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Question
Write a short note on pyramid of numbers and pyramid of biomass.
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Solution
Pyramid of Number
- Pyramid of number deals with number of individuals in a trophic level.
Pyramid of numbers in a grassland ecosystem. Only three top carnivores are supported in an ecosystem based on production of nearly 6 millions plants
- In Grassland ecosystem only 3 top carnivores are supported in an ecosystem based on production of nearly 6 million plants.
- Pyramid of number in grassland or forest or pond ecosystem is upright.
- In parasitic food chain, the pyramid of number is inverted.
- In an ecosystem dominated by trees, the pyramid of number shaped/inverted.
- Among the grassland, pond and forest ecosystem, the number of primary producers per unit area would be maximum in the pond ecosystem.
Pyramid of Biomass
- Total amount of living material at various trophic level of a food chain is depicted by pyramid of biomass.
Pyramid of biomass shows a sharp decrease in biomass at higher trophic levels
- In most of the ecosystem, the pyramids of number and biomass are upright.
- In terrestrial ecosystem pyramid of biomass is generally upright.
- The pyramid of biomass in the sea or lake is generally inverted because the biomass of fishes exceeds that of phytoplankton.
Inverted pyramid of biomass-small standing crop of phytoplankton supports large standing crop of zooplankton
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