Campbell Biology in Focus (2nd Edition)
2nd Edition
ISBN: 9780321962751
Author: Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, Jane B. Reece
Publisher: PEARSON
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Textbook Question
Chapter 21.3, Problem 3CC
WHAT IF? Suppose two plant populations exchange pollen and seeds. In one population, individuals of genotype AA are most common (9,000 AA, 900 A8. 100 88), while the opposite is true in the other population (100 AA, 900 Aa, 9,000 aa). If neither allele has a selective advantage, what will happen over time to the allele and genotype frequencies of these populations?
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Students have asked these similar questions
Exercse 2 #1 - In what populations do we see the high frequencies (above 80%) of the allele associated with lighter
pigmentation?
O Chinese
O African
O Japanese
O Bangladeshi
V French
O Mongolian
V Italian
V German
O Indian
O Turkish
Indonesian
Question 2
Exercse 2 #4 - Why might some light-skinned populations, such as the Japanese, be missing the F374 allele?
O Some populations, such as Japanese, are only light-skinned because they avoid tanning.
O This allele does not cause depigmentation.
O There have been multiple, different mutations that have produced light skin in different populations.
The sampling of Japanese in this study probably did not capture the true incidence of the F374 allele in the population.
1. You measure the effects of a single allele (A2) on fitness in two populations of the same plant species, Population X and Population Y.
Population X lives at higher altitudes. The average excess of fitness of the A2 allele (aA2) in Population X is 1.21, and the average fitness of the population (w) is 1.0.
Population Y lives at a lower altitude. The average excess of fitness of the A2 allele (aA2) in Population Y is -1.68 and the average fitness of the population (w) is 1.0
a) Which population is likely to experience faster evolution? Why?
b) What do you predict will happen to the frequency of the A2 allele (pA2) in population X?
c) What do you predict will happen to the frequency of the A2 allele (pA2) in population Y?
d) Why do you think the average excess of fitness of the A2 allele is different in these two populations?
10
Low altitude population
When the researchers
5
grew cuttings from the
same plants in a garden
at high altitude, the high
altitude plants made
5 15 25 35 45 55 65 75
10 -
more stems
(19.89 ± 2.26 versus
28.32 +2.54).
High altitude population
5 15 25 35 45 55 65 75
Number of stems
archers took seeds from the same plant (a pure lineage) and raised
environments. The graphs above show how plants responded to different altitudes. Based on these
graphs, we can conclude:
90. Res
em in different
a. The number of stems is not influenced by the environment
b. The number of stems is a heritable trait
c. The number of stems is lower in high altitudes
d. The number of stems is higher in low altitudes
c. The number of stems is influcnccd by the cnvironment
Number of
plants
Chapter 21 Solutions
Campbell Biology in Focus (2nd Edition)
Ch. 21.1 - Explain why genetic variation within a population...Ch. 21.1 - Of all the mutations that occur in a population,...Ch. 21.1 - Prob. 3CCCh. 21.2 - A population has 700 individuals, 85 of genotype...Ch. 21.2 - The frequency of allele a is 0.45 for a population...Ch. 21.2 - WHAT IF? A locus that affects susceptibility to a...Ch. 21.3 - In what sense is natural selection more...Ch. 21.3 - Distinguish genetic drift from gene flow in terms...Ch. 21.3 - WHAT IF? Suppose two plant populations exchange...Ch. 21.4 - What is the relative fitness of a sterile mule?...
Ch. 21.4 - Explain why natural selection is the only...Ch. 21.4 - Prob. 3CCCh. 21 - Natural selection changes allele frequencies...Ch. 21 - No two people are genetically identical, except...Ch. 21 - Sparrows With average-sized w1ngs survive severe...Ch. 21 - If the nucleotide variability of a locus equals...Ch. 21 - There are 25 individuals in population 1, all with...Ch. 21 - A fruit fly population has a gene with two...Ch. 21 - FOCUS ON EVOLUTION Using at least TWO examples,...Ch. 21 - Prob. 9TYUCh. 21 - SYNTHESIZE YOUR KNOWLEDGE This kettle lake formed...
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