Which one of the following(s) is/ are inverted pyramid in an ecosystem?
(A) Pyramid of energy
(B) Pyramid of biomass (land)
(C) Pyramid of biomass (sea)
(D) Pyramid of Number
Choose the correct answer:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → (C) only
(A) Pyramid of energy — Never inverted. Energy is lost as heat at every step, so each level always has less energy than the one below.
(B) Pyramid of biomass (land) — Upright. On land, plants have far more biomass than the herbivores, and herbivores more than the carnivores.
(C) Pyramid of biomass (sea) — Inverted. In the sea, the biomass of fishes far exceeds that of phytoplankton. Phytoplankton are few at any one time, but they multiply very fast and are eaten fast.
(D) Pyramid of Number — Upright in most ecosystems. Producers are usually the most numerous. It turns inverted only in exceptions, such as one big tree feeding many insects.
Note: One can argue that (D) is also correct, because the pyramid of numbers for insects feeding on a big tree is inverted. That is an exception, while the pyramid of biomass in the sea is “generally inverted”. No option gives (C) and (D) together, so Option (2) is the most appropriate answer.
NCERT Extract:
Ecological Pyramids – …
