A. Genetic drift does not require the presence of variation.

B. Genetic drift does not involve competition between members of a species.

C. Genetic drift never occurs in nature, natural selection does.

D. There is no difference.

A. Extinctions never occur--there are unexplored parts of the globe where organisms that appear to have gone extinct may still live.

B. Extinctions occur when the slow adaptation of organisms over time to their environment is not quick enough to help them respond to changing conditions.

C. Extinctions occur at random, they do not reflect God's will.

D. Extinctions are due to catastrophic events.

A. Darwin wanted to share his theory as quickly as possible once he returned from his voyage on the Beagle.

B. It took twenty years for Darwin to develop a theory.

C. Darwin suffered from a number of illnesses.

D. Darwin was concerned about the reaction of others to the implications of his theory.

A. With natural selection "picking" is due to the fit of an organism with its environment; whereas in artificial selection, the breeder "picks" which organisms will breed.

B. Natural selection depends upon the presence of variation, artificial selection does not.

C. Natural selection occurs within populations, artificial selection does not.

D. There is a limit to how much change can be brought about by natural selection, no such limit exists for artificial selection.

A. When the organisms comprising two populations of a species can no longer interbreed, the flow of genetic material between them stops.

B. It is not important from an evolutionary standpoint. The question is based on a false assumption.

C. Reproductive isolation increases the mutation rate.

D. Reproductive isolation may slow reproduction.

A. The effect of traits on the fitness of an organism can be assessed independently of whether the organism indeed survives .

B. It is regarded as a tautology - the question is based on a false assumption.

C. There may be some statements in science that are useful even if they are not falsifiable or refutable in principle.

D. A and C.

A. Natural selection is also a random process.

B. Natural selection is nevertheless a directed process- the likelihood one variant will be favored in a given environment over another is predictable, even if the origin is not.

C. There is no possibility God could be involved in this process.

D. A, B and C.

A. Scientists recognized that once one thinks about species as populations, rather than individuals, there is no incompatibility between them.

B. Mendel's theory was replaced by the mutation theory.

C. It was recognized much of the variation we observe in nature is due to recombination, rather than mutation.

D. A and C.

A. There are patterns in the fossil record that suggest other species have diverged from a single ancestor species.

B. There are biogeographic patterns in the distribution of species, for instance distinct bird species on an island tend to resemble one another, suggesting a common ancestor.

C. There are common stages in the early embryological development of organisms representing several distinct vertebrate groups.

D. All of above

A. They are homologous because they represent modified forms of a trait present in a common ancestor (forelimbs).

B. They are analogous because while each carries out the same function (flight), this trait has arisen independently as a result of convergence (i.e. the common ancestor of both did not have a forelimb that allowed it to fly).

C. A and B.

D. They represent derived homologies.