| Term | Definition |
| population | a group of organismsof the same species that live a specific geological area and interbreed |
| natural selection | the process by which individuals that have favorable variations and are better adapted to their environment survive and reproduce more successfully than less adapted individuals |
| adaptations | the process of ecoming adapted to an environment |
| reproductive isolation | condition where two populations of the same species do not breed with one another because of geographical separation |
| extinct | describes a species of oganisms that has died out completely |
| analogous structure | A body part similar in function to that of another organism |
| homologous structure | a similiar structure in two organisms can be found in the common ancestore of the organisms |
| paleontologist | a scientist that studies fossils |
| gradualism | a model of evolution in which gradual change over a long period of timeleads to biological diversity |
| punctuated equilibrium | a model of evolution in which short peridos of drastic change in species, including mass extinctions and rapid speciation, are separated by long periods little or no change |
| vestigal | a stucture in an organism that is reduced in size and function and that may have been complete and functional in the organism's ancestors |
| embryology | an organism in an early stage of development of plants and animals |
| industrial melanism | darkening of an organism's coloration due to pollution |
| divergence | the accumulation of differences between groups to form a new species |
| convergence | similarities which evolve in organisms not closely related to one another because the organisms live in similar environments |
| speciation | the formation of new species as a result of evolution by natural selection |
| ecological race | a population of a species that differs genetically from other populations of the same species because they have adapted to different environments |
| isolation | a state of separation between populations |