Title: Unit 2 Glossary
Course: BIS 105 Environmental Biology > Section: BIS 105 Environmental Biology

Unit 2 Glossary

Terms

Term | Definitions
abiotic components | The non-living physical aspects of the environment; includes sunlight, soil, temperature, wind, water, and air; also known as abiotic factors.
ammonification | The release of nitrogen in the form of ammonium ions (NH<sub>4</sub><sup>−</sup>) due to the break down of organic remains and wastes by decomposers.
aquifer | An underground layer of water-bearing, permeable rock.
autotrophs | Organisms that produce organic compounds from energy and simple inorganic molecules; also known as producers.
biogeochemical cycle | A closed loop through which a chemical element or water moves through ecosystems.
biosphere | The areas of Earth where all organisms live; extends from about 11,000 meters below sea level to 15,000 meters above sea level.
biotic components | The living organisms in the environment; also known as biotic factors.
carbon cycle | Pathways of exchange that interconnect the four major reservoirs of carbon: the ocean, the atmosphere, the biosphere and organic sediments, such as fossil fuels.
cellular respiration | The process by which cells oxidize glucose and produce carbon dioxide, water, and energy.
chemoautotrophs | Organisms that use the energy stored in chemical compounds to make organic molecules by chemosynthesis.
community | Populations of different species that live in the same area and interact with one another.
consumers | Organisms that depend on producers or other types of organisms for food.
decomposers | Organisms that consume dead organisms and other organic waste.
denitrification | The conversion of some of the nitrates in soil back into nitrogen gas; done by denitrifying bacteria; returns nitrogen gas back to the atmosphere, where it can continue the nitrogen cycle.
detritivores | Organisms that consume the remains of dead plants, animals, and feces (detritus).
ecology | The scientific study of the interactions of living things with each other and their relationships with the environment.
ecosystem | A natural unit consisting of all the living organisms in an area functioning together with all the nonliving physical factors of the environment.
food chain | A simple linear pathway through which energy and materials are transferred from one species to another in an ecosystem.
food web | A diagram of feeding relationships that includes multiple intersecting food chains.
habitat | The physical environment to which an organism has become adapted and in which it can survive.
herbivores | Organisms that consume only producers such as plants or algae; form a necessary link between producers and other consumers.
heterotrophs | Organisms that depend on producers or other types of organisms for food; also called consumers.
infiltration | Rain that falls on land and soaks into the ground.
niche | The role of a species in its ecosystem; includes all the ways species’ members interact with the abiotic and biotic components of the ecosystem.
nitrification | The process of converting ammonium ions to nitrites or nitrates.
nitrogen fixation | The process of converting nitrogen gas to nitrate ions that plants can absorb; carried out mainly by nitrogen-fixing bacteria.
organism | A life form consisting of one or more cells.
photoautotrophs | Organisms that use energy from sunlight to make food by photosynthesis; includes plants, algae, and certain bacteria.
photosynthesis | The process by which carbon dioxide and water are converted to glucose and oxygen, using sunlight for energy.
phytoplankton | All the tiny photoautotrophs found on or near the surface of a body of water; usually is the primary producer in aquatic ecosystems; includes both cyanobacteria and algae.
plankton | Large communities of producers and herbivores; made up of phytoplankton and zooplankton.
population | Organisms of the same species that live in the same area and interact with one another.
producers | Organisms that produce organic compounds from energy and simple inorganic molecules.
saprotrophs | Organisms that complete the breakdown of any remaining organic matter, such as bones, feathers, and fur of dead animals, and wood and other indigestible plant material.
trophic levels | The different feeding positions in a food chain or web.
zooplankton | All the small organisms that feed on phytoplankton; includes both single-celled organisms such as protozoa and multicellular organisms such as jellyfish.