Food chains
A food chain is the sequence in which food and energy flow through a series of organisms, starting from a producer and passing in turn to primary consumers, secondary consumers and so on.
It can be shown as a straight-line diagram:
Figure to be added
| Link | Organism | Feeds on |
|---|---|---|
| Producer | Grass | Sunlight — makes its own food |
| Primary consumer | Grasshopper | The producer |
| Secondary consumer | Frog | The primary consumer |
| Tertiary consumer | Cobra | The secondary consumer |
| Quaternary consumer | Hawk | The tertiary consumer |
Why the arrows point the way they do
An arrow in a food chain means "is eaten by", so it points from the food to the eater, the way the energy travels. Grass → grasshopper says the energy in the grass passes into the grasshopper. Every chain begins with a producer, because only producers can capture energy from outside the living world — sunlight — and store it in food. Everything after that is passing that same energy along. A food chain is a single thread pulled out of the food web: it shows one route clearly, but in nature the frog also eats other insects, and the snake other frogs.
Arrows point to the eater
Drawing frog → grasshopper ("the frog eats the grasshopper") reverses the flow of energy. Always point from the food to the one that eats it.
Producer first, energy along the arrows
A food chain runs producer → primary → secondary → tertiary consumer, the arrows following the energy.