Which diagram displays the number of organisms at each trophic level in a community?

• A. Energy Pyramid
• B. Pyramid of Numbers
• C. Biomass Pyramid
• D. Population Pyramid

Answer: (B)

The key idea is counting how many individual organisms occupy each trophic level in a community. The diagram that shows this is the Pyramid of Numbers. It displays the number of organisms at producers, primary consumers, secondary consumers, and so on. It often has a broad base of many producers and fewer organisms at higher levels, reflecting how energy transfer is inefficient and limits how many individuals higher up a food chain can be supported.

An energy pyramid, in contrast, shows energy flow at each level rather than how many organisms; a biomass pyramid shows the total mass of living material at each level (which can vary with organism size); and a population pyramid shows age structure of a single species, not the distribution across trophic levels in a whole community.