When studying the interactions between the organisms of a community, we can distinguish food chains, where the chemical energy produced in photosynthesis moves from one organism to another. Food chains are comprised of organisms that act the parts of producers, consumers, and decomposers. When combined, food chains make up food webs.

Food webs are arrived at by conceptualizing all the food chains of a community, and the individuals within these food chains. When these relationships have been discovered, one notices that all the species of an ecosystem have relationships with all the other species within that same ecosystem. 

Food webs consist of the food chains of an ecosystem.