Food chains and food webs are representations of the predator-prey relationships between species within an ecosystem or habitat.
Many chain and web models can be applicable depending on habitat or environmental factors. Every known food chain has a base made of autotrophs, organisms able to manufacture their own food.
Food chains are overly simplistic as representatives of the relationships of living organisms in nature. Most consumers feed on multiple species and in turn, are fed upon by multiple other species.
A food web is a series of related food chains displaying the movement of energy and matter through an ecosystem.