Question

if the producers in an ecosystem start off with 1000 kj of energy available to them, approximately how much energy will be available to the secondary consumers?
1,000,000 kj
10,000 kj
100 kj
10 kj

Explanation:

Step1: Recall energy - transfer rule

In an ecosystem, only about 10% of the energy is transferred from one trophic level to the next.

Step2: Determine energy transfer to primary consumers

Producers have 1000 kJ. Primary consumers get 10% of 1000 kJ, so $1000\times0.1 = 100$ kJ.

Step3: Determine energy transfer to secondary consumers

Secondary consumers get 10% of the energy of primary - consumers. So $100\times0.1=10$ kJ.

Answer:

10 kJ