| A | B |
|---|
| Adaptation | any characteristic of an organism-body shape,process, or behavior-that helps the organism to survive in its environment and carry out lifes process |
| biodiversity | the measure of the number of different species in a specific area. |
| common ancestor | the shared ancestor fo new, different species that a rose form one population |
| fossil | the trace or remains of ancient plants and animals, which provide a history for life on Earth and help scientists form a picture of the past. |
| fossil record | all of the fossils that scientists have recoverd from the ground;provides scientists with strong evidence that life on Earth has changed over time. |
| geologic time scale | a "diary" for life on earth that is divided into time periods and that helps scientists keep track of when improtant events happen in Earth history, such as the appearance or disappearance of a species. |
| mass extinction | a large scale dying out of many species over a short periods of time |
| natural selection | process in whick organisms that are best sited to their environment survive, reproduce, and pass on their traits to their offspring; a mechanism for species change over time |
| captive breeding | the breeding of endangered species in captivity in order to build up the number of individuals in population. |
