Trophic levels
Show on a big screenIn grass → deer → lion, which one is the second step?
- Grass, a deer, a lion — in feeding order.
- Grass is level 1: the producer.
- The deer is level 2: it eats the producer.
- The lion is level 3. A rabbit and a fox sit at level 2 and 3 too, in a different chain.
Drag the level. Watch both chains light up.
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The deer is the second step, level 2. It eats the grass.
New words
Trophic level — an organism's step number in a chain, from the producer. Level 1 is a producer.
A primary consumer eats the producer. A secondary consumer eats a primary consumer.
The rule
The producer is level 1. Whatever eats the producer is level 2. Whatever eats that is level 3, and so on. The same level number holds different animals in different chains.
| Level | Chain 1 | Chain 2 | Job |
|---|---|---|---|
| 1 | Grass | Grass | Producer |
| 2 | Deer | Rabbit | Primary consumer |
| 3 | Lion | Fox | Secondary consumer |
Most food chains have only three or four levels. Beyond that, too little energy is left to feed one more level.
Watch out!
A lion is not level 3 in every chain. A longer chain can put a lion at level 4. The level depends on the chain, not on the animal.
Try the lab to finish this lesson.