Pyramids of Biomass

• What is biomass?

  Biomass is the mass of material in a living organism.

  Almost all the biomass on the Earth is built up using energy from the sun via photosynthesis

  Biomass is often measured as the dry mass of biological material in grams

  Biomass made by plants is spread through food chains/webs
• Why are Pyramids of Biomass Pyramid Shaped?

  About 1% of incident energy from light is used in photosynthesis

  This is enough to provide biomass for almost all other organisms

  At each trophic level less of the original biomass is pass on. This is because:

  1. Not all or parts of the organism are eaten by the stage above
  2. Some biomass is lost as waste
  3. Large amounts of biomass taken in at each trophic level are used in respiration to transfer energy to the organism

  Approximately 10% of the biomass from each trophic level is transferred to the level above
• What about the decomposers?

  The detritivores and decomposers do not usually appear in pyramids of biomass or numbers

  They break down the biomass that is passed out as waste and they digest dead bodies of plants and animals