Which diagram represents the biomass in each trophic level of an ecosystem?

• A. Energy pyramid
• B. Biomass pyramid
• C. Number pyramid
• D. Food web

Answer: (B)

The main idea here is how much living matter exists at each step of the food chain. A diagram that shows the actual mass of all organisms at each trophic level is the one that represents biomass. It’s usually drawn as a pyramid where producers form the broad base and higher trophic levels become progressively smaller, reflecting the typical decrease in biomass as you move up the chain. This pattern arises because energy transfer between levels is inefficient—only a fraction of the energy captured by producers is stored as biomass in the next level, with the rest lost as heat and used for metabolism. Therefore, biomass tends to be greatest at the base and decreases up the chain. The other diagrams illustrate different concepts: energy flow (how much energy moves through each level), the number of individuals (count of organisms at each level), or the network of feeding relationships (a food web), not the mass of living material at each level.