Question

Construct a pyramid of biomass starting with Phytoplanktons and label three trophic levels. Is the pyramid upright or inverted ?

Hint:

In a sea ecosystem phytoplankton biomass is less than that of zooplankton and fish, so the pyramid is inverted.

Answer 1

Step 1: Choose the ecosystem:
Phytoplankton are the producers of a marine (sea) ecosystem. So the food chain is phytoplankton to zooplankton to fish.

Step 2: Build the pyramid:
From the base to the top, the labelled trophic levels would be:
Trophic level 1 (producers): phytoplankton, with a small standing biomass.
Trophic level 2 (primary consumers): zooplankton, with a larger biomass.
Trophic level 3 (secondary consumers): small fish, with the largest biomass.
A neat sketch is expected: three bars, the one for phytoplankton narrowest and placed at the bottom, and each higher bar wider than the one below.

Step 3: Shape of the pyramid:
Phytoplankton grow and divide fast but are eaten fast, so the biomass present at any time is small. Consumers live longer and add up to a bigger biomass.
So the pyramid is inverted.

Final Answer:
The pyramid of biomass in the sea (phytoplankton, zooplankton, fish) is inverted.