Question

What is pyramid of numbers? why does the number of organisms usually decrease at each trophic level?

Answer 1

Dear student

Pyramid of number- It represents total number of individuals of different species at each trophic level. It is upright when number of individuals is decreased from lower to higher trophic level. This type of pyramid is generally followed in grassland and pond ecosystem.

The number of individuals decreases as we move from a lower trophic level to a higher trophic level because autotrophs present in large numbers per unit area support a less number of herbivores, which in turn support even a lesser number of carnivores. So, the producers are maximum in number while top carnivores are largest in number.
Regards