Food web

A food web is a network of feeding relationships among organisms in an ecosystem, showing how energy and nutrients pass through multiple connected food chains.

Trophic level: A position in a feeding hierarchy defined by how an organism obtains energy. Trophic levels organize organisms by their positions across the web.
Producer: An organism that makes organic matter from inorganic substances, usually using light or chemical energy. Producers supply much of the energy entering food webs.
Keystone species: A species whose ecological effects are unusually large relative to its abundance. Removing a keystone species can reorganize many feeding relationships.
Energy pyramid: A diagram showing the amount of energy available at successive trophic levels. It summarizes energy quantities, while a food web maps who eats whom.
Food chain: A linear sequence of organisms through which energy passes as one organism eats another. Each chain is a single pathway within the web’s branching network.
Consumer: An organism that obtains energy by eating other organisms or organic matter. Consumers create feeding links by transferring matter between organisms.
Eutrophication: The enrichment of water with nutrients, often causing excessive algal growth and oxygen depletion. Nutrient loading can reshape aquatic food webs from producers through consumers.
Ecological network: A representation of ecological entities as nodes connected by interactions. Food webs are ecological networks specialized to feeding relationships.
Trophic cascade: A series of ecological effects caused by changes in predators or consumers across trophic levels. A shift in one feeding link can alter several connected populations.
Predation: An interaction in which one organism captures and eats another. Predation forms many of the direct links represented in food webs.

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