| A | B |
|---|
| biosphere | part of Earth in which life exists, including land, water, and air or atmosphere |
| ecology | scientific study of interactions among organisms and between organisms and their environment |
| species | group of similar organisms that can breed and produce fertile offspring |
| population | group of individuals of the same species that live in the same area |
| community | assemblage of different populations that live together in a defined area |
| ecosystem | all the organisms that live in a place, together with their nonliving environment |
| biotic factor | any living part of the environment with which an organism might interact |
| abiotic factor | physical, or nonliving, factor that shapes an ecosystem |
| atmosphere | thin layer of gases that surround Earth |
| hydrosphere | all of the water - saltwater and freshwater, in the form of liquid, ice, or vapor - above and below Earth's surface and in the atmosphere |
| geosphere | all of the rock at and below Earth's surface |
