Question

Define with examples, pyramids of number and biomass.

Answer 1

Pyramid of Numbers

It is generally upright with producers population (e.g., grass plants, phytoplankton) being the largest. Producers support fewer herbivores (e.g., Grasshoppers, zooplankton). The number of primary carnivores (e.g., frogs, smaller fish) is still smaller. The number of higher order carnivores is very small. However, if the producer is large-sized like a tree, the pyramid of numbers can be inverted or spindle-shaped. A tree may support many herbivorous birds that may carry a large number of parasites or feed one or two hawks.

Pyramid of Biomass

Pyramid of biomass is generally upright with maximum biomass present in producers followed by lesser biomass in herbivores and still small biomass in carnivores. Only $10-20\%$ biomass is transferred from lower trophic to its higher trophic level. However, inverted or spindle-shaped pyramid of biomass is found in aquatic habitats due to smaller biomass of phytoplankton at any time because its members have a short life span but very high reproductive potential.