Define 'biological species.'

Add labels to the figure that follows, which illustrates the three steps required for speciation to occur.

How are hypotheses about the evolutionary relationships among living organisms tested?

Which of the following is an example of a prefertilization barrier to reproduction?

a. A female mammal is unable to carry a hybrid offspring to term

b. Hybrid plants produce only sterile pollen

c. A hybrid between two bird species cannot perform a mating display

d. A male fly of one species performs a 'wing-waving' display that does not convince a female of another species to mate with him

e. A hybrid embryo is not able to complete development

According to the most accepted scientific hypothesis about the origin of two new species from a single common ancestor, most new species arise when

a. Many mutations occur

b. Populations of the ancestral species are isolated from one another

c. There is no natural selection

d. A supernatural creator decides that two new species would be preferable to the old one

e. The ancestral species decides to evolve

For two populations of organisms to be considered separate biological species, they must be

a. Reproductively isolated from each other

b. Unable to produce living offspring

c. Physically very different from each other

d. A and C are correct

e. A, B, and C are correct

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.

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.

The similarity in skin color among different human populations appears to be primarily the result of:

a. Natural selection

b. Convergent evolution

c. Which biological race they belong to

d. A and B are correct

e. A, B, and C are correct

The tendency of individuals to choose mates who are like themselves is called

a. Natural selection

b. Sexual selection

c. Assortative mating

d. The founder effect

e. Random mating

Phylogenies are created based on the principle that all species descending from a recent common ancestor .

a. Should be identical

b. Should share characteristics that evolved in that ancestor

c. Should be found as fossils

d. Should have identical DNA sequences

e. Should be no more similar than species that are less closely related