Food Chains

About Food Chains

In nature, life continues because of the flow of energy from one living thing to another. This energy is passed on when something is eaten and these feeding relationships between different organisms can be shown using a picture called a FOOD CHAIN.

Food chains always start with PLANTS, as they are the organisms that PRODUCE the energy in the first place, so they are known as PRODUCERS.

Plants use a process called PHOTOSYNTHESIS in order to harness energy from the sun and turn it into food that they can use to grow and reproduce. So, in a food chain plants are always at the bottom and the chain grows upwards.

Plants are eaten by organisms which are described as PRIMARY CONSUMERS. They have this name because they are the first organisms to 'consume' something else. Primary consumers are mostly HERBIVORES, i.e. they only eat plants, although animals that eat both plants and animals, (OMNIVORES) can also be primary consumers. When a primary consumer eats a plant, only about 10% of energy of a producer is transferred to the primary consumer that eats it. The rest of the energy is lost - mostly as heat, with some of it being used up in the eating and digestion process.

Primary consumers are then eaten by SECONDARY CONSUMERS. Secondary consumers are CARNIVORES, ( meat eaters) and they are sometimes cannibals, (this means they eat other animals of the same type as themselves.) TERTIARY CONSUMERS eat the secondary and the primary consumers.

So, secondary and tertiary consumers are known as PREDATORS, (animals which hunt down and kill other animals for food), and the animals they hunt and kill are known as PREY.

As the food chain builds up it gets to a point where you come across an animal which has no natural predators. This animal is described as being at the top of the food chain.

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