| 1. |
Which of the following statements is true about natural selection?
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a)
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It is usually the least powerful evolutionary mechanism.
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b) |
Whether individuals are selected for or against by nature ultimately depends on their genotypes.
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c) |
It can cause minor changes in gene pool frequencies from generation to generation but not extinctions.
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| 2. |
If natural selection causes both homozygotes (AA and aa) for a trait to die in early childhood, the result for the population will be:
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a)
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extinction
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b)
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elimination of the recessive allele in one generation
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c)
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only heterozygous individuals will survive to reproduce
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| 3. |
If natural selection is against individuals who are heterozygous (Aa) for a particular trait and it always causes death in early childhood, the result for the population will be:
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a)
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only homozygous individuals (AA and aa) will survive to reproduce
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b)
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elimination of the recessive allele (a) in one generation
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c)
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only heterozygous births will occur, which will ultimately result in extinction.
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| 4. |
If natural selection is against all alleles (AA, Aa, and aa) for a particular trait and it always causes death in early childhood, the result for the population will be:
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a)
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gradual but steady decrease in the recessive allele (a)
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b)
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elimination of the recessive allele (a) in one generation, but no effect on the dominant allele (A)
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c)
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extinction in one generation
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| 5. |
If nature selects only against people who are homozygous recessive (aa) for a particular trait and it always causes death in early childhood, the result for the population will be:
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a)
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a progressive decrease in the recessive allele (a)
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b)
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an elimination of the recessive allele (a) in one generation
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c)
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a gradual increase in the number of people who are heterozygous (Aa)
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| 6. |
Natural selection can cause evolution of a population's gene pool if it selects for or against:
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a)
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either homozygote (AA or aa) but not both
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b)
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the recessive homozygote and the heterozygote (aa and Aa) but not the dominant homozygote and the heterozygote (AA and Aa)
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c)
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any genotype (AA, Aa, and aa) or combination of genotypes
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d)
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B and C
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| 7. |
In Central Africa, nature has selected for people who:
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a)
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are homozygous recessive for sickle-cell trait
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b)
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are heterozygous for sickle-cell trait
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c)
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produce only normal red blood cells
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| 8. |
In order for a new recessive allele (created by a mutation) to be selected for or against by nature, it must:
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a)
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be expressed in the phenotype of an individual
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b)
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appear in the genotype of an individual
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c)
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be inherited by at least 10% of a population
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d)
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be inherited by at least 50% of a population
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