| Term | Definition |
| ecosysystem | group of living things and the environment they live in |
| salinity | the amount of salt in water |
| population | group of the same species living in the same place at the same time |
| community | made up of all the populations that live in the same area |
| omnivore | eats all kinds of foods (meat and plants) |
| carnivore | eats meat |
| consumer | eats other living things for energy |
| producer | makes its own food |
| decomposer | feeds on the wastes and remains of plants and animals |
| ncihe | role of living things in its habitat |
| habitat | an environment that meets the needs of an organism |
| herbivore | eats plants |