Food chains
If you were a plant you would do more than get warm when the Sun shone on you. You would make food. Sunlight sends out two forms of energy that we can detect with our bodies. They are light and heat. When sunlight strikes the surface of a leaf some of its energy is trapped. There is a substance in the plant which can hold onto energy in sunlight. This substance is green. It is called cholorophyll.

The plant uses this energy to make food from two substances in its habitat. They are water and carbon dioxide. The plant changes these substances into food. As it does so, it stores some of the energy in the food too. The plant makes food for later use but it may never get the chance to use it. The food may begin its journey along a food chain.

When a plant has made food, it may store it in its leaves, stems or roots. The food is stored so that it can be used later for growth, making flowers and seeds. When a plant makes seeds it builds up stores of food in them. Each seed contains a tiny plant and the food is stored there to help it grow into a seedling. All these food stores, leaves, stems, roots and seeds are targets for hungry animals. Some plants even entice animals to eat part of them. They make juicy fruits, which help to spread their seeds.

Animals cannot make their own food. A large number of animals get their food entirely from plants. These form the first link in the food chain. When animals eat the stored food in a plant, the energy and materials in that food pass into the animal. The materials in the food are used to build up the animal's body. Some of the energy is used to keep the animal alive and some is stored in the animal's flesh for use when food is scarce.

Some animals cannot feed on plants. They have to have their natural food. Even if they are surrounded by plants, they will not eat them but will starve to death. These animals can only feed on other animals which form the second link in the food chain. They take the materials from the body of their prey and use them to make their own body. They use some of the energy to keep themselves alive and store some for later use.

Almost all food chains begin with plants. Usually the plant is not completely eaten. Only a few leaves may be nibbled or a bite or two taken from a root. The plants in many seeds are not so lucky. The whole seed is often eaten and broken down. Only the seeds in juicy fruits are safe. They have a protective coating so that when the fruit is eaten the seed passes through the animal's body unharmed.

Animals in a food chain nearly always lose their lives when they become the food of a predator. The exceptions are the animals which are attacked by bloodsuckers, such as fleas and leeches. Blood contains food rich in energy and materials. The blood moves food round the body to the places where it is needed. Fleas and leeches bite into their prey, take in the blood they need, then let go. The animal that has been attacked survives and may even be bitten again later.

You are part of many food chains. When you eat an apple you are taking energy and materials directly from a plant and there is only one link in the chain. When you eat meat you are taking energy and food from an animal which in turn got them from grass. This means there are two links in the chain. Usually, people are always at the end of a food chain but there may have been a time when you were just another link. If you have ever had nits there was another link after you. It was made by the headlice that bit into your scalp for a drink of blood. They used the food to make eggs to lay in your hair.

Are animals that feed on plants called vegetarians?
No. This is a name given to people who do not eat meat. Animals that only feed on plants are called herbivores. This word is often used to describe animals such as cattle and sheep that feed on grass. You must remember that all animals that feed on plants are called herbivores. This includes animals like caterpillars that nibble leaves, finches that feed on seeds and greenfly that feed on plant juices.

What are animals called that feed on other animals?
They are called carnivores. This word is often used to describe lions and wolves. You must remember that all animals that feed on other animals are called carnivores. This includes animals such as frogs, which eat insects and slugs, moles, which eat earthworms, and owls, which eat mice.

Are there any animals that eat both plants and animals?
Yes, there are a few. These animals are called omnivores. Humans are omnivores because they eat food from plants and food from animals. Wild pigs are omnivores. They eat roots, acorns, eggs, beetles, mice, voles and lizards. Bears are omnivores too. They eat fish, berries, insects, fruits and young deer.

What is a prey animal?
It is an animal that is eaten by another animal. All herbivores are prey animals if they are eaten by other animals. Some carnivores can be prey animals too. A dragonfly nymph feeds on tadpoles. It is a carnivore but it is also eaten by fish. When it is eaten by a fish it is a prey animal. It is the fish's prey.

What is a predator?
It is an animal that preys on other animals. A predator is always a carnivore or an omnivore. Herbivores are never predators. People tend to think of wolves and lions as predators but predators can be small. A ladybird is a predator. It eats greenfly.

Can a food chain have more than two links?
Yes, it can. Many food chains have four or even more. An example of a food chain with four links is:

pond weed > water snail > carp > heron

Is it important which way you draw the arrows in a food chain?
Yes, it is. You must always draw an arrow going from the food to the feeder. When you eat an apple, for example, the food goes from the apple to you so the food chain is:

apple > human

Can a living thing be part of two food chains?
Yes. Most living things are part of many food chains. When the food chains in a habitat have been worked out it may be found that they can linked together. The name for a group of food chains that are linked together is called a food web.