In a grassland ecosystem, $20, 000 J$ of solar energy falls on green plants. Calculate the amount of energy transferred to the tertiary consumer in this food chain.

medium 3 marks Class 10 · Science · Our Environment

Answer

0.2 J

The correct answer is $0.2 J$ — Step 4: Calculate energy transferred to tertiary consumers (top carnivores): Energy = $10% of 2 J = \frac{10}{100} \times 2 = 0.2 J$ .

Step-by-step solution

Step 1: Green plants (producers) capture only about $1%$ of the total solar energy falling on their leaves. Calculate energy captured by producers: Energy captured = $1% of 20, 000 J = \frac{1}{100} \times 20, 000 = 200 J$ .
Step 2: According to the $10%$ law, only $10%$ of the energy stored at one trophic level is transferred to the next. Calculate energy available to primary consumers (herbivores): Energy = $10% of 200 J = \frac{10}{100} \times 200 = 20 J$ .
Step 3: Calculate energy transferred to secondary consumers (small carnivores): Energy = $10% of 20 J = \frac{10}{100} \times 20 = 2 J$ .
Step 4: Calculate energy transferred to tertiary consumers (top carnivores): Energy = $10% of 2 J = \frac{10}{100} \times 2 = 0.2 J$ .

Common mistake: Applying the 10% rule directly to the total incident solar energy instead of first taking 1% for producers.

Concept tested: Ten percent law of energy transfer

Published 24 August 2026 · How this solution was prepared and checked

In a grassland ecosystem, 20,000 J of solar energy falls on green plants. Calculate the amount of energy transferred to the tertiary consumer in this food chain.

Step-by-step solution

Related questions

In a grassland ecosystem, $20, 000 J$ of solar energy falls on green plants. Calculate the amount of energy transferred to the tertiary consumer in this food chain.