7.4.3 Transfer of Biomass

What do pyramids of biomass show?

They show the relative biomass at each trophic level, representing the relative weights of material.

Why is there less biomass as you move up the trophic levels?

Because only a small proportion of biomass is transferred at each level; much is lost through respiration, waste products, and uneaten material.

What percentage of biomass is typically transferred from one trophic level to the next?

Only about 10% of the biomass of each trophic level is transferred to the next.

Why can't all biomass be eaten by consumers?

Some parts, such as bone, hooves, claws, and teeth, cannot usually be digested or consumed.

Why is not all of the biomass eaten converted into new biomass in the consumer?

Some biomass is used in respiration (releasing CO₂), excreted as urea in urine, or lost as faeces because not all material can be digested.

What percentage of incident energy from sunlight do producers typically transfer into biomass?

Producers such as plants and algae transfer about 1% of incident light energy into biomass.

How is the efficiency of biomass transfer calculated?

(Biomass transferred to the next level ÷ Biomass available at the previous level) × 100

Why are fewer organisms usually found at higher trophic levels?

Because less biomass is transferred at each stage, leaving less energy available to support large populations at higher levels.