The ten (10) percent rule involves how only as low as 10% of the available energy is transferred to each organism in trophic levels. In an ecosystem, the order of trophic levels are: producer ➡ primary consumer ➡ secondary consumer ➡ tertiary consumer.
According to this question, 1500 kcal of energy is starting at the producer level. Hence;
- 10% of 1500 kcal = 10/100 × 1500 = 150 kcal will be available to the primary consumer
- 10% of 150 kcal = 10/100 × 150 = 15 kcal will be available to the secondary consumer.
- 10% of 15 kcal = 10/100 × 15 = 1.5kcal will be available to the tertiary consumer.