| Term | Definition |
| Natural Selection | The process by which individuals that are better adapted to their environment are more likely to survive and reproduce than other members of the same species. |
| Overproduction creates... | competition in a population |
| Competition for... | mates, food & territory |
| Variations are caused by... | natural phenomena, reproduction defects, enviornmental changes, mutations |
| Lamarack's Theory: | aquired characteristics are passed on to children, "need" to change, use and disuse |
| Darwins's Theory | best suited will survive, overproduction creates competition, variations within a species |