Exam 21: Evolution: How Genotypes and Phenotypes Change Over Time

If there are 100 individuals in a population and 20 are homozygous for B, 60 are heterozygous, and 20 are homozygous for b, what is the allele frequency of B?

Imagine the following genotype frequencies in a population: p² = 0.49, 2pq = 0.42, q² = 0.09. Now assume that there is nonrandom mating where individuals with one genotype will only mate with individuals that also have their genotype. Assume this pattern of mating goes on until the frequency of heterozygotes is effectively zero. In addition, there is also inbreeding depression such that individuals with the genotype represented by p² die before they can reproduce. What will be the frequency of allele q?

The intricate plumage of male birds of paradise has become increasingly elaborate throughout their evolution due to females mating preferentially with males that display the most impressive feathers. This is an example of _____ selection.

You have spent time working with a population of beetles. Males range in size from 2-6 cm in length. You realize that the females only mate with males that measure less than 3 cm long. If you measured allele frequencies at a single locus that contributes to overall length, would you expect this population to be in Hardy-Weinberg equilibrium from one generation to the next?

With few exceptions, we cannot use observable traits to measure the amount of genetic variation in populations because:

Some proteins have a slower molecular clock due to _____ selection, which eliminates harmful alleles.

A researcher is studying the color of grasshopper exoskeletons. Assume that this phenotype is caused by the action of two alleles. Green grasshoppers have the genotype AA and brown grasshoppers have the genotype aa. If the frequency of the A allele in this population is 0.2, what is the frequency of the a allele?

What kind of mutation has no effect on an organism's ability to survive or reproduce?

Which of the following statements is TRUE regarding the molecular clock of hemoglobins?

Imagine the following genotype frequencies in a population: p² = 0.49, 2pq = 0.42, q² = 0.09. Now assume that there is nonrandom mating where individuals with one genotype will only mate with individuals that also have their genotype. Assume this pattern of mating goes on until the frequency of heterozygotes is effectively zero. Is this population in Hardy-Weinberg equilibrium?

Two male lions are fighting for mating rights in a pride, and one of the lions dies in the process. This is an example of _____ selection.

Given the molecular clocks in Figure 21.15 below, you can conclude that reptiles and mammals should have approximately _____ amino acid differences between them in cytochrome c.

If a gene has two alleles, and allele A has a frequency of 83%, then allele a has a frequency of:

A hypothetical endangered species of wildflower has been reduced to a single small population in a mountain meadow. A rare early spring blizzard kills all but three of the remaining plants, one of which has a rare mutation. This is an example of:

Genetic variation has two sources-mutation and:

Which of the following is a source of genetic variation?

Interbreeding groups of organisms of the same species living in the same geographical area are called:

Two populations that have been separated from each other for a long period of time will have:

When we say "populations evolve, not individuals," what does this mean?

Individuals that are heterozygous for sickle-cell anemia are more resistant to malaria than those that do not have a sickle-cell allele. Why does the sickle-cell allele not become fixed in the population?