| A | B |
| Ecology | the study of the interactions in an ecosystem |
| Ecosystem | System made up of organisms interacting with each other and with the nonliving parts of that system |
| Biosphere | Part of the Earth where organisms can live |
| Biotic Factors | Living parts of an ecosystem |
| Abiotic Factors | Nonliving things in an ecosytem |
| Population | Group of the same type of organism living in the same place at the same time |
| Community | All of the populations living in an area |
| Limiting Factor | Something that limits the size of a population |
| Niche | Role of an organism in its ecosystem |
| Habitat | Place where an organism lives out its life |
| Threatened Species | Species needing protection but not in danger of extinction yet |
| Endangered Species | Any species in danger of becoming extinct because so few are left |
| Producer | Organism that makes its own food |
| Consumer | Organism that eats other organisms |
| Decomposer | Eats dead organisms or wastes of organisms |
| Scavenger | Animal that feeds on dead or decaying animals that it did not kill |
| Carnivore | Animal that eats the flesh of other animals |
| Herbivore | Animal that feeds on plants |
| Omnivore | Animal that eats both plants and animals |
| Predator | Catches and eats other living animals |