Biology (Raven), 9th Edition

Chapter 20: Genes Within Populations

Pre-Test

1
Relatively high levels of genetic variation have been found at the biochemical level (e.g. enzymes). This shows that:
A)there is variation among individuals for the different versions of enzymes.
B)there are fitness differences among individuals based on the enzyme variants.
C)selection must be occurring.
D)both a and b
E)none of the above
2
Suppose there is a population of cats with the following numbers of genotypes; BB 50; Bb 20; bb 30. If the population is in Hardy-Weinberg equilibrium, then the numbers of the genotypes would be:
A)BB 30; Bb 50; bb 20
B)BB 50; Bb 10; bb 40
C)BB 16; Bb 48; bb 36
D)BB 36; Bb 48; bb 16
E)BB 50; Bb 20; bb 30
3
Pesticide resistance has evolved in over 500 species of pest. Resistance is likely to evolve in a species because:
A)some susceptible individuals are always missed by the pesticide application.
B)a few individuals have a mutation that confers resistance to that pesticide.
C)of genetic drift.
D)the pesticide does not work very well.
E)none of the above
4
Large female fish and frogs lay more eggs than small ones. Will there be continual selection for increased size in these populations?
A)Yes, the advantage of having larger offspring will always override investment costs.
B)No, because there is a trade-off between size and survival; large individuals do not live as long as smaller ones.
C)No, because only a small proportion of eggs survive anyway because of predation and other factors.
D)No, because egg production is not a genetically determined trait.
E)None of the above.
5
Two or more alleles for a gene may be maintained in a population by the balance between:
A)mutation and selection.
B)drift and selection.
C)selection and gene flow.
D)None of the above.
E)All of the above.
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