Exam 2 Review

What does the figure show about the fitness effects of mutations in the HSP90 protein gene of the yeast Saccharomyces cerevisiae?

• Mutations have more deleterious effects at the higher temperature.

• The effects of mutations are the same across different temperatures.

• Most mutations are lethal across different temperatures.

• Mutations have more beneficial effects at the higher temperature.

Which of the following statements is true?

• Most mutations are either neutral or deleterious with respect to fitness.

• Most mutations are beneficial with respect to fitness.

• For fitness to be affected, a mutation must affect a large portion of a gene.

• Only a small fraction of mutations are lethal.

Which of the diagrams shown illustrates an inversion?

• A

• B

• C

• D

Balancing a pencil on the tip of your finger so it doesn’t fall is an example of a(n) ___________ equilibrium.

• mixed

• neutral

• stable

• unstable

Which of these is a question that follows from population-level thinking?

• How can a man with Type A blood have a daughter with Type O blood?

• If a woman is a carrier of hemophilia, what proportion of her sons are expected to also have hemophilia?

• Why is sickle-cell anemia fairly common in the United States even if it shortens lifespan?

• How can two people without Tay-Sachs disease have a child with that disorder if there is no history of the disorder in either of their families?

In the early twentieth century, one of the criticisms of Mendel’s conclusions about inheritance was that

• Mendel’s conclusions only apply to plant species.

• Mendel provided no statistical analysis to support his conclusions.

• Mendel’s conclusions only apply to species without separate sexes.

• the traits he studied showed discrete variation, while many traits in nature show continuous variation.

Refer to the figure of the genetic code shown to answer the following question.

Which of the following mutations to a codon is most likely to be selectively neutral?

• • UUG → CUG

• • AUA → AUG

• • AAC → AAA

• • UGC → UGA

Consider a population of lizards living on the coast of Africa. A storm creates piles of debris that the lizards use to raft to a faraway uninhabited island. Which evolutionary process is happening?

• mutation selection balance

• the founder effect

• frequency-dependent selection

• coalescence

The figure shows the level of diversity at three loci in two species of elephant seals. Which of the following could be true of these species according to the data?

• The northern elephant seals have a higher mutation rate than the southern elephant seals.

• 
  The northern elephant seals have a larger effective population size than the southern elephant seals.

• The northern elephant seals experience balancing selection at these loci, and the southern elephant seals experience directional selection.

• The northern elephant seals experienced a population bottleneck, but the southern elephant seals did not.

Which of the following processes causes a neutral allele to increase in frequency because it is linked to an allele under selection?

• mutation

• genetic drift

• genetic hitchhiking

• background selection