#139 Food chain

Credit: BBC Bitesize

Food  chain is a chart showing the flow of energy (food) from one organism to the next beginning with a producer.








Examples: 

• mahogany tree  à caterpillar à song  bird à hawk
• maize                  à locust        à lizard         à snake

• A food chain usually starts with a photosynthetic plant, which gains its energy from the Sun.
• The arrows used to link each organism to the next represent the direction of energy flow. They always points towards the ‘eater’, and away from the plant. 
• The feeding level is known as the trophic level.
• Plant are producers (they make/produce food for other organisms).
• Animals that eat plants are primary consumers (a consumer is an ‘eater’). They are also called herbivores.

Examiner’s tips

• Make sure you can write a food chain involving 3 consumers, with the arrows in the correct direction.
• Don’t include the Sun (it is not an organism). 
• Always start with the producer on the left of diagram.
• Practice labeling each trophic level in your food chain under the organisms (producer, primary consumer, etc.).
• Don’t waste time drawing plants and animals: this will not get you any extra marks. 

Common misconceptions

Marks are often lost when students write out food chains and webs because they draw the arrows the wrong way round or put the chain back-to-front (or both). The following  example was seen in a recent paper:

jackal à sheep à grass

This student is suggesting that grass eats sheep and sheep eat jackals!