Primary producers. Autotroph means "self-feeder," and these organisms are distinguished by the fact that they do not depend on other organisms as a source of energy. Instead, they obtain energy from the Sun and carbondioxide from the atmosphere, and from these constituents they build the large organic molecules that they need to survive.
The buildup of toxic chemical pollutants in the fatty tissues of organisms.
The changes that particular elements undergo as they pass back and forth through the various earth systems (e.g., the biosphere) and particularly between living and non-living matter. The elements involved in biogeochemical cycles are hydrogen, oxygen, carbon, nitrogen, phosphorus, and sulfur.
The living components of an ecosystem.
The increase in bioaccumulated contamination at higher levels of the food web. Biomagnification results from the fact that larger organisms consume larger quantities of food—and, hence, in the case of polluted materials, more toxins.
The combined mass of all organisms at a particular trophic level in a food web.
A large ecosystem, characterized by its dominant life-forms.
A combination of all living things on Earth—plants, mammals, birds, amphibians, reptiles, aquatic life, insects, viruses, single-cell organisms, and so on—as well as all formerly living things that have not yet decomposed.
A combination of all flora and fauna (plant and animal life, respectively) in a region.
A meat-eating organism, or an organism that eats only meat (as distinguished from an omnivore).
That portion of the food web occupied by detritivores and decomposers. (Compare with grazing food web. )
Organisms that obtain their energy from the chemical breakdown of dead organisms as well as from animal and plant waste products. The principal forms of decomposer are bacteria and fungi.
A chemical reaction in which a compound is broken down into simpler compounds, or into its constituent elements. In the biosphere, this often is achieved through the help of detritivores and decomposers.
Organisms that feed on waste matter, breaking organic material down into inorganic substances that then can become available to the biosphere in the form of nutrients for plants. Their function is similar to that of decomposers;however, unlike decomposers—which tend to be bacteria or fungi—detritivores are relatively complex organisms, such as earthworms or maggots.
The study of the relationships between organisms and their environments.
A community of interdependent organisms along with the inorganic components of their environment.
The flow of energy between organisms in a food web.
A law of physics stating that the amount of energy in a system remains constant, and therefore it is impossible to perform work that results in an energy output greater than the energy input.
A series of singular organisms in which each plant or animal depends on the organism that precedes it. Food chains rarely exist in nature; therefore, scientists prefer the term food web.
A term describing the interaction of plants, herbivores, carnivores, omnivores, decomposers, and detritivores in an ecosystem. Each of these organisms consumes nutrients and passes them along to other organisms (or, in the case of the decomposer food web, to the soil and environment). The food web maybe thought of as a bundle or network of food chains, but since the latter rarely existseparately, scientists prefer the concept of a food web to that of a food chain.
That portion of the food web occupied by autotrophs, herbivores, carnivores, and omnivores.(Compare with decomposer food web. )
A plant-eating organism.
Secondary consumers, or "other-feeders." These creatures feed on other organisms to obtain their energy and are classified according to the types of food they eat. Thus, they are known as herbivores, carnivores, and so on.
A plant or animal that, by its presence, abundance, or chemical composition, demonstrates a particular aspect of the character or quality of the environment.
A species that plays a crucial role in the functioning of its ecosystem or that has a disproportionate influence on the structure of its ecosystem.
A term referring to the role that a particular organism plays within its biological community.
An organism that eats both plants and other animals.
At one time chemists used the term organic only in reference to living things. Now the word is applied to most compounds containing carbon, with the exception of carbonates (which are minerals) and oxides, such as carbon dioxide.
The biological conversion of light energy (that is, electromagnetic energy) from the Sun to chemical energy in plants.
Animalsthat eat green plants. (Compare with sec on dary consumers. )
Green plants that depend on photosynthesis for their nourishment.
Animals that eat other animals.
A law of physics, which can be stated in several ways, all of which mean the same thing. According to one version of the second law, it is impossible to transfer energy with perfect efficiency, because some energy always will be lost in the transfer. This is the same as saying that it is impossible to extract from a system the same amount of energy that was put into it.
Various stages within a food web. For instance, plants are on one trophic level, herbivores on another, and so on.
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