| A | B |
|---|
| Abiotic Factor | Physical, or nonliving, factor that shapes an ecosystem |
| Biomass Pyramid | Represents the total mass of living organic matter at each trophic level in an ecosystem. |
| Biome | A group of ecosystems that share similar climates and typical organisms. |
| Biosphere | Part of Earth in which life exists including land, water, and air or atmosphere. |
| Biotic Factor | A living part of an ecosystem |
| Commensalism | A relationship between two organisms of different species where one benefits and the other is neither harmed nor benefited |
| Competition | A common demand by two or more organisms upon a limited supply of a resource; for example, food, water, light, space, mates, nesting sites. |
| Decomposers | Organisms, like protists, bacteria, and fungi, that recycle nutrients back to the soil. |
| Density-Dependent | A limiting factor that depends on population size. |
| Density-Independent | A factor unrelated to the population density that limits a population. |
| Ecology | The scientific study of interactions among organisms and their environment. |
| Ecosystem | A community of organisms and their abiotic environment. |
| Energy Pyramid | Shows the amount of energy that moves from one feeding level to another in a food web. |
| First Trophic Level | Producers |
| Food Chain | A hierarchical series of organisms each dependent on the next as a source of food. |
| Food Web | A community of organisms where there are several interrelated food chains. |
| Mutualism | A relationship between two species in which both species benefit |
| Niche | An organism's particular role in an ecosystem, or how it makes its living. |
| Number Pyramid | Shows the relative number of organisms at each level. |
| Parasite | An organism that feeds on a living host. |
| Predation | An interaction in which one organism kills another for food. |
| Primary Consumer | An organism that eats producers; herbivore |
| Producer | Organisms, like plants and algae, that convert sunlight into food |
| Scavengers | Organisms that eat dead and decaying organisms |
| Second Trophic Level | All Herbivores (Primary Consumers) |
| Secondary Consumer | Organisms, like large fish, that eat small fish |
| Symbiotic | Involving a close relationship of mutual dependence; also called mutualism. |
| Third Trophic Level | Secondary Consumers (Carnivores) |
