| A | B |
|---|
| variations | Differences between members of the same species |
| fossils | The preserved remains or traces of organisms that lived in the past |
| absolute dating | How scientists determine the actual age of fossils |
| extinct | Refers to a species that no longer has any living members |
| homologous structures | Similar structures that related species have inherited from a common ancestor |
| branching tree | A diagram showing how scientists think diferent groups of organisms are related |
| evolution | The gradual change in a species over time |
| adaption | A trait that helps an organism survive and reproduce |
| natural selection | The process by which individuals that are better adapted to their environment are more likely to survive |
| overproduction | Refers to a species creating more offspring than can possibly survive. |
| species | A group of similar organisms that can mate with each other and produce fertile offspring |
| scientific theory | A well-tested concept that explains a wide range of observations. |
| relative dating | Technique used to determine which of two fossils is older. |
| What did Darwin observe about finches? | Beaks were adapted to foods they ate. |
| How do most fossils form? | organisms are buried in sediment |
