| A | B |
|---|
| Species | A population whose members have the potential to breed in nature and produce fertile offspring. |
| Allopatric Speciation | The formation of species caused by geographic isolation; ex. river or mountains. |
| Sympatric Speciation | The formation of a new species caused by something other than geographic isolation; occurs more often in plants. |
| Polyploidy | Having more than two complete sets of chromosomes; often the cause of sympatric speciation. |
| Habitat Isolation | A prezygotic barrier where two organisms of tthe same species live in the same area but rarely encounter each other. |
| Behavioral Isolation | A prezygotic barrier where one species has an elaborate courtship ritual that is not recognized by another species. |
| Temporal Isolation | A prezygotic barrier where a species has specific breeding season; ex. breeds only in the spring. |
| Mechanical Isolation | A prezygotic barrier where organisms are unable to mate because of anatomical or biochemical incompatibility; also named reproductive isolation. |
| Divergent Evolution | A pattern of evolution that occurs when a population becomes isolated from the rest of the species, becomes exposed to new selective pressures, and evolves into a new species |
| Convergent Evolution | A pattern of evolution that occurs when unrelated species occupy the same environment, are subjected to the same environmental pressures, and show similar adaptations. |
| Parallel Evolution | A pattern of evolution that describes two related species that have made similar evolutionary adaptations after their divergence from a common ancestor. |
| Coevolution | A pattern of evolution where two interacting species (flower/pollinator) have evolved at the same pace. |
| Adaptive Radiation | A pattern of evolution where one common ancestor results in the emergence of numerous new species; ex. Darwin's finches. |
| Punctuated Equilibrium | A theory of evolution that proposes new species appeared suddently; after long periods of stasis. A new species arises and replaces the ancestral species. |
| Gradualism | A theory of evolution suggesting that organisms descended from a common ancestor gradually, over a long period of time. |
| Speciation | The formation of a new species. |
