food web

A food web is a network showing how energy and nutrients flow through an ecosystem — essentially, a map of who eats whom. It's a more accurate picture than a simple food chain (grass → rabbit → fox) because most species eat multiple foods and are eaten by multiple predators, so the connections form a web rather than a line.

The concept was developed by British zoologist Charles Elton in his 1927 book Animal Ecology, which laid the foundation for modern ecology. Elton showed that ecosystems are organized around energy moving from primary producers (plants) up through herbivores, carnivores, and decomposers.

Food webs help explain why removing one species can cascade. When wolves were reintroduced to Yellowstone in 1995, the web shifted: elk grazed less aggressively, willows and aspens recovered along streams, beavers returned, and even river paths changed — an effect ecologists call a trophic cascade.