Term | Definition |
evolution | change in a species over time; process of biological change by which descendants come to differ from their ancestors |
species | group of organisms so similar to one another that they can breed and produce fertile offspring |
fossil | trace of an organism from the past |
catastrophism | theory that states that natural disasters such as floods and volcanic eruptions shaped Earth's landforms and caused extinction of some species |
gradualism | principle that states that the changes in landforms result from slow changes over a long period of time |
uniformitarianism | theory that states that the geologic processes that shape Earth are uniform through time |
variation | differences in physical traits of an individual from the group in which it belongs |
adaptation | inherited trait that is selected over time because it allows organisms to better survive in their environment |
artificial selection | process by which humans modify a species by breeding it for certain traits |
heritability | ability of a trait to be passed from one generation to the next |
natural selection | mechanism by which individuals that have inherited beneficial adaptations produce more offspring on average than do other individuals |
population | all of the individuals of a species that live in the same area |
fitness | measure of an organism's ability to survive and produce offspring relative to other members of a population |
biogeography | study of the distribution of organisms around the world |
homologous structure | body part that is similar in structure on different organisms but performs different functions |
vestigial structure | remnants of an organ or structure that functioned in an earlier ancestor |
paleontology | study of fossils or extinct organisms |