Question

Upright Pyramid of number is absent in:
a. Grassland
b. Forest
c. Pond
d. Lake

Answer 1

Hint: Ecological pyramids show the number of organisms at each trophic level. There are different types of ecological pyramids. Pyramid of number or number pyramid, pyramid of biomass or biomass pyramid, pyramid of energy or energy pyramid.

Complete answer:
Ecological pyramids represent the relationship of different organisms present in the ecosystem. The base of the pyramid is the broadest having plants. Each bar that makes up the pyramid is called trophic level. Based on the flow of energy, ecological pyramids are upright. Only 10% of energy moves to each trophic level. Rest of the energy is lost in surroundings. Ecological pyramids are the best way to represent the number of organisms in a food chain or food web. The width of the bar should be proportionate to the quantity of the organisms. Height of each bar should be the same.

Pyramid of numbers:
It shows the relationships between producers, herbivores and carnivores at successive trophic levels in terms of their numbers. For example, in grassland, the producers which are mainly grasses are always more in number. This number goes on reducing from base to the apex of the pyramid. The primary consumers as rabbits, mice etc. are lesser than the number of grasses. As we go in upward direction i.e. to secondary, tertiary / top level consumers hawk or other birds, their number will be least. Thus, the pyramid is upright.

The pyramid of numbers is not always upright. For example- the tree/forest ecosystem has partially inverted pyramids or more like spindles. The parasitic ecosystem has inverted the pyramid of numbers. Therefore, exceptions do exist in the pyramid of numbers.

A single oak tree has a large number of caterpillars, the caterpillars are eaten by bird tits which are eaten by sparrow hawks. Hence it forms a partially inverted pyramid.

A single large host can be home to different parasites, that act as food for many abundant hyper parasites.

Hence, The correct answer is option (B).

Note: The quantitative data of the organisms can be represented through ecological pyramids. The number, biomass and energy can be represented. In case of ecological pyramids although most of them are upright yet exceptions do exist.