Which one of the following statements is correct about the pyramid of energy?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → It is always upright, and can never be inverted.
A pyramid of energy shows the energy present at each trophic level. When energy passes from one trophic level to the next, some of it is always lost as heat at each step. So each level has less energy than the one below it, and the pyramid is always broad at the base and narrow at the top.
(1) It is always inverted, and can never be upright. — Incorrect. This is the opposite of the fact. Energy is lost at every step, so the pyramid cannot be inverted.
(2) It is always upright, and can never be inverted. — Correct. The energy at a higher level is always less than at the level below it, so the pyramid of energy is upright in every ecosystem.
(3) It can neither be upright, and nor be inverted. — Incorrect. The pyramid of energy always has a shape, and that shape is upright.
(4) It is not always inverted, and can be upright. — Incorrect. This does not state the rule. It says ‘not always inverted’, which suggests that the pyramid may be inverted at times. For energy this never happens. The pyramid of energy is never inverted. The pyramid of biomass is the one that can be inverted, as in the sea, where the biomass of fishes is more than that of phytoplankton.
NCERT Extract:
Ecological Pyramids – …
