In a food chain, energy transfer is described as what happens to energy at each stage?

• A. There is less energy available to higher levels, so fewer organisms can be supported at higher levels.
• B. The energy increases at higher levels.
• C. The energy stays constant across levels.
• D. The energy is created at higher levels.

Answer: (A)

Energy moves through a food chain, but most of it is used for life processes and lost as heat at every step. When energy is transferred from one level to the next, only a portion becomes new biomass for the next organism, while the rest is used for metabolism, movement, growth, and waste heat. Because of this, the amount of energy available decreases at each higher level, so fewer organisms can be supported up the chain. A useful rule of thumb is about 10% of the energy is passed on to the next level, with the rest dissipated. So energy does not increase or stay the same, and it certainly isn’t created at higher levels; it’s steadily depleted as you move up the chain.