What is a food chain and how does energy flow through it?
Short answer
A food chain shows what eats what in a habitat. It starts with a producer, usually a green plant that makes food by photosynthesis, followed by consumers. The arrows show the direction energy flows: from the organism eaten to the organism that eats it. Only about 10% of the energy passes to each next level.
Step by step
- Producer: makes its own food using light, for example grass.
- Primary consumer: a herbivore that eats the producer.
- Secondary and tertiary consumers: carnivores that eat other consumers.
- Arrows point towards the eater.
- Energy is lost at each level through respiration, movement, heat and waste, which is why food chains are short.
Worked example
A savannah food chain
- Grass, then zebra, then lion
- Grass is the producer, the zebra is the primary consumer, the lion is the secondary consumer
- Many interlinked food chains make a food web
Common mistakes
- Drawing arrows pointing from the eater to the food.
- Saying energy is made at each level. It is transferred and some is lost.
- Forgetting that the Sun is the original source of energy.
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