Food chains and food webs
Biology · Key Stage 2 · The School
One chain is too simple
A food chain shows one path: grass, then rabbit, then fox. But a fox does not only eat rabbits. It might eat mice too. And a rabbit is not only eaten by foxes. Owls eat rabbits as well. One simple chain misses most of what really happens. Real habitats are almost always more complicated than that.
A web of many chains
A FOOD WEB joins many food chains together. It shows all the different things an animal might eat, and all the different animals that might eat it. A real habitat always looks more like a web than a single straight line. Even a small pond can have a surprisingly busy web. Scientists build these webs by watching what really eats what.
Reading a food web
An arrow in a food web still means the same thing as in a chain: energy flows from the thing eaten to the thing eating it. A food web just has many more arrows, because most animals eat more than one kind of food. Reading all those arrows takes a little practice at first.
Imagine a food web where foxes eat both rabbits and mice. If all the rabbits disappeared, the foxes would not starve straight away. They could eat more mice instead. But the mice population might then fall, because more of them are being eaten. And the grass the rabbits used to eat might grow thicker, since nothing is nibbling it any more. One missing animal changes several others, not just the ones directly connected to it.