Diploid cells of the fruit fly Drosophila have ten chromosomes. How many chromosomes does a
Drosophila gamete have?
1
2
5
10
20 correct answers 5
White eyes are a recessive sex-linked trait in Drosophila. If a white-eyed female fly is mated to a
red-eyed male, their offspring should be
all white-eyed females and all red-eyed males.
all white-eyed for both sexes.
all white-eyed males and all red-eyed females.
males that are 50 percent red-eyed and 50 percent white-eyed, and females that are all red-eyed.
50 percent red-eyed and 50 percent white-eyed for both sexes. correct answers all white-eyed
males and all red-eyed females.
Three different alleles (b1, b2, and b3) at the b locus exist in a hypothetical population of juniper
trees. If the frequency of b1 is 0.4, what can be said about the frequency of b3?
It cannot be greater than 0.6.
It cannot be less than 0.4.
It is 0.
It is 0.3.
,Insufficient information is given to answer the question. correct answers It cannot be greater than
0.6.
If variation at a given locus has no effect on the phenotype of individuals, which of the following
evolutionary processes will still occur at that locus?
Nonrandom mating
Natural selection
Genetic drift
Purifying selection
Positive selection correct answers Genetic drift
Which of the following statements about evolution is false?
Scientists can observe evolution in action.
Evolutionary theory can be applied to solve practical problems.
Biologists have accumulated a large body of evidence about the evolutionary changes that have
occurred in the past.
Biologists have accumulated a large body of evidence about how evolutionary changes occur.
All of the above are true; none is false correct answers All of the above are true; none is false
A population of marmots has an allele frequency of 80 percent for one allele of a locus with two
alleles. Out of 750 individuals, _______ should be heterozygotes if the population is at Hardyâ
Weinberg equilibrium.
120
240
320
480
, 640 correct answers 240
Suppose mutation and selection no longer occurred in a small, isolated population of nematodes.
Which process would most likely continue operating, and what would be the most likely effect
on the extent of genetic variation?
Gene flow would lead to an increase in genetic variation.
Gene flow would lead to a decrease in genetic variation.
Genetic drift would lead to an increase in genetic variation.
Genetic drift would lead to a decrease in genetic variation.
Genetic drift would operate but would have no effect on genetic variation. correct answers
Genetic drift would lead to a decrease in genetic variation.
If white-eyed flies are crossed with other white-eyed flies from the same strain, the offspring will
all have white eyes. This trait can thus be said to be
true breeding.
dominant.
filial.
recessive.
heterozygous. correct answers True breeding
Mendel performed a cross between two individuals, each heterozygous for three different traits
controlled by unlinked genes: Green versus yellow seeds (green is dominant), red versus white
flowers (red is dominant), and green versus yellow pods (green is dominant). What fraction of
the offspring should have green seeds, red flowers, and green pods?
3/64
3/32