Download Unit 6 Practice Test

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In Darwin’s view of descent with modification _____.
a. An organism’s traits only affect its own survival
b. Natural selection can improve the match between an organism and its environment
c. Individuals can evolve
d. Environmental changes have no effect on the organisms living in that environment
The smallest unit that can evolve in a(n) _____.
a. Species
b. Genotype
c. Individual
d. Population
Vestigial organs are _____.
a. Remnants of structures that were useful to an organism’s ancestors
b. One piece of evidence that does not support the theory of evolution
c. Examples of anatomical imperfections such as the human knee
d. Homologies that can only be observed in embryos
To describe evolution as a “scientific theory” means that _____.
a. It is not factual
b. It is a matter of opinion
c. It is a broad model that is supported by many observations and much experimental
evidence
d. It can be considered dogma
In the context of populations, how do we define evolution?
a. Evolution is a change in a population’s allelic frequencies over generations
b. Evolution is the tendency for some individuals in a populations to leave more offspring
than others
c. Evolution is the way in which sexual reproduction can rapidly spread advantageous
traits throughout the population
d. Evolution is always caused by natural selection
In the Hardy-Weinberg equation, p2 represents _____.
a. The total alleles in the gene pool
b. The frequency of heterozygous dominant individuals in the population
c. The frequency of homozygous recessive individuals in the population
d. The expected frequency of homozygous dominant individuals in the population
In a large population of bonobos, the frequency of the recessive allele is initially 0.1. What is the
frequency of the dominant allele? Assume that there are two alleles of this gene.
a. 10%
b. 20%
c. 50%
d. 90%
In a population in Hardy-Weinberg equilibrium, 1% of the individuals in a population show the
recessive trait of a certain characteristic. In this situation, what is the value of p?
a. 99%
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b. 0.81
c. 0.9
d. 0.18
In a certain group of African people, 4% are born with sickle-cell disease (homozygous
recessive). If this group is in Hardy-Weinberg equilibrium, what percentage of the group has the
selective advantage of being more resistant to malaria (heterozygous) than those individuals
who are homozygous for normal hemoglobin or for sickle-cell disease?
a. 4%
b. 8%
c. 16%
d. 32%
Which of the following sets of conditions is required for Hardy-Weinberg equilibrium?
a. A large population, no mutations, and natural selection
b. A large population, random mutations, and no migrations of alleles in or out
c. No mutations, sexual selection, and no natural selection
d. Random mating, no natural selection, and a large population
A population of 15 birds inhabits a fairly new island. Ten of the birds are dark brown and five of
them are light brown. By chance, two of the dark brown birds and three of the light brown birds
die before producing any offspring. All of the birds in the next generation are dark brown. This
change in phenotypic frequency can be attributed to _____.
a. Natural selection
b. Genetic drift
c. Gene flow
d. Disruptive selection
An earthquake hits a small island. All but a small group of closely related lizards are eliminated,
and the survivors spread out over the island. This is an instance of _____.
a. Founder effect
b. Bottleneck effect
c. Gene flow
d. Nonrandom mating
Which of the following is the best example of gene flow?
a. A small population of humans colonizes a newly formed island
b. An earthquake results in the formation of a canyon, splitting a population of toads apart
c. Wind blows pollen from one population of plants to another and cross-fertilization
occurs
d. All the mutations in a population were neutral
A population of squirrels is preyed upon by small hawks. The smaller squirrels can escape into
burrows. The larger squirrels can fight off the hawks. After several generations, the squirrels in
the area tend to be very small or very large. What process is responsible for this outcome?
a. Stabilizing selection
b. Directional selection
c. Disruptive selection
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d. Balancing selection
Which one of the following conditions is necessary for speciation to occur?
a. Reproductive isolation
b. Sympatric speciation
c. Mass extinction
d. Interbreeding among neighboring populations
Prezygotic barriers _____.
a. Prevent fertilization of gametes from members of closely related species
b. Prevent a hybrid zygote from developing into a viable, fertile adult
c. Prevent fertilization from occurring between members of the same species with
incompatible genes
d. Prevent donkeys and horses from mating
Three species of frogs, Rana pipiens, Rana clamitans, and Rana sylvatica, all mate in the same
ponds, but they pair off correctly because they have different calls. This is a specific example of
a _____ barrier, called _____.
a. Prezygotic barrier; behavioral isolation
b. Postzygotic; hybrid breakdown
c. Prezygotic; temporal isolation
d. Postzygotic; mechanical isolation
Which of the following is an example of a postzygotic reproductive barrier?
a. One species of frog mates in April, another mates in May
b. Two fruit flies of different species produce sterile offspring
c. The sperm of a marine worm can only penetrate eggs of the same species
d. One species of flower grows in forested areas, another in meadows
The biological species concept emphasizes _____.
a. Molecular differences
b. The evolution of reproductive isolation
c. Common ancestry
d. Morphological and structural features
Which of the following organisms are most likely to be subject to allopatric speciation?
a. Whale populations of the same species located on opposite sides of the Atlantic Ocean
b. Pine trees in Alaska and pine trees on the island of Madagascar
c. Mountain lions in the canyons of Wyoming and in the canyons of Utah
d. Fruit flies on bananas and fruit flies on organs
In the case of the Lake Victoria cichlids, sympatric speciation has been shown to be driven by
_____.
a. Habitat differentiation
b. Mechanical isolation
c. Sexual selection
d. Post-zygotic barriers