(a) An ecological pyramid is a graphical representation of the relationship among the organisms at different trophic levels. [1]
Pyramid of energy : [1]
(i) Shows transfer of energy from one trophic level to the next.
(ii) Always upright.
Pyramid of biomass : [1]
(i) Shows transfer of amount of food from one trophic level to the next.
(ii) Mostly upright but may be inverted also.
Pyramid of numbers : [1]
(i) It shows the number of organisms at each trophic level.
(ii) Mostly upright. It may be inverted.
(b) Limitations of ecological pyramids are: [1]
(i) It does not accomodate the food web.
(ii) It does not take into account the same species and saprophytes are not given any place.