Food chains and food webs

• Producers (green plants) make their own food using energy from sunlight.
• Consumers are animals that eat other living things to get energy.
• A herbivore eats only plants, like a zebra or a grasshopper. A carnivore eats only other animals, like a lion or a snake. An omnivore eats plants and animals, like a baboon or a person.
• A food chain always starts with a producer. Each arrow points from the food to the animal that eats it: grass → grasshopper → frog → snake.

In real nature an animal eats more than one thing, and more than one animal eats it. If you draw all the chains together, you get a food web. The level an organism occupies in the web is its trophic level.

• If all the plants die, the plant eaters suffer first.
• If a predator disappears, its prey increase and the whole web is upset.
• Too much hunting or a new species brought in can upset the balance.
• Poison builds up and gets worse higher up the web.

Meerkat tip

The more kinds (biodiversity), the stronger the web.

A scavenger, like a vulture, eats animals that are already dead. Decomposers such as bacteria in the soil break down the rest and return nutrients. An ecosystem’s carrying capacity is how many animals it can support.