| A | B |
|---|
| Ecosystem | All the living organisms that live in an area and the nonliving features of their environment |
| Ecology | The study of the interactions that take place among organisms and their environment |
| Population | All the organisms of the same species that live in the same area at the same time |
| Community | All the populations of different species that live in an ecosystem at the same time |
| Habitat | The place within an ecosystem where an organism lives that provides the types of food, shelter, moisture level, and temperature needed for survival |
| Limiting factor | Anything that can restrict the size of a population, including living and nonliving features of an ecosystem, such as predators and drought |
| Carrying capacity | The largest number of individuals of one species that an ecosystem can support over time |
| Producer | An organism that uses an outside energy source, such as the sun, and produces its own food |
| Consumer | An organism that cannot make its own food and gets energy by eating other organisms |
| Decomposer | An organism that breaks down dead organic material returning nutrients and minerals to the environment |
| Symbiosis | A close, long-term relationship between two species that usually involves an exchange of food or energy |
| Mutualism | A symbiotic relationship in which both organisms benefit |
| Parasitism | A symbiotic relationship in which one organism benefits and the other organism is harmed |
| Commensalism | A symbiotic relationship in which one organism benefits and the other organism is not affected |
| Competition | The interaction between organisms, populations, or species, in which birth, growth, and death depend on gaining a share of a limited environmental resource |
