Term | Definition |
Ecology | The study of the interactions of living organisms with one another and with their environment |
Interdependence | The dependence of every organism on its connections with other living and nonliving parts of its environment |
Ecological Model | A model that represents or describes the relationships between the components of an ecological system |
Biosphere | The part of Earth where life exists; includes all of the living organisms on Earth |
Ecosystem | A community of organisms and their abiotic environment |
Community | A group of various species that live in the same habitat and interact with each other |
Population | A group of organisms of the same species that live in a specific geographical area and interbreed |
Habitat | The place where an organism usually lives |
Biotic Factor | An environmental factor that is associated with or results from the activities of living organisms |
Abiotic Factor | An environmental factor that is not associated with the activities of living organisms |
Tolerance Curve | A graph of the performance of an organism versus the value of an environmental variable |
Acclimation | An organism's change in response to a change in the organism's environment |
Conformer | An organism whose physiological reactions follow environmental changes |
Regulator | Organisms that use energy to control some of their internal conditions |
Dormancy | A state in which seeds, spores, bulbs, and other reproductive organs stop growth and development and reduce their metabolism, especially respiration |
Migration | In general, any movement of individuals or populations from one location to another; specifically, a periodic group movement that is characteristic of a given population or species |
Niche | The unique position occupied by a species, both in terms of its physical use of its habitat and its function within an ecological community |
Generalist | A species that has a broad niche such that the species can tolerate a wide range of conditions and can use a variety of resources |
Specialist | An individual or a species that is adapted to a particular environmental factor or ecological niche and that can tolerate only a narrow range of conditions |
Producer | An organism that can make organic molecules from inorganic molecules; a photosynthetic or chemosynthetic autotroph that serves as the basic food source in an ecosystem |
Chemosynthesis | The production of carbohydrates through the use of energy from inorganic molecules instead of light |
Gross Primary Productivity | The rate at which organic matter is assimilated by plants and other producers during a period of time over a certain area |
Biomass | Plant material, manure, or any other organic matter that is used as an energy source |
Net Primary Productivity | The rate at which biomass accumulates in an ecosystem |
Consumer | An organism that eats other organisms or organic matter instead of producing its own nutrients or obtaining nutrients from inorganic sources |
Herbivore | An organism that eats only plants |
Carnivore | An organism that eats animals |
Omnivore | An organism that eats both plants and animals |
Detritivore | A consumer that feeds on dead plants and animals |
Decomposer | An organism that feeds by breaking down organic matter from dead organisms; examples include bacteria and fungi |
Trophic Level | One of the steps in a food chain or food pyramid; examples include producers and primary, secondary, and tertiary consumers |
Food Chain | The pathway of energy transfer through various stages as a result of the feeding patterns of a series of organisms |
Food Web | A diagram that shows the feeding relationships between organisms in an ecosystem |
Biogeochemical Cycle | The circulation of substances through living organisms from or to the environment |
Groundwater | The water that is beneath the Earth's surface |
Water Cycle | The continuous movement of water between the atmosphere, the land, and the oceans |
Transpiration | The process by which plants release water vapor into the air through stomata; also the release of water vapor into the air by other organisms |
Carbon Cycle | The movement of carbon from the nonliving environment into living things and back |
Nitrogen Cycle | The process in which nitrogen circulates among the air, soil, water, plants, and animals in an ecosystem |
Nitrogen Fixation | The process by which gaseous nitrogen is converted into ammonia, a compound that organisms can use to make amino acids and other nitrogen-containing organic molecules |
Nitrogen-Fixing Bacteria | Bacteria that convert atmospheric nitrogen into ammonia |
Ammonification | Thee formation of ammonia compounds in the soil by the action of bacteria on decaying matter |
Nitrification | The process by which nitrites and nitrates are produced by bacteria in the soil |
Denitrification | The liberation of nitrogen from nitrogen-containing compounds by bacteria in the soil |
Phosphorus Cycle | The cyclic movement of phosphorus in different chemical forms from the environment to organisms and then back to the environment |