Approximately how much energy is passed from one trophic level to the next?

• A. 10%
• B. 100%
• C. 50%
• D. 1%

Answer: (A)

The main idea here is how energy moves through an ecosystem from one trophic level to the next. When energy moves up the chain, only a small portion is passed on. Plants capture energy from the sun, but much of that energy is used for the plant’s own life processes or lost as heat. When a herbivore eats plants, about ten percent of the plant’s stored energy typically becomes new energy stored in the herbivore’s body. The same roughly ten-percent rule applies as energy moves to the next level as well. This creates the familiar energy pyramid, with much more energy at the bottom than at higher levels.

So, about ten percent is passed to the next trophic level because most energy is used for metabolism or lost as heat, leaving only a small fraction to be stored and transferred. The other options—tenfold, half, or just one percent—don’t align with how energy is lost and how biomass accumulates across trophic levels.