Food chain
Exam-ready definition
A diagram showing the transfer of energy from one organism to the next, beginning with a producer. For example: grass → grasshopper → frog → snake.
How this is marked
Arrows show energy flow and must point from eaten to eater. Reversed arrows lose all marks for the diagram. Only about 10% of energy passes to the next trophic level; the rest is lost via respiration, movement, heat and uneaten parts.
In an exam answer
Reading energy flow: 'In the food chain grass → grasshopper → frog, the arrows show energy being transferred from the producer to the consumers.'
Full topic guide: Organisms & their environment
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