| A | B |
|---|
| Biomass | A measure of the mass of organisms within a region divided by the area of that region |
| Ecological pyramid | A diagram that shows the biomass of organisms at each trophic level |
| Ecology | The study of relationships among organisms in ecosystems |
| Ecosystem | An association of living organisms and their physical environment |
| Greenhouse effect | The process by which certain gases (principally water, carbon dioxide, and methane) trap heat that would otherwise escape the earth and radiate into space |
| Primary consumer | An organism that eats producers |
| Secondary consumer | An organism that eats primary consumers |
| Tertiary consumer | An organism that eats secondary consumers |
| Transpiration | Evaporation of water from the leaves of a plant |
| Watershed | An ecosystem where all water runoff drains into a single river or stream |
