In an energy pyramid, which level contains the most energy?

• A. Producers (the base)
• B. Tertiary consumers
• C. Primary consumers
• D. Secondary consumers

Answer: (A)

Energy moves through an ecosystem from sunlight into chemical energy stored by producers, then up to herbivores and predators. Producers, like plants and algae, capture solar energy and store it as chemical energy, so they hold the largest amount of usable energy in the system. As energy passes to primary consumers, then to secondary, and then to tertiary consumers, only a fraction—about a tenth in many cases—is transferred to the next level. The rest is used for life processes or lost as heat, so the amount of energy available decreases at each higher level. That’s why the base, with the producers, has the most energy in the pyramid.