Question

If the grass receives 450,000 kJ of energy from the Sun, approximately how much energy is available to the blue jay?

A.
45 kJ

B.
450 kJ

C.
4,500 kJ

D.
45,000 kJ

Answer 1

C. 4,500 kJ

Using the 10% rule: only about 10% of energy transfers to the next trophic level. From grass (producer) to primary consumer = 450,000 × 0.10 = 45,000 kJ, then to the blue jay (secondary consumer) = 45,000 × 0.10 = 4,500 kJ.