| A | B |
|---|
| evolution | a change in the kind of organism over time; process by with modern organisms have descended from ancient organisms |
| theory | a well-tested explanation that unifies a broad range of observations |
| variation | the differences among individuals of a species |
| artificial selection | the selection by humans for breeding of useful traits from the natural variation among different organisms |
| fitness | the ability of an organism to survive and reproduce in its environment |
| adaptation | the inherited characteristic that increases an organism's chance of survival |
| survival of the fittest | the process by which individuals that are better suited to their environment survive and reproduce most successfully; also called natural selection |
| natural selection | the process by which individuals that are better suited to their environment survive and reproduce mose successfully; also called survival of the fittest |
| descent with modification | the principle that each living species has descended, with changes, from other species over time |
| homologous structure | structures that have different mature forms in different organisms but develop from the same embryonic tissues |
| vestigial organ | a organ that serves no useful function in an organism |
| endosymbiotic theory | idea that eukaryotic cells formed from a symbiosis among several different prokaryotic organisms |
| mass extinction | event in which many types of living things die out at the same time |
| extinct | species that is no longer existant |
| adaptive radiation | process by which a single species or small group of species evolves into several different forms that live in different ways; rapid growth in the diversity of a group of organisms |
| convergent evolution | process by which unrelated organisms independently evolve similarities when adapting to similar environments |
| coevolution | process by which two species evolve in response to changes in each other |
| punctuated equilibrium | pattern of evolution in which long stable periods are interrupted by brief periods of more rapid change |
| gradualism | a slow, steady process of evolution |
| overproduction | producing more offspring than necessary to increase the chances of survival |
| phylogenetic tree | diagram that is used to show evolutionary relationships among species |
| analogous structures | structures that develop to serve the same function but develop from anatomically different structures |
