Which trophic level contains the most energy in a typical ecosystem?

• A. Producers
• B. Primary consumers
• C. Secondary consumers
• D. Decomposers

Answer: (A)

Energy flows from sunlight into living things through producers, which capture light and store that energy as chemical energy in biomass. They form the base of the food web, so they accumulate the most energy in the ecosystem. As energy moves up to primary consumers, then secondary consumers, only a small fraction is transferred at each step (much is lost as heat or used for the organism’s own metabolism). This makes the energy content at higher levels steadily smaller. Decomposers recycle nutrients from dead matter, but the energy they access is drawn from what producers already stored and from other organisms, so they don’t hold more energy than the producers.