| A | B |
|---|
| *ecosystem | *all the living and nonliving things that interact with each other in a particular area |
| * habitat | * the place where an organism lives and that provides the things that the organism needs |
| * population | * all the members of a species in an area |
| *community | *all the different populations that live together in an area |
| *population density | *number of individuals divided by the unit area |
| *limiting factor | * an environmental factor that prevents a population form growing |
| *carrying capacity | * the number of organisms that can be supported by an ecosystem |
| ecology | the study of how living things interact with each other and with the environment |
| direct observation | counting each organism |
| indirect observation | counting signs of organisms to estimate the population |
| sampling | counting organisms in a small area, and estimate for large area |
| mark and recapture | catch and mark organisms, catch again and compare numbers of marked organisms |
| death rate | number of deaths in a year |
| birth rate | number of births in a year |
| immigration | animals move into a population |
| emigration | animals move out of a population |
