Question

Net primary productivity is defined as?
A. Total amount of food stored by producers
B. Maximum available biomass of heterotroph consumption
C. Total amount of food stored by plants after herbivore consumption
D. Rate of formation of new organic matter by consumption

Answer 1

Hint: Primary productivity is defined as the rate at which organic matter is produced during photosynthesis. The production of autotrophs, such as plants, is called primary productivity, while secondary productivity is called the productivity of heterotrophs, such as animals.

Complete answer:
Net primary productivity can be defined as the amount of the food stored by the producer after some of the food is utilised by them in cellular activities. Net primary productivity includes the organic matter which remains from the total organic matter produced by the photosynthetic organisms.
Plants capture around 1.3% and 1.6% of the solar energy during the process of photosynthesis. 1% of solar energy becomes part of the net productivity of the plants.
Herbivores and carnivores are dependent on the plants to gain energy. They cannot capture and convert solar energy to produce organic biomass.
The amount of net productivity of the plant varies from ecosystem to ecosystem depending on the factors such as temperature, nutrient availability, water availability, and interaction with the community.
Apart from plants, algae and photosynthetic bacteria such as cyanobacteria contributed to the productivity in an ecosystem.
The rate of production of the new matter by consumption is called secondary productivity, and the efficiency at which transfer of energy occurs at each trophic level is called ecological efficiency.

Hence, the correct answer is option (A).

Note: Primary productivity is of two types; these types are gross productivity and net productivity. Gross production includes the total amount of organic matter produced, whereas net productivity includes the amount of organic matter that remained after using it by the producer.