Food Chains and Food Webs — Definition

Definition

A food chain traces a sequence of feeding relationships through which organic matter and energy move, while a food web connects several such pathways. In the usual feeding diagram, an arrow points from the organism eaten to the organism that eats it.

A web reflects the fact that many organisms have more than one food source and more than one consumer. These diagrams describe relationships, rather than a permanent ranking of species. An omnivore can occupy different trophic positions depending on what it eats.

Dead material also supports feeding pathways, so a complete account extends beyond living plants and their grazers.