Observe the diagram and answer the question.
Identify the statements which are true for figure 'X' and 'Y’?
(A) Figure 'X' shows an ideal pyramid of energy
(B) Figure 'X' shows sharp decrease in biomass at higher trophic levels.
(C) Figure 'Y' shows pyramid in which a small standing crop of primary producers support a large standing crop of primary consumers.
(D) Figure 'Y' shows the flow of energy in a pyramid.
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → (A), (B) and (C) only
(A) Figure 'X' shows an ideal pyramid of energy — True. An upright pyramid; a pyramid of energy is always upright.
(B) Figure 'X' shows sharp decrease in biomass at higher trophic levels. — True. Each higher bar is smaller.
(C) Figure 'Y' shows pyramid in which a small standing crop of primary producers support a large standing crop of primary consumers. — True. The inverted pyramid of biomass in the sea.
(D) Figure 'Y' shows the flow of energy in a pyramid. — False. A pyramid of energy can never be inverted.
NCERT Extract:
Ecological Pyramids – “… In most ecosystems, all the pyramids, of number, of energy and biomass are upright, i.e., producers are more in number and biomass than the herbivores, and herbivores are more in number and biomass than the carnivores. Also energy at a lower trophic level is always more than at a higher level. There are exceptions to this generalisation: … The pyramid of biomass in sea is generally inverted because the biomass of fishes far exceeds that of phytoplankton.”