| A | B |
|---|
| ecosystem | living and nonliving things in an environment, together with their interactions |
| predation | an interaction in which one organism captures and feeds on another organism |
| competition | the struggle between organisms to survive in a habitat with limited resources |
| fitness | the ability of an individual to survive and reproduce in its specific environment |
| food chain | a series of steps in which organisms transfer energy by eating and being eaten |
| food web | a diagram that shows the feeding relationships between organisms in an ecosystem |
| energy pyramid | a diagram that shows the amount of energy that moves from one feeding level to another in a food web |
| trophic level | feeding level in an ecosystem |
| biomass | the total amount of living matter within a given trophic level |
| carrying capacity | the amount of a population that can be sustained based on available resources |
| natural resource | materials found in nature that are used by living things |
| primary consumer | consumer that feeds directly on producers |
| secondary consumer | consumer that eats primary consumers |
| keystone species | a species that influences the survival of many other species in an ecosystem |
| pioneer species | first species to populate an area during primary succession |
| biodiversity | the variety of different species in a given area |
| carbon cycle | the organic circulation of carbon from the atmosphere into organisms and back again |
| nitrogen cycle | the transfer of nitrogen from the atmosphere to the soil, to living organisms, and back to the atmosphere |
| biogeochemical cycle | process in which elements, chemical compounds, and other forms of matter are passed from one organism to another and from one part of the biosphere to another; like the carbon and nitrogen cycle |
| pollution | Release of harmful materials into the environment |
| disturbance | A discrete event that disrupts an ecosystem or community. Examples of natural disturbances include fires, hurricanes, tornadoes, droughts, and floods. Examples of human-caused disturbances include deforestation, overgrazing, and plowing. |
| deforestation | the removal of trees |
| eutrophication | rapid growth of algae in bodies of water, due to high levels of nitrogen and often phosphate |
