Comprehension:
An ecosystem is a structural and functional unit of nature, which comprises of both abiotic (e.g., air, water, soil) and biotic (e.g., producers, consumers, decomposers) components. Productivity, decomposition, energy flow and nutrient cycling are four key important processes in an ecosystem. Primary productivity is rate of capture of solar energy or biomass production by producers. The energy flow is unidirectional and plants can utilize only 1% of available solar energy and energy is transferred among trophic level, following 10% law. The rate of capture of solar energy or total production of biomass by producers is called as gross primary productivity. The energy left after utilisation by producers is called as net primary productivity. Rate of assimilation of food energy by the consumers is referred as secondary productivity. Decomposition processes such as fragmentation of detritus, leaching and catabolism are responsible for converting detritus into CO2, H2O and inorganic nutrients.
Which of the following is not primarily/ directly associated with producers in an ecosystem?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Secondary Productivity
As the passage states, secondary productivity is the rate of assimilation of food energy by the consumers. It therefore belongs to the heterotrophic levels of the ecosystem, not to the producers.
Primary production, gross primary productivity and net primary productivity are all measures of the energy captured and the biomass built up by the producers themselves.