| A | B |
|---|
| ecosystem | all the living and nonliving things that interact in an area |
| ecology | the study of how living things interact with each other and their environment |
| habitat | the place where an organism lives and that provides the things the organism needs |
| biotic factor | a living part of an ecosystem |
| abiotic factor | a nonliving part of an ecosystem |
| population | all the members of one species in a particular area |
| community | all the different populations that live together in an area |
| population density | the number of individuals in a specific area |
| estimate | an approximation of a number based on reasonable assumptions |
| birth rate | the number of births in a population in a certain amount of time |
| death rate | the number of deaths in a certain amount of time |
| immigration | moving into a population |
| emigration | leaving a population |
