Term | Definition |
Autotroph | organism that is able to capture energy from sunlight or chemicals and use it to produce its own food from inorganic compounds |
primary producer | first of energy-rich compounds that are later used by other organism |
photosynthesis | process used by plants and other autotrophs to capture light energy and use it to power chemicals reactions that convert carbon dioxide and water into oxygen and energy-rich carbohydrates such as sugars and starches |
chemosynthesis | process in which chemical energy is used to produce carbohydrates |
heterotroph | organism that obtains food by consuming other living things |
consumer | organism that relies on other organisms for its energy and food supply |
carnivor | organism that obtains energy by eating animals |
herbivor | organism that obtains energy by only eating plants |
scavenger | animal that consumes the carcasses of other animals |
omnivore | organism that obtains energy by eating both plants and animals |
decomposer | organism that breaks down and obtains energy from dead organic matter |
detritivore | organism that feeds on plant and animal remains and other dead matter |
food chain | series of steps in an ecosystem in which organisms transfer energy by eating and being eaten |
phytoplankton | photosynthetic algae found near the surface of the ocean |
food web | network of complex interaction formed by the feeding relationships among the various organisms in an ecosystem |
zooplankton | small free-floating animals that form part of plankton |
trophic level | each step in a food chain or food web |
ecological pyramid | illustration of the relative amounts of energy or matter contained within each trophic level in a given food chain or food web |
biomass | total amount of living tissue within a given trophic level |
biogeochemical cycle | process is which elements, chemical compounds,and other forms of matter are passed from one organism to another and form one part of the biosphere to another |
nutrient | chemical substance that an organism needs to sustain life |
nitrogen fixation | process of converting nitrogen gas into nitrogen compounds that plants can absorb and use |
denitrification | process by which bacteria convert nitrates into nitrogen gas |
limiting nutrient | single essential nutrient that limits productivity in an ecosystem |