The biological definition of 'race' corresponds to all of the following except:a. the genealogical species concept;b. the idea that subgroups within the same species can be distinguished from each other by ancestry;c. there is a natural hierarchy of groups within a species from 'lowest' to 'highest' forms;d. it should be possible to identify races on the basis of shared allele frequencies among populations;e. races within a species are not reproductively isolated from each other.

Which of the following is an example of a postzygotic reproductive barrier?a. One Ceanothus shrub lives on acid soil, another on alkaline soil.b. Mallard and pintail ducks mate at different times of year.c. Two species of leopard frogs have different mating calls.d. Hybrid offspring of two species of jimsonweeds always die before reproducing.

Sexual selection favors individuals with traits that increase their ability to obtain mates, such as mating calls in crickets. Using this example, propose a scenario where sexual selection could contribute to divergence in sympatric speciation.

Explain how molecular chaperones facilitate protein folding in many different polypeptides, each with their own specific shape.

Cells that line your intestines are known to possess a large number of membrane proteins that transport small molecules and ions across the plasma membrane. Which of the following cell structures would you expect to be required for this characteristic of the cells?a. the endoplasmic reticulumb. peroxisomesc. lysosomesd. the cell wall

Biologists have found more than 500 species of fruit flies on the various Hawaiian Islands, all apparently descended from a single ancestor species. This example illustratesa. polyploidy.b. temporal isolation.c. adaptive radiation.d. sympatric speciation.

Why are proteins not considered to be a good candidate for the first living molecule?a. Their catalytic capability is not sufficient for most biological reactions.b. Their amino acid monomers were not likely present in the prebiotic soup.c. They cannot serve as a template for replication.d. They could not have polymerized from amino acid monomers under early Earth conditions.

All of the following statements support the hypothesis that humans cannot be classified into biological races except:a. There is more genetic diversity within a racial group than average differences between racial groups;b. Alleles that are common in one population in a racial group may be uncommon in other populations of the same race;c. Geneticists can use particular SNP alleles to identify the ancestral group(s) of any individual human;d. There are no alleles found in all members of a given racial group;e. There is genetic evidence of mixing among human populations occurring thousands of years ago until the present.

Predict the effect on protein function if each polypeptide adopted only a single, inflexible shape based on its primary structure.