Transcript ch 23 clicker questions

CLICKER QUESTIONS
For CAMPBELL BIOLOGY, NINTH EDITION
Jane B. Reece, Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, Robert B. Jackson
Chapter 23
The Evolution of Populations
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Questions prepared by
Jung Choi
Georgia Institute of Technology
Michael Dini
Texas Tech University
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Genetic Variation
The original source of all genetic variation is _____.
a) natural selection
b) sexual reproduction
c) independent assortment
d) recombination
e) mutation
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Evolution
In evolutionary terms, an organism's fitness is
measured by its _____.
a) stability in the face of environmental change
b) contribution to the gene pool of the next generation
c) genetic variability
d) mutation rate
e) health
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Allele Frequencies
Red short-horned cattle are homozygous for the red
allele, white cattle are homozygous for the white allele,
and roan cattle are heterozygotes. Population A
consists of 36% red, 16% white, and 48% roan cattle.
What are the allele frequencies?
a) red = 0.36, white = 0.16
b) red = 0.6, white = 0.4
c) red = 0.5, white = 0.5
d) Allele frequencies cannot be determined unless the
population is in equilibrium.
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Hardy-Weinberg Equilibrium Determination
Which of these populations are in HardyWeinberg equilibrium?
a) A
b) B
c) both A and B
d) neither A nor B
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Cystic Fibrosis 1
The frequency of cystic fibrosis, a recessive genetic
disease, is 1 per 2,500 births among Northern
Europeans. Assuming random mating, what is the
frequency of carriers?
a) 1/2,500, or about 0.04%
b) 1/50, or about 2%
c) 1/25, or about 4%
d) The frequency cannot be calculated because
selection violates Hardy-Weinberg assumptions.
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Cystic Fibrosis 2
Until the 1950s, infants born with cystic fibrosis did not
survive longer than a few months. If the frequency of
carriers was 4% in the year 1900, what proportion of
CF alleles was eliminated in one generation?
a) 100%
b) 50%
c) 4%
d) 2%
e) <0.1%
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Cystic Fibrosis 3
The frequency of cystic fibrosis is extremely low
among Asians and Africans. What may explain the
relatively high frequency of cystic fibrosis among
Northern Europeans?
a) bottleneck effect
b) founder effect
c) genetic drift
d) directional selection
e) balancing selection
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Evolution of Drug Resistance in HIV, with Time
after Initiation of Treatment
Before treatment with 3TC, did 3TC-resistant viruses
exist in these patients?
a) yes
b) no
c) no way to tell
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Mutation
If 3TC resistance carries a cost, what will happen to
the proportion of the drug-resistant virus after 3TC
treatment stops?
a) It will increase.
b) It will decline.
c) It will stay the same.
d) It will drift randomly.
e) There is no way to
predict what will
happen.
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A high proportion of the cats on Key West have
extra toes (polydactyly). What is the most likely
explanation?
a) high rate of mutation
b) founder effect
c) bottleneck effect
d) directional selection for extra toes
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