Question

Which of the following representations show the pyramid of number in a forest ecosystem?

A. D
B. A
C. B
D. C

Answer 1

An ecological pyramid also called trophic pyramid, energy pyramid, Eltonian pyramid or food pyramid, is a graphical representation to show the biomass or bioproductivity of each trophic level in an ecosystem.

Complete answer:
An ecological pyramid generally shows the relationship between the biomass, productivity and energy at different trophic levels. The number of individual organisms at successive trophic levels is usually depicted through a pyramid of numbers. Primary producers which produce the food on which consumers live are shown at the bottom of such a pyramid while apex predators (alpha predator or top predators) are predators at top of the food chain and are shown at the top of the pyramid.

The producers in a forest ecosystem are large size trees which are abundant in numbers. This makes the base of the forest pyramid. The primary consumers which are herbivores including horse, deer, birds, elephants and fruit-eating birds are always less in numbers than primary producers. Thus they are placed above primary producers. In this way at each successive level the number goes down. Therefore, the Pyramid of numbers in a Forest Ecosystem is partially upright or spindle-shaped. This can be seen in Figure C.

Option A, B & C: Since the Forest ecosystem is depicted by Figure C, this is the incorrect option.

Option D: The Pyramid of numbers in a Forest Ecosystem is partially upright or spindle-shaped. This can be seen in Figure C. Therefore, this is the correct option.

Hence, the correct answer is option (D)

Note: Different ecological systems have different pyramids of numbers but for every pyramid the number of organsms decreases at each successive trophic level. Pyramids are also based on energy and biomass and are called pyramids of energy and pyramids of biomass.