Question

When the number of organisms at successive levels is plotted, they assume the shape of a pyramid. This is called the pyramid of
A. Biomass
B. Number
C. Energy
D.None of the these

Answer 1

Hint: Each organism in a food chain occupies a specific trophic level and based on that level it receives energy for survival and also to multiply. The energy distribution of each respective trophic gives a shape to the food chain which ultimately forms a pyramid called energy pyramid.

Complete step by step solution:
Energy pyramid is a composite of all the trophic levels of the food chain arranged according to the amount of energy in each level. This pyramid helps to determine which organism consumes how much energy in each level.

These energy pyramids are of different types based on certain differences. Thus, the energy pyramids are of three types; pyramid of energy, pyramid of number and pyramid of biomass.

Pyramid of energy is always upright and it shows the amount of energy consumption in each trophic level. Both the trophic levels and amount of energy go in opposite directions i.e., as the levels increase, the energy consumption gets decreased.

Another type is the pyramid of biomass which is mostly seen in oceans where the net quantity of biomass generated is depicted. For example, zooplanktons feeding on phytoplanktons in oceans.

The pyramid of numbers is the pyramid showing the population in an ecosystem. The total number of organisms that are present in each level is very well shown in these kinds of pyramids.

Thus, the pyramid in which the number of organisms at successive levels is plotted is a pyramid of numbers. So the correct option is B. .

Note: Pyramid of number is also upright just like pyramid of energy but it highly depends on the survival of organisms which may fluctuate as seen in a detritus food chain where organisms at higher levels feed on dead plants or animals and their debris.