Cambridge O Level Biology · Syllabus 5090 · Relationships of Organisms with One Another and with the Environment
Pyramid of Biomass
What is Pyramid of Biomass?
A diagram in which the width of each bar represents the total mass of living material at that trophic level, for a stated area and at a stated time, with the producer at the base. Biomass is preferably measured as dry mass, because the water content of organisms varies and contributes no energy or nutrients. A pyramid of biomass gives a better picture of the living material present than a count of individuals does, but it is a snapshot and the values may change with the season.
This definition is part of the Relationships of Organisms with One Another and with the Environment chapter in Cambridge O Level Biology.
Common mistakes with Pyramid of Biomass
- “Biomass means the mass of one organism.” Why it is wrong: a pyramid of biomass compares whole trophic levels, not individuals. Exam-safe: biomass is the total mass of living material at that trophic level, preferably as dry mass, for a stated area at a stated time.
Last reviewed Syllabus 2026-2028