Which of the following is not used to draw the ecological pyramid?

The correct answer is Option (1) → Fresh weight

Note: NCERT says that biomass is expressed in terms of fresh or dry weight, and that dry weight is the more accurate measure. So fresh weight is not wrong, as explained below.

An ecological pyramid shows the relation between the trophic levels of a food chain. The three pyramids usually studied are the pyramid of number, the pyramid of biomass and the pyramid of energy.

Option (1) Fresh weight — Not used to draw the ecological pyramid. Fresh weight includes the water held in the body, and the amount of water differs a lot between organisms. So it does not give a true measure of living matter. That is why the pyramid of biomass is drawn with dry weight.

Option (2) Dry weight — Used to draw the ecological pyramid. The pyramid of biomass shows the dry weight of the living matter at each trophic level.

Option (3) No. of individuals — Used to draw the ecological pyramid. The pyramid of number counts the individuals at each level. In a grassland, for example, the grasses are the most numerous.

Option (4) Rate of transfer of energy — Used to draw the ecological pyramid. The pyramid of energy shows the energy that flows to each level in a given area and time. Only about 10 per cent passes on to the next level, so this pyramid is always upright.

NCERT Extract:
Energy Flow – …