Explain various types of ecological pyramids.

If we look at the shape of the pyramid, the base of a pyramid is broad and it narrows towards the apex.

One gets a similar shape, we express the food or energy relationship between organisms at different trophic level.

Thus relationship is expressed in terms of number, biomass or energy.

The base of each pyramid represents the producers or the first trophic level while the apex represents tertiary or top level consumer.

The three ecological pyramids that are usually studied are : $(a)$ Pyramid of number

$(b)$ Pyramid of biomass $(c)$ Pyramid of energy.

Any calculations of energy content, biomass or numbers has to include all organisms at that trophic level.

No generalization we make will be true if we take only a few individuals at any trophic level into account.

Also a given organism may occupy more than one trophic level simultaneously. One must remember that the trophic level represents a functional level, not a species as such.