| A | B |
|---|
| Species | A group of similar organisms that can mate with each other and produce fertile offspring |
| Adaptation | A trait that helps an organism survive and adapt |
| Evolution | Gradual changes over time of an organism |
| Scientific theory | Well tested concepts that explains a wide range of observations |
| Natural selection | Process by which individuals that are better adapted to their environment survive and reproduce more than others of their species |
| Variation | Any difference between individuals of the same species |
| Fossils | The preserved remains or traces of an organism that lives in the past |
| Sedimentary rock | Layers of sediment that build up and harden |
| Petrified fossils | Minerals replace the remains and change them into rock |
| Molds | Empty space which is the same shape as the animal |
| Casts | The same shape as the organism that made the mold |
| Relative dating | Techniques use to determine which 2 fossils are older |
| Absolute dating | Technique used to determine the actual age of a fossil |
| Radioactive elements | An unstable particle that breaks down into a different element |
| Half life | Time it takes for half of the atom in the sample to decay |
| Fossil record | Millions of fossils that scientists collected |
| Extinct | No memeber of the species that are alive |
| gradualism | Theory that evolution occurs slowly |
| Punctuated equilibrium | Theory that species evolved during a short period of time |
| Homologous structure | Similar structures related species have |
| Branching tree | diagram that shows how scientists think different groups of organisms are related |
