Download Evolution Exam - Multiple Choice and Free Response Question

Evolution Exam Practice Questions
_____1. During the 1950s, a scientist named Lysenko tried to solve the food shortages in the Soviet Union by
breeding wheat that could grow in Siberia. He theorized that if individual wheat plants were exposed to cold,
they would develop additional cold tolerance and pass it to their offspring. Based on the ideas of artificial and
natural selection, do you think this project worked as planned?
A) Yes, the wheat probably evolved better cold tolerance over time through inheritance of acquired
characteristics.
B) No, because Lysenko took his wheat seeds straight to Siberia instead of exposing them incrementally to cold.
C) No, because there was no process of selection based on inherited traits. Lysenko assumed that exposure
could induce a plant to develop additional cold tolerance and that this tolerance would be passed to the plant's
offspring.
D) Yes, because this is generally the method used by plant breeders to develop new crops.
_____2. Which of the following best expresses the concept of natural selection?
A) differential reproductive success based on inherited characteristics
B) inheritance of acquired characteristics
C) change in response to need
D) a process of constant improvement, leading eventually to perfection
_____3. A dog breeder wishes to develop a breed that does not bark. She starts with a diverse mixture of dogs.
Generation after generation, she allows only the quietest dogs to breed. After 30 years of work she has a new
breed of dog with interesting traits, but on average, the dogs still bark at about the same rate as other dog
breeds. Which of the following would be a logical explanation for her failure?
A) There is no variation for the trait (barking).
B) The tendency to bark is not a heritable trait.
C) The selection was artificial, not natural, so it did not produce evolutionary change.
D) There was no selection (differential reproductive success) related to barking behavior.
_____4. Which of the following statements regarding the currently available fossil record is false?
A) The currently available fossil record shows that the earliest fossils of life are about 3.5 billion years old.
B) The currently available fossil record shows that younger strata were laid down on top of older strata.
C) The currently available fossil record documents gradual evolutionary changes that link one group of
organisms to another.
D) The currently available fossil record shows that the first life forms were eukaryotes.
_____5. Humans share several features with salamanders. Certain genes and proteins are nearly identical
between the two species; both species have four limbs with a similar skeletal structure; the species' early
embryos are very similar; and where the salamander has a functional tail, humans have a vestigial tailbone. In
evolutionary terms, these are examples of
A) biogeographic similarity.
B) homology.
C) adaptation by natural selection.
D) coincidental similarity.
_____6. Microevolution, or evolution at its smallest scale, occurs when
A) an individual's traits change in response to environmental factors.
B) a community of organisms changes due to the extinction of several dominant species.
C) a new species arises from an existing species.
D) a population's allele frequencies change over a span of generations.
_____7. The ultimate source of all new alleles is
A) mutation.
B) chromosomal duplication.
C) genetic drift.
D) natural selection.
_____8. A population of 1,000 birds exists on a small Pacific island. Some of the birds are yellow, a
characteristic determined by a recessive allele. The others are green, a characteristic determined by a dominant
allele. A hurricane on the island kills most of the birds from this population. Only ten remain, and those birds all
have yellow feathers. Which of the following statements is true?
A) Assuming that no new birds come to the island and no mutations occur, future generations of this population
will contain both green and yellow birds.
B) The hurricane has caused a population bottleneck and a loss of genetic diversity.
C) This situation illustrates the effect of a mutation event.
D) The ten remaining birds will mate only with each other, and this will contribute to gene flow in the
_____9. Thirty people are selected for a long-term mission to colonize a planet many light years away from
Earth. The mission is successful and the population rapidly grows to several hundred individuals. However,
certain genetic diseases are unusually common in this group, and their gene pool is quite different from that of
the Earth population they have left behind. Which of the following phenomena has left its mark on this
population?
A) founder effect
B) bottleneck effect
C) high rates of mutation
D) natural selection
_____10. A woman struggling with a bacterial illness is prescribed a month's supply of a potent antibiotic. She
takes the antibiotic for about two weeks and feels much better. Should she save the remaining two-week supply,
or should she continue taking the drug?
A) She should save the drug for later, because if she keeps taking it the bacteria will evolve resistance.
B) She should save the drug for use the next time the illness strikes.
C) She should save the drug because antibiotics are in short supply and she may need it to defend herself against
a bioterrorism incident.
D) She should continue taking the drug until her immune system can completely eliminate the infection.
Otherwise the remaining bacteria in her system may recover, and they will probably be resistant.
_____11. The sickle-cell allele produces a serious blood disease in homozygotes. Why doesn't natural selection
eliminate this allele from all human populations?
A) Natural selection is a positive force, so it does not eliminate alleles.
B) In populations where endemic malaria is present, heterozygotes have an important advantage: They are
resistant to malaria and therefore are more likely to survive and produce offspring that carry the allele.
C) Mutations keep bringing the allele back into circulation.
D) Natural selection occurs very slowly, but elimination of the sickle-cell allele is expected to occur soon.
_____12. Speciation, or the formation of new species, is
A) a form of microevolution.
B) responsible for the diversity of life.
C) necessary for natural selection and adaptation.
D) an event that has occurred only a few times in the history of the planet.
_____13. Genetic drift as an evolutionary factor is
A) greater in a population with small numbers than a population with large numbers.
B) greater in a population with much genetic variation than in a population with little genetic variation.
C) responsible for the selection of mutations.
D) connected to the movements of alleles between populations of a single species.
_____ 14. The “RNA world hypothesis” poses that RNA may have functioned as the first genetic material in
early protobionts. Scientists point to three characteristics of RNA that support the “RNA world hypothesis” with
evidence. Which of the following is NOT one of these characteristics of RNA?
A) RNA in modern cells can sometimes act as ribozymes and show catalytic activity, increasing the rate of
certain chemical reactions.
B) Modern cells use an RNA template when synthesizing proteins.
C) A single strand of RNA can temporarily bind to complementary RNA monomers, and produce a second
strand, with a predictable sequence of nucleotide bases.
D) In modern cells, RNA provides the template on which DNA nucleotides are assembled.
_____15. Which of the following statements regarding the definition of species is false?
A) The ecological species concept identifies species in terms of their ecological niches.
B) The phylogenetic species concept defines a species as a set of organisms that shares a common ancestor and
forms one branch on the tree of life.
C) The morphological species concept relies upon comparing the DNA sequences of organisms.
D) Under the biological species concept, the gap between species is maintained by reproductive isolation.
_____16. Which of the following types of reproductive barriers separates a pair of species that could interbreed
except that one mates at dusk and the other at dawn?
A) temporal isolation
B) habitat isolation
C) behavioral isolation
D) mechanical isolation
_____17. The deer mouse is the most widely distributed small mammal in North America. It varies widely
greatly according to its geographical location, especially in coat color, tail length, and foot length. Where would
you expect deer mice to be relatively uniform?
A) In mountainous areas, where environmental conditions change dramatically from place to place.
B) On islands, where populations are isolated.
C) Over large areas where there is little topographical or vegetational change.
D) In regions between forests and deserts, where there is significant vegetational change.
_____18. Two species interbreed occasionally and produce vigorous, fertile hybrids. When the hybrids breed
with each other or with either parent species, however, the offspring are feeble or sterile. These species are
separated by
A) gametic isolation.
B) reduced hybrid fertility.
C) reduced hybrid viability.
D) hybrid breakdown.
_____19. In which of the following situations would speciation be most likely to occur?
A) A population of juniper shrubs is split in two by a canyon. Every year, strong winds carry a small amount of
the shrub's pollen across the canyon.
B) A Japanese mollusk species whose larvae are often carried from port to port in ship bilge water now
flourishes in San Francisco Bay, a busy commercial port.
C) Bighorn sheep occupy mountains from Canada through Death Valley in Southern California, interbreeding
all the way. The populations at the two ends of the range live in very different environments.
D) Seven monkeys escape from an amusement park and zoo in South Florida. To everyone's surprise, they
establish a small but viable population, coexisting successfully with humans in a partly suburban
environment very different from their native African habitat.
_____20. Diane Dodd raised different fruit fly populations on different food sources. She found that after about
40 generations, the evolution of reproductive isolation was under way. The mechanism of evolution responsible
for this was
A) natural selection.
B) genetic drift.
C) gene flow.
D) mutation.
_____21. Sympatric speciation commonly occurs through ________ in plants, but is more likely to occur
through ________ in animals.
A) polyploidy . . . habitat differentiation and sexual selection
B) habitat differentiation and sexual selection . . . polyploidy
C) asexual reproduction . . . chromosome duplications
D) self-pollination . . . polyploidy and other genetic mechanisms
_____22. Which of the following statements about the Galápagos finches is false?
A) The Galápagos finch species differ in their feeding habitats.
B) Each island in the Galápagos chain has one and only one isolated, unique species of Darwin's finch.
C) Most speciation events of the Galápagos finches occurred when some finches made it to another island,
evolved in isolation, and accumulated enough changes to become a new species.
D) The evolution of the Galápagos finches is an excellent example of adaptive radiation.
_____23. One of the finest available sequences of fossils shows how horses have changed slowly and by subtle
steps from small shrub-browsing ancestors to the large, grass-grazing modern horse. A large number of fossil
species have been named, and it is often difficult to decide on the identity of a fossil horse because transitional
forms are common. This record of evolution best fits the idea of
A) the gradual model of speciation.
B) punctuated equilibrium.
C) adaptive radiation.
D) hybrid breakdown.
Base your answers to questions 24 and 25 on the paragraphs below and your knowledge of biology.
In 2004, scientists announced the discovery of the fossil remains of some extremely short early humans on the
Indonesian island of Flores. The new species has been named Homo floresiensis. One hypothesis is that H.
floresiensis evolved from Homo erectus, another early human species. How did a population of H. erectus
become isolated on this remote island? Early humans constructed boats and rafts, so perhaps they were blown
far off course by strong winds during a storm.
H. erectus averaged almost 6 feet in height, but the remains show that adults of H. floresiensis were only about
3 feet tall. It's hypothesized that limited resources on this hot and humid island (only 31 square miles) exerted
selection pressure and succeeding generations began to shrink in size. Small bodies require less food, use less
energy, and are easier to cool than larger bodies. Evolution of small size in similar circumstances has been
observed in many other species, but never before in humans. This find demonstrates that evolutionary forces
operate on humans in the same way as on all other organisms.
_____24. The evolution of Homo floresiensis is an example of
A) sympatric speciation.
B) allopatric speciation.
C) adaptive radiation.
D) hybridization.
_____25. If H. floresiensis were reunited with H. erectus at a much later date, but the two populations could no
longer interbreed, it would be correct to conclude that H. floresiensis
A) is no longer fertile as a species.
B) had been isolated for more than 50,000 years.
C) has become less fit than H. erectus.
D) had evolved reproductive barriers.
_____26. Geological evidence indicates that two land masses became separated by a deep ocean channel 45
million years ago and have been moving apart ever since. You are studying a group of organisms that is
widespread as a native part of the biota on both of the land masses. What can you conclude about the group's
evolutionary history?
A) The group's ancestors were definitely present on the original land mass before it broke up.
B) The group's ancestors cannot have been present on the original land mass before it broke up.
C) It depends on the dispersal abilities of the organism. If the organism cannot move across the open ocean, it is
very likely that the group's ancestors were present on the original land mass before it broke up.
D) The group's ancestors must have independently colonized each of the land masses from a third location
within the past 45 million years.
Base your answers to questions 27-31 on the reading below and your knowledge of Biology.
Guppies are small fish found in streams in Venezuela. Male guppies are brightly colored, with black, red, blue
and iridescent (reflective) spots. Males cannot be too brightly colored or they will be seen and consumed by
predators, but if they are too plain, females will choose other males. Natural selection and sexual selection push
in opposite directions. When a guppy population lives in a stream in the absence of predators, the proportion of
males that are bright and flashy increases in the population. If a few aggressive predators are added to the same
stream, the proportion of brightly-colored males decreases with about 5 months (3-4 generations). The effects of
predators on guppy coloration have been studied artificial ponds with mild, aggressive, and no predators, and by
similar manipulations of predators in natural stream environments (Endler, 1980). For each of the following
questions, choose the one answer that best reflects how an evolutionary biologist would answer.
_____27. A typical natural population of guppies consists of hundreds of guppies. Which statement best
describes the guppies of a single species in an isolated population?
A) The guppies share all of the same characteristics and are identical to one another.
B) The guppies share all of the essential characteristics of the species; the minor variations they display don’t
affect survival.
C) The guppies are all identical on the inside, but have many differences in appearance.
D) The guppies share many essential characteristics, but also vary in many features.
_____28. Fitness is a term often used by biologists to explain the evolutionary success of certain organisms.
Which feature would a biologist consider to be most important in determining which guppies re “most fit?”
A) Large body size and ability to swim quickly away from predators.
B) Excellent ability to compete for food.
C) High number of offspring that survive to reproductive age.
D) High number of matings with many different females.
_____29. Assuming ideal conditions with abundant food, space, and no predators, what would happen if a pair
of guppies were placed in a large pond?
A) The guppy population would grow slowly, as guppies would have only the number of babies that are needed
to replenish the population.
B) The guppy population would grow slowly at first, then would grow rapidly, and thousands of guppies would
fill the pond.
C) The guppy population would never become very large, because only organisms such as insects and bacteria
reproduce in that manner.
D) The guppy population would continue to grow slowly over time.
_____30. If there are many predators in the pond, why is it that brightly colored guppies continue to exist in the
population?
a. Brightly colored guppies swim faster than dull colored ones, and therefore are more fit.
b. Females prefer brightly colored male guppies to dull colored ones.
c. This is just a temporary situation; Brightly colored guppies will go extinct over time.
d. Guppies begin life as brightly colored and then gradually change to be dull colored.
_____31. In guppy populations, what are the primary changes that occur gradually over time?
A) The traits of each individual guppy within a population gradually change.
B) The proportions of guppies having different traits within a population changes.
C) Successful behaviors learned by certain guppies are passed to offspring.
D) Mutations occur to meet the needs of the guppies as the environment changes.
_____32. Over a span of several thousand years, a number of species show adaptations to climate change: drier,
warmer conditions select for succulent vegetation and deep taproots in plants, burrowing in mammals and
amphibians, and other similar adaptive changes. What will happen if the climate shifts in the opposite direction
and becomes progressively wetter and cooler?
A) Ongoing processes of adaptation will continue because of evolutionary inertia.
B) Different adaptive trends will probably be favored in the new climatic environment.
C) Current adaptive trends will continue but organisms will now also have to add on adaptations to deal with
cool, wet conditions.
D) Adaptation will cease because cool, wet conditions are generally favorable for life.
_____33. Which of the following options lists taxonomic categories in the correct order from most specific to
most general?
A) genus, family, class, order, phylum
B) genus, family, order, class, phylum
C) family, genus, order, phylum, class
D) family, genus, class, order, phylum
_____34. A systematist includes a lizard in a phylogenetic analysis of relationships among bird families. In this
analysis, the lizard would be treated as
A) the ingroup.
B) the outgroup.
C) a derived group.
D) an analogous group.
_____35. Which of the following options lists major events in the history of life on Earth in the proper order,
from earliest to most recent?
A) first prokaryotes; photosynthesis; colonization of land by plants and fungi; first eukaryotes
B) first eukaryotes; photosynthesis; colonization of land by plants and fungi; first prokaryotes
C) first prokaryotes; first eukaryotes; photosynthesis; colonization of land by plants and fungi
D) first prokaryotes; photosynthesis; first eukaryotes; colonization of land by plants and fungi
_____36. Trout in stream A and trout in stream B look similar, but not quite identical. Scientists were unsure if
they were two populations of one fish species, or two separate species. To figure this out, they studied the life
cycle, habitat, and reproduction of the trout. In a year with a typical amount of rainfall, the trout stay within
their own stream and mate with individuals that live nearby. However, in years that include excessive rainfall
and flooding, the fish are washed downstream to a larger river, and must swim back up into either stream A or
stream B. They choose which stream to swim up randomly, often ending up in a different location than where
they themselves were born. When a trout that originated from stream A does breed with a trout from stream B,
their offspring are healthy and show no decrease in fertility. Scientists think that flooding in this watershed is
happening more and more frequently, due to global climate change. Given this information, predict what is the
most likely result for trout A and trout B.
A) they will become reproductive isolated from each other
B) they will become more similar in their gene pools
C) they will go through random changes due to genetic drift
D) they will adapt to different conditions and look more and more different
_____37. Two species that occasionally mate and produce zygotes, but which have incompatible genes that
prevent the resulting embryo from developing, are separated by
A) gametic isolation.
B) reduced hybrid fertility.
C) reduced hybrid viability.
D) hybrid breakdown.
_____38. Which of the following types of reproductive barriers separates a pair of insect species that could
interbreed except that one lives on goldenrod plants and the other on autumn daisies in the same general area?
A) temporal isolation
B) habitat isolation
C) behavioral isolation
D) gametic isolation
Part V. Free Response Question:
Phylogeny is the evolutionary history of a species.
1.
(a) The evolution of a species is dependent on changes in the genome of the species. Identify
TWO mechanisms of genetic change, and explain how each affects genetic variation.
2.
(b) Based on the data in the table below, draw a phylogenetic tree that reflects the evolutionary
relationships of the organisms based on the differences in their cytochrome c amino-acid sequences and
explain the relationships of the organisms. Based on the data, identify which organism is most closely
related to the chicken and explain your choice.
3.
(c) Describe TWO types of evidence—other than the comparison of proteins—that can be used to
determine the phylogeny of organisms. Discuss one strength of each type of evidence you described.
THE NUMBER OF AMINO ACID DIFFERENCES IN CYTOCHROME c AMONG VARIOUS
ORGANISMS