Question

The upright pyramid of number is absent in
(a) Lake
(b) Forest
(c) Grassland
(d) Aquatic

Answer 1

Hint: This type of pyramid is absent in an ecosystem that has less number of producers in comparison to the primary consumers or the producers.

Complete answer:
The term pyramid of numbers indicates the number of individuals at different trophic levels in an ecosystem. It is upright in the lake ecosystem, grassland ecosystem, and aquatic ecosystem. But it is of spindle shape in a forest ecosystem. Because producers are mainly large trees which are less in number as compared to primary consumers such as birds, deer, elephants, etc. At the next trophic level, again the number of consumers gradually decreases from primary consumers to secondary consumers and secondary consumers to the tertiary or top consumers.

Additional Information:
Visualizing the structure of ecosystems with ecological pyramids was first described by the pioneering studies of Charles Elton in the 1920s. Ecological pyramids show the relative amounts of various parameters, that is, the number of organisms, energy, and biomass across the trophic levels. These pyramids can also be termed trophic pyramids or energy pyramids.
Depending on the ecosystem, the pyramids of numbers can be either upright or inverted. In a temperate forest, during the summer the base of the pyramid consists of few trees compared with the number of primary consumers, mostly insects. Because trees are large, they have great photosynthetic capability and are dominating other plants in this ecosystem to obtain sunlight.
So, the correct answer is,’ Forest’.

Note: -The amount of energy converted into living tissue at the different trophic levels is measured by a pyramid of biomass.
-An inverted biomass pyramid is found in the English Channel ecosystem because the primary producers make less biomass than the primary consumers.
-To show the energy flow through the trophic levels pyramid ecosystem modeling can also be used. since energy decreases at each trophic level the pyramids of energy are always upright.