Exam 20: Mechanisms of Evolution

Suppose a population of flour beetles has 1,000 individuals.Normally the beetles are red; however, this population is polymorphic for a mutant autosomal body color, black, designated by bb.Red is dominant to black, so BB and Bb genotypes result in red beetles.Assume the population is at Hardy-Weinberg equilibrium, with equal frequencies of the two alleles.What would be the expected frequencies of the red and black phenotypes?

Suppose the mutation rate per nucleotide in a type of fly is about 10 in a billion, that there are 300 million nucleotides in the haploid genome, and that the population size is 40 million.In this case, in every generation about _______ new mutations will appear in each individual on average.

If there are only two alleles at a given locus and the frequency of one allele is 0.6, what is the frequency of the other allele?

A neutral allele

What is the primary distinction between artificial selection and natural selection?

Under Hardy-Weinberg equilibrium, if the frequency of one allele is 0.8, then _______ percent of the population should be heterozygotes.

Which statement about Hardy-Weinberg equilibrium is true?

If a population with two alleles is at Hardy-Weinberg equilibrium and the frequency of one allele is 0.7, what is the heterozygote frequency?

In a population of mice, the average survival rates of individuals of varying sizes were assayed and are shown in the table. Assume that body size is at least partially heritable.Assuming that all other aspects are independent of size, this population is most likely experiencing ______ selection, and the variation in the population should _______over many generations.

Which of the following is not an example of adaptation?

Suppose there are two alleles at a locus and that the locus is at Hardy-Weinberg equilibrium.If the frequency of one allele is r, what is the frequency of the heterozygotes?

An allele in a population of oysters has a frequency of 0.21.Out of 600 oysters, _______ copies of the allele are present.

Shown is a table of the results of a study of grasshoppers showing frequencies of different size classes, along with the average number of offspring these individuals produce. Assuming that size is a heritable trait (and that the number of offspring is a good proxy for the fitness of the phenotype), which type of selection is operating in this population?

Two populations of raccoons are similar in most respects, but the population on the east side of a river is much smaller than that on the west side.There is little gene flow between the populations.Which statement about these populations is most accurate?

Which two evolutionary processes would most likely act in opposite ways regarding their effects on the extent of genetic variation in a population?

Suppose that in a population of 1,400 individuals, 125 individuals are homozygous for allele A7 and 450 are heterozygous for the same allele.The frequency of the A7 allele is therefore _______.

In which way are mutation and gene flow most similar?

Which would not be considered a trade-off?

Which is usually the easiest to examine without specialized equipment?

What is the main difference between Darwin and Wallace with respect to their contributions to evolutionary biology?