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Chapter 16 Test
Name_____________________________________________________
_____1. Phenotypic traits often vary between two extremes, with most individuals having an average
version of the trait. This can be graphed as a
a. Punnet square
b. Bell curve
c. Straight line
d. Genotype frequency table
_____2. Variations in genotype arise by random fusion of gametes, mutation, and
a. Recombination
b. Translation
c. Transcription
d. Sorting by phenotype
_____3. The total genetic information in a population is called the
a. Allele frequency
b. Phenotype frequency
c. Gene pool
d. Distribution of traits
_____4. Saint Bernards and Chihuahuas (two breeds of domestic dogs) cannot mate normally owing to
great differences in size. . Thus, they are reproductively isolated to some extent. What type of isolating
mechanism is operating here?
a. Developmental
b. Prezygotic
c. Postzygotic
d. Geographic
_____5. If a population is in genetic equilibrium,
a. Evolution is occurring
b. Speciation is occurring
c. Allele frequencies change from one generation to the next
d. Allele frequencies remain the same from one generation to the next
_____6. Mutations affect genetic equilibrium by
a. Maintaining it
b. Introducing new alleles
c. Causing immigration
d. Causing emigration
_____7. Directional selection, disruptive selection, and stabilizing selection are all examples of
a. Genetic equilibrium
b. Natural selection
c. Mutation
d. Speciation
_____8. The most common way for new species to form is through
a. Mutation
b. Stabilizing selection
c. Geographic and reproductive isolation
d. Genetic equilibrium
_____9. The tendency for males to develop extreme versions of traits that appeal to females is a result
of
a. Random mating
b. Speciation
c. Reproductive isolation
d. Sexual selection
_____10. Genetic drift is most likely to occur in
a. Small populations
b. Large populations
c. Populations that have a low frequency of mutation
d. Populations that migrate
_____11. The smallest unit in which evolution occurs is
a. An individual organism
b. A species
c. A population
d. A kingdom
_____12. Length, weight, and many other quantitative traits in a population tend to show variation
that, when plotted on a graph, looks like
a. A population wave
b. A bell curve
c. A gene pool
d. An equilibrium plot
_____13. If a population of four o’clock flowers consists of five RR plants (red flowers), two Rr plants
(pink flowers), and one rr plant (white flowers), the phenotype frequency of plants with pink flowers is.
a. 0.125
b. 0.25
c. 0.5
d. 0.75
_____14. In the population described in question 14, the frequency of the R allele is
a. 0.125
b. 0.25
c. 0.5
d. 0.75
_____15. For a population to be in genetic equilibrium,
a. Individuals must not enter or leave the population
b. The population must be evolving
c. The population must be small
d. Selection must occur
_____16. Any violation of the conditions necessary for Hardy-Weinberg equilibrium can result in
a. Independent assortment
b. Evolution
c. Disorganizing selection
d. Eventual extinction
_____17. The movement of reproductive individuals from one population to another results in
a. Infertile offspring
b. Spontaneous mutation
c. Genetic drift
d. Gene flow
_____18. Genetic Drift is most likely to occur in
a. Small populations
b. Large populations
c. Populations that migrate
d. Populations that have a low frequency of mutation
_____19. Assortative mating occurs when
a. One animal mates with a variety of other individuals during its lifetime
b. Males choose to mate with females that are the most fertile
c. An individual chooses mates that are similar to itself
d. Females choose to mate with males that are from other populations
_____20. Starlings produce an average of five eggs in each clutch. If there are more than five, the
parents cannot adequately feed the young. If there are fewer than five, predators may destroy the
entire clutch. This is an example of
a. Disruptive selection
b. Directional selection
c. Stabilizing selection
d. Sexual selection
_____21. One limitation of the morphological species concept is that
a. Morphological characteristics are not easy to observe
b. It cannot be applied to extinct organisms
c. Members of different species often appear quite different
d. There can be morphological differences among individuals in a single population
_____22. According to the biological species concept, a species is a population of organisms that
a. Can successfully interbreed but cannot breed with other groups
b. Have a similar structure and appearance
c. Are physically separated from other organisms with a similar appearance
d. Can hybridize with each other to produce infertile offspring
_____23. Fish populations that do not interbreed because they live in different ponds may evolve into
separate species due to
a. Ecological isolation
b. Prezygotic isolation
c. Geographic isolation
d. Postzygotic isolation
_____24. Bird populations that do not interbreed because they cannot recognize each other’s mating
calls may evolve into separate species due to
a. Ecological isolation
b. Geographic isolation
c. Prezygotic isolation
d. Postzygotic isolation
_____25. A pattern of rapid evolutionary changes followed by long periods of no change is described as
a. Gradual evolution
b. Punctuated equilibrium
c. Reproductive isolation
d. Continuous speciation
_____26. Which of the following would not disrupt Hardy-Weinberg genetic equilibrium?
a. New individuals coming into the population
b. A stream forming in the middle of the population that isolates groups of the population
c. Random mating
d. A rare mutation
_____27. A population is made up of most bats that are brown; there are some that are white and
some that are black. The climate changes and snow is present. The white bats can blend in better and
are selected for by the environment. This is an example of what type of natural selection?
a. Disruptive Selection
b. Directional Selection
c. Stabilizing Selection
d. Bell Curve
+ true, o false
_____ 28. Genetic drift is the random change in allele frequency.
_____ 29. Natural Selection always eliminates any genetic disorders from a population, regardless of the
frequency of the gene that is responsible for it.
_____ 30. Punctuated equilibrium refers to the theory that evolution occurs slowly over a long period of
time.
_____ 31. Within a population, isolation leads to speciation.
_____32. A lake dries up and separates the lake into separate ponds that separate the fish populations
which demonstrates sexual selection.
_____ 33. Actual proportions of homozygotes and heterozygotes can differ from Hardy-Weinberg
predictions because of
a.
b.
c.
d.
the occurrence of mutations
nonrandom mating among individuals
genetic drift within the population
all of the above
_____ 34. The movement of alleles into or out of a population due to migration is called
a.
b.
c.
d.
mutation
gene flow
nonrandom mating
natural selection
_____ 35. The hypothesis that evolution occurs at a rapid rate, separated by periods of no change.
a.
b.
c.
d.
was supported by Darwin
is known as punctuated equilibrium
is supported by many transitional forms in the fossil record.
Was proposed by Lyell.
_____ 36. Natural selection shapes populations by
a.
b.
c.
d.
acting on genes
acting on recessive alleles.
Acting on phenotypes.
All of the above
_____ 37. The type of selection that may eliminate extremes of phenotypes is
a.
b.
c.
d.
directional selection
disruptive selection
polygenic selection
stabilizing selection
_____ 38. Directional selection is characteristic of
a.
b.
c.
d.
intermediate phenotypes
a way to increase the number of dominant alleles
individuals with an extreme trait.
None of the above
39. What five assumptions must be made for the Hardy-Weinberg genetic equilibrium to apply to
a population?
40. Describe the three different types of natural selection and explain three examples of
specific species that have undergone the different natural selections.
41. Explain three different ways speciation can occur.
42.