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Question
What are trophic levels? Give an example of a food chain and state the different trophic levels in it.
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Solution 1
The various links or steps in a food chain at which the transfer of food and energy takes place are called trophic levels.
The producers form the first trophic level as they manufacture food. The primary consumers form the second trophic level, the secondary consumers form the third, and the tertiary consumers form the fourth trophic level.
In the above fig. The grass is the producer, which is eaten by the grasshopper, known as the primary consumer. Then the grasshopper is eaten by a shrew, a secondary consumer, and lastly shrew is eaten up by an owl, a tertiary consumer.
Solution 2
The various steps in food chain at which transfer of food energy takes place are called trophic levels.
Example: Food chain operating in a grassland.
Grass → Insects → Frogs → Snakes
- Grass → 1 st trophic level
- Insects → 2 nd trophic level
- Frogs → 3 rd trophic level
- Birds → 4 th trophic level
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