Food chains and food webs · Year 7

Every living thing needs food. A food chain shows what eats what, and so how energy passes from one living thing to the next. It always starts with a plant, which makes its own food using light from the Sun. In real habitats, food chains join up into food webs, and a change to one animal or plant affects many others.

Key facts

  • In a food chain the arrows point from the food to the animal that eats it. They show the direction the energy goes.
  • Producers are green plants and algae: they make their own food using energy from sunlight. Every food chain starts with a producer.
  • Consumers eat other living things. Primary consumers eat producers, secondary consumers eat primary consumers, and tertiary consumers eat secondary consumers.
  • Herbivores eat only plants, carnivores eat only animals and omnivores eat both. A predator hunts and kills other animals, its prey.
  • A food web is many food chains joined together. The animal at the top, which nothing else eats, is the top (apex) predator.
  • If one population changes, others change too: if a predator dies out, its prey usually increases, and then the prey’s food decreases.
  • Decomposers, such as bacteria and fungi, break down dead plants and animals and return nutrients to the soil.

Other years