About how many kcalories of fuel are used to produce 100 kcalories of grains?

Question

Quizplus · Accepted Answer

The average efficiency of energy transfer from one trophic level to the next is approximately 10%. This means that for every 100 kcalories consumed at one trophic level, only 10 kcalories are transferred to the next trophic level. Therefore, to produce 100 kcalories of grains, approximately 100/10 = 10 times that amount, or 1000 kcalories, of fuel (sunlight or chemical energy) would need to be used. Since the production of grains involves both photosynthesis and metabolic processes within the plant, not all of the fuel energy is necessarily "used up" in the production of 100 kcalories of grains. However, the most efficient estimate is that approximately 33 kcalories of fuel are required to produce 100 kcalories of grains (1000 kcalories of fuel/30 kcalories transferred to the next level).

About How Many Kcalories of Fuel Are Used to Produce