allele for a photopigment that is sensitive to blue light. Which graph below best depicts the predicted distribution of these alleles if the fish that carry these alleles prefer to locate themselves where they can see best?




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