| A | B |
|---|
| adaptation | characteristics that improve an individual's ability to survive and reproduce in a particular environment |
| Darwin | scientist; interested in the study of plants and animals; signed on as a naturalist on HMS Beagle; observed finches in the Galapagos Islands |
| evolution | change in inherited characteristics over generations |
| fossil | trace or remains of an organism that lived long ago, most commonly preserved in sedimentary rock |
| natural selection | a theory to explain the mechanism of evolution; process by which individuals that are better adapted to their environment survive and reproduce more successfully than less well adapted individuals |
| vestigial structure | structures that do not seem to have a function (such as appendix in humans) |
| radioactive element | an element that gives off a steady amount of radiation as it slowly changes to a nonradioactive element |
| sedimentary rocks | rock in which most fossils are found; formed when layers of sand, silt, clay, or mud are pressed and cemented together, or when minerals are deposited from a solution |
| species | a group of organisms that are closely related and can mate to produce fertile offspring |
| successive generations | generation after generation after generation of the same organism |
| variation | a difference or deviation in structure or character from others of the same species or group - may or may not improve the organism's chance for survival |
| offspring | descendants or young of people, animals, or plants collectively |
