Find out about food chains and webs in this KS3 Science quiz. A food chain shows the dependency of organisms on other organisms as a source of food. It shows how energy is transferred in a habitat. A food web is just a lot of food chains linked together - it gives a more complete picture of what eats what in a natural habitat. All food chains begin with a plant, plants are called producers. They produce their own food by the process of photosynthesis and are the source of energy for the entire food chain. Animals in a food chain are consumers as they need to eat plants and other animals.
An animal that eats only plants is a herbivore and can be referred to as a primary consumer. Animals that eat other animals are either carnivores (only eat other animals, never eat plants) or omnivores (eat both animals and plants). A secondary consumer is an animal that eats herbivores and a tertiary consumer is an animal that eats secondary consumers. As you go up a food chain, there is less and less energy available which is why there are fewer tertiary consumers than secondary consumers.