Question

Why do different trophic levels have different amounts of energy?

Answer 1

Amount of energy available at each trophic level depends upon the number of organisms available at each level. In an ecosystem, number of organisms decrease when we move from the bottom to top and hence energy decreases. This is the reason for different trophic levels having different amounts of energy

Answer 2

Organisms at different tropic levels get their energy from the organisms at the lower tropic levels.

Explanation:

Organisms at different tropic levels are at different levels of the food chain. The Organisms must get enough energy to sustain life and reproduce. 90% of the energy an organism gets from the lower level is used up in life processes. Only 10% is available for the next highest tropic level.

For example it takes 1000 kg of food energy in grass to support 100 kg of energy in rabbits. The 100 kg of food energy in rabbits can only support 10 kg of food energy in the foxes that eat them.

Each tropic level has only 10% of the energy in the level below it that supports that tropic level in the food chain.