Question

The storage of energy at the consumer level is known as
(a) Gross primary production
(b) Secondary productivity
(c) Net primary productivity
(d) Net productivity

Answer 1

Hint: The productivity of an ecosystem depends upon the energy present in organic matter. Storage of energy at the consumer level is the rate at which organic matter is built up by the consumer. The consumer obtains energy in a readymade form which gets produced by the producer lying lower to the consumer.

Complete answer:
Storage of energy at the consumer level is known as secondary productivity, which is the rate of organic matter built up by the consumer. A herbivore obtains readymade energy from the plants in which they use a fraction of plant matter for feeding, from which the remainder of ingested matter comes out in the form of feces which get decomposed by decomposers. Carnivores are more efficient than herbivores in converting food into biomass because they consume up to $60\%$ of organic matter in respiration whereas herbivores consume $30\%$ of energy in respiration.
The primary productivity is the rate of energy or biomass synthesized by the producer. A producer obtains energy by photosynthesis and it gets calculated per unit time per unit area. Primary productivity is divided into gross primary productivity and net primary productivity. Gross primary productivity is the total amount of energy that gets synthesized or produced by the producer during photosynthesis whereas net primary productivity is the amount of energy stored by the producer.

So, the correct answer is ‘Secondary productivity’.

Note:
In secondary productivity, new organic matter does not form, it only utilizes the food produced by primary producers. It also does not lead to the net gain of energy in the biosphere. Secondary productivity describes the energy flow that takes place through each trophic level.