Question

How much chemical energy (stored as biomass) is available to primary consumers from 10,000 kcal of primary productivity?

a. 1 kcal
b. 10 kcal
c. 100 kcal
d. 1000 kcal
e. 10,000 kcal

Answer 1

The answer is “d” (1,000 kcal). As the trophic level increases energy is decreases by 10 times that of the previous level. If a system has 10,000 kcal, then the primary consumer have 10 times less (10,000/10) which is 1,000 kcal. The secondary consumers have 100 kcal and the tertiary have 10 kcal. Only 10% of the energy at each trophic level goes on to the next.