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Chapter 16 General

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

 1. 

Which of the following describes a population?
a.
dogwood trees in Middletown, Connecticut
b.
four species of fish living in a pond
c.
dogs and cats living in Austin, Texas
 

 2. 

Variation in genotype is caused by
a.
mutations only.
b.
recombination of genes as a result of sexual reproduction.
c.
phenotypes changing more quickly than genotypes.
d.
None of the above
 

 3. 

The number of individuals with a particular phenotype divided by the total number of individuals in the population is the
a.
allele frequency.
b.
genotype frequency.
c.
phenotype frequency.
 

 4. 

RR : homozygous dominant ::
a.
Rr : heterozygous
b.
Yy : homozygous
c.
yy : heterozygous dominant
 

 5. 

recessive allele frequency : dominant allele frequency :: 0.02 :
a.
1.0
c.
0.98
b.
0.04
 

 6. 

Which of the following conditions is required for Hardy-Weinberg genetic equilibrium?
a.
No mutations occur.
b.
The population is infinitely large.
c.
Individuals neither leave nor enter the population.
d.
All of the above are required.
 

 7. 

Natural selection acts
a.
on phenotypes that are expressed.
b.
on all mutations.
c.
only on recessive alleles.
 

 8. 

The movement of alleles into or out of a population due to migration is called
a.
gene flow.
c.
mutation.
b.
nonrandom mating.
 

 9. 

Which of the following conditions can cause evolution to take place?
a.
genetic drift
c.
nonrandom mating
b.
migration
d.
All of the above
 

 10. 

Gene flow describes the
a.
movement of genes from one generation to the next.
b.
exchange of genes during recombination.
c.
movement of genes from one population to another.
 

 11. 

What type of population is most susceptible to loss of genetic variability as a result of genetic drift?
a.
large populations
b.
medium-sized populations
c.
small populations
 

 12. 

A change in the frequency of a particular gene in one direction in a population is called
a.
acquired variation.
b.
directional selection.
c.
stabilizing selection.
 

 13. 

The type of selection that may eliminate intermediate (average) phenotypes is
a.
disruptive selection.
b.
direction selection.
c.
polygenic selection.
 

 14. 

Directional selection tends to eliminate
a.
both extremes in a range of phenotypes.
b.
one extreme in a range of phenotypes.
c.
intermediate phenotypes.
d.
None of the above; it causes new phenotypes to form.
 

 15. 

The large, brightly colored tail feathers of the male peacock are valuable to him because
a.
they attract potential predators.
b.
they attract people who provide them with food.
c.
they attract potential mates.
 

 16. 

A major limitation of the morphological concept of species is that
a.
there may be a great deal of phenotypic variability in a species.
b.
organisms that actually can interbreed may have very different physical characteristics.
c.
it does not consider whether individuals of a species can mate and produce viable offspring.
d.
All of the above
 

 17. 

Speciation can occur as a result of geographic isolation because
a.
members of a species can no longer find mates.
b.
populations that live in different environments may be exposed to different selection pressures.
c.
the biological concept of species defines individuals that do not interbreed as members of different species.
d.
All of the above
 

 18. 

Which of the following is an example of postzygotic isolation?
a.
A mating call is not recognized by a potential mate.
b.
Mating times of potential mates differ.
c.
Offspring of two individuals of interbreeding species die early.
d.
None of the above
 

 19. 

The hypothesis that evolution occurs at a slow, constant rate is known as
a.
natural selection.
c.
adaptation.
b.
gradualism.
 

 20. 

The hypothesis that evolution occurs at an irregular rate through geologic time is known as
a.
punctuated equilibrium.
b.
directional evolution.
c.
directional equilibrium.
 

 21. 

Which of the following is not a form of prezygotic isolation?
a.
the formation of a sterile hybrid between two species
b.
different months of flowering of two wildflower species
c.
species-specific recognition proteins on the surfaces of egg and sperm cells
 

 22. 

Which of the following traits would not be useful to the study of the genetic variation in a population of fish?
a.
the diet of the fish
b.
the fin size of the fish
c.
the length of the fish
 

 23. 

What type of speciation occurs when new species arise as a result of geographic isolation?
a.
allopatric speciation
b.
sympatric speciation
c.
prezygotic speciation
 

 24. 

Reproductive isolation differs from geographic isolation in that
a.
members of the same species are not physically separated in reproductive isolation, whereas they are separated in geographic isolation.
b.
members of two species in which reproductive isolation occurs never try to interbreed, whereas geographically isolated ones do.
c.
geographic isolation never leads to speciation, whereas reproductive isolation sometimes does.
 

Completion
Complete each statement.
 

 25. 

_________________________ is the study of evolution from a genetic point of view.
 

 

 26. 

A ____________________ shows that most members of a population have similar values for a given measurable trait.
 

 

 27. 

____________________ results from flawed copies of individual genes.
 

 

 28. 

Alternative versions of genes are called ____________________.
 

 

 29. 

Allele ____________________ is determined by dividing the number of instances of a certain allele by the total number of alleles of all types in the population.
 

 

 30. 

According to the ______________________________ principle, allele frequencies in a population tend to remain the same from generation to generation unless acted on by outside influences.
 

 

 31. 

The movement of individuals from one population to another is called ____________________.
 

 

 32. 

When there are only a few surviving individuals of a species, the species is vulnerable to extinction because there is little if any ____________________ on which natural selection can act.
 

 

 33. 

____________________ selection causes the range of phenotypes to become narrower, increasing the number of individuals with characteristics near the middle of the range.
 

 

 34. 

Differences in physical characteristics between males and females of the same species may indicate that ____________________ selection is important in the species.
 

 

 35. 

The key element in the biological concept of species is that individuals within a species can ____________________.
 

 

 36. 

When geographic isolation occurs, ____________________ flow between separated populations ceases, which can then lead to speciation.
 

 

 37. 

Reproductive isolation that occurs before fertilization is called ____________________ isolation.
 

 

 38. 

Reproductive isolation that occurs after fertilization is called ____________________ isolation.
 

 

 39. 

____________________ is the hypothesis that evolution occurs at a constant rate.
 

 

Problem
 

 40. 

For each of the characteristics named below, describe how the characteristic might provide a selective advantage for male members of the species who possess it. Write your answers in the space below.
a.      larger than average antlers on a deer
b.      a bowerbird’s ability to build a nest more elaborate than the average nest
c.      the ability of an insect to remove another insect’s sperm packet from a female insect’s reproductive tract
 

Essay
 

 41. 

In comparing two species that look very different, how could a comparison of the species’ genes contribute to an understanding of their evolutionary relationship? Write your answer in the space below.
 

 42. 

In a population of birds, 16 of 100 individuals suffer from a recessive genetic disorder that causes the feathers to fall off their wings. What proportion of the bird population are heterozygous carriers of the disorder? Write your answer in the space below.
 

 43. 

Describe how you would determine the phenotype frequency of a certain phenotype in a population. Write your answer in the space below.
 

 44. 

An agricultural plot of land is sprayed with a very powerful insecticide to destroy harmful insects. Nevertheless, many of the same species of insects are present on the land the following year. How might evolution theory account for this phenomenon? Write your answer in the space below.
 



 
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