How does the amount of biomass at the fourth trophic level compare to the amount of biomass at the third troph?

Question

Isaac Ayoub · Accepted Answer

Biomass at the 4th trophic level would be relatively smaller than at a 3rd trophic level.

The best way to think of biomass is to break it down into simpler terms. If we take the mass of let's say a Great White shark and multiplied it by the entire amount of Great White sharks in the same trophic level, we can then calculate biomass .

4th trophic level sharks (let's assume there are 3 of them)

800 kg each, the biomass for sharks in that trophic level would just be 3 sharks x 800 kg = 2400 kg.

3rd trophic level fur seals (let's assume there are 20 of them)

200 kg each, the biomass for fur seals would be 20 fur seals x 200 kg = 4000 kg

And as we continue to go lower and lower, you'll notice a correlation between decreasing body size/mass and increasing population density.

The image below shows a biomass pyramid and a pyramid of numbers for two communities.

Peyton Budinger · Answer

undefined The amount of biomass at the fourth trophic level is typically less than the amount of biomass at the third trophic level. This is due to the energy loss that occurs as you move up the trophic levels, known as the 10% rule, where only about 10% of the energy is transferred from one trophic level to the next.