(05.02 MC)

The diagram below shows a marine food chain with the amount of energy available to each trophic level in parentheses. Why does the amount of energy decrease as you move up the chain?

A pyramid showing the marine food chain indicating the amount of energy available to each trophic level. At the top of the pyramid, level 5 shows Tuna at an energy level of 0.5. Trophic level 4 has Mackerel at an energy level of 5, trophic level 3 has herring at an energy level of 50, followed by trophic level 2 with zooplankton at an energy level of 500 and phytoplankton at the bottom with an energy level of 2500.

A: Decomposers are using up the energy between each trophic level.

B: Individual organisms at the upper trophic levels require less energy to survive than those at the lower ones.

C: Producers use most of the energy before it can reach the upper levels.

D: Some energy is lost as heat or not consumed by organisms at the next trophic level.

As you can see from the diagram, the energy in a food chain is passed in a unidirectional way, starting with producers, passing through consumers and ending between decomposers.

The amount of energy becomes smaller and smaller as the trophic level rises, as a result, the higher trophic levels have less energy. This is because the transfer of energy from the lowest to the highest trophic level causes a loss of energy in the form of heat, in addition, often the energy is not consumed by the organism of the next trophic.