Practice Quiz for Natural Selection

No. of Questions= 8

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


 

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