Food Web

When many individual food chains within the same ecosystem interlock with one another, the resulting web-like arrangement of feeding relationships is called a food web — the basic functional unit that keeps an ecosystem stable in nature, a property called homeostasis. A grassland food web illustrates why real feeding relationships are rarely a single straight chain: if a rabbit is unavailable, a mouse may switch to eating food grains instead; that same mouse might then be eaten either directly by a hawk or by a snake, and the snake itself might in turn be eaten directly by the hawk — so several alternative paths exist for the same unit of energy to move through the community. Because of this interlocking structure, the species that make up an ecosystem stay balanced against one another through a kind of natural checks-and-balances system rather than depending on any single unbroken chain. Ecologically, food webs are put to several practical uses: they describe direct species interactions, reveal indirect interactions between species that never interact fa …