Pyramid of Numbers - Ecological Pyramids

A graphic representation of the total number of individuals of different species belonging to each trophic level in an ecosystem is known as pyramid of numbers. It consists of a number of horizontal bars depicting specific trophic levels which are arranged sequentially from primary producer level through herbivore, carnivore onwards. The length of each bar represents the total number of individuals

Figure: An upright pyramid of numbers. The number of individuals indicated in the figure is hypothetical, and the organisms are not drawn to the same scale.

at each trophic level in an ecosystem. The number of individuals drastically decreases with each step towards higher trophic levels and the diagrammatic representation assumes a pyramidal shape and is called pyramid of numbers. In such pyramids, you would find that generally the higher trophic levels are occupied by relatively large-sized animals which are also less abundant. This is due to the fact that animals at higher trophic levels are larger than the animals which they capture from the lower trophic level. In case of tiger or lion, the size relationship does not hold good as cattle and other preys may be larger in size. This could be explained on the basis that these wild cats are powerful and eat their prey by cutting into manageable pieces.