Class 10 Food Chains: Energy Flow and the 10 Percent Law

Read a simple chain

1. 1

   Grass: producer

   Builds organic food using captured light energy.

2. 2

   Grasshopper: primary consumer

   Obtains food by eating the producer.

3. 3

   Frog: secondary consumer

   Obtains food by eating the primary consumer.

4. 4

   Snake: tertiary consumer

   Occupies the next feeding level in this simplified chain.

Read the labelled model

Apply the energy model as an approximation

Suppose producers have 20,000 J available at their trophic level. Using the approximate ten-percent transfer model gives 2,000 J at the primary-consumer level, 200 J at the secondary level and 20 J at the tertiary level. Label the starting level before counting transfers.

This is a simplified estimate, not a claim that every ecosystem transfers exactly ten percent. Energy flows through an ecosystem and is dissipated as heat; materials can be recycled through biological and physical processes.

Distinguish three different ideas

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Use the concept in a waste explanation

Food waste can be biodegradable and still create problems if poorly managed. A useful answer connects the material, the conditions for breakdown and its effects. “Biodegradable, therefore safe to dump anywhere” is not a scientific conclusion.

For revision, draw one chain and a separate arrow system for decomposers. Then explain where energy enters and where material returns. Avoid drawing energy in a closed recycling loop or placing every decomposer exclusively after the top predator.

Choose what to study next

Sources and scope

This is a focused learning resource, not a complete chapter or a prediction of board questions. Use your current syllabus and the paper-specific marking scheme for assessment requirements.