the process by which different kinds of living organisms are thought to have developed and diversified from earlier forms during the history of the earth

the process whereby organisms better adapted to their environment tend to survive and produce more offspring. The theory of its action was first fully expounded by Charles Darwin and is now believed to be the main process that brings about evolution

is a trait that is present in an organism, but was absent in the last common ancestor of the group being considered

the branch of biology that deals with the geographical distribution of plants and animals.

are similar physical features in organisms that share a common ancestor, but the features serve completely different functions.

is what we think was present in the common ancestor of the species of interest.

Structures that have no apparent function and appear to be residual parts from a past ancestor

are features of different species that are similar in function but not necessarily in structure and which do not derive from a common ancestral feature (compare to homologous structures) and which evolved in response to a similar environmental challenge.

an organism's ability to survive and reproduce in a particular environment.

the close external resemblance of an animal or plant (or part of one) to another animal, plant, or inanimate object

the disguising of military personnel, equipment, and installations by painting or covering them to make them blend in with their surroundings.

is a mode of natural selection in which members of one biological sex choose mates of the other sex to mate with (intersexual selection), and compete with members of the same sex for access to members of the opposite sex (intrasexual selection).

is an event that drastically reduces the size of a population

describes random fluctuations in the numbers of gene variants in a population.

occurs when a small group of migrants that is not genetically representative of the population from which they came establish in a new area.