Question

Total energy fixed by an ecosystem is
(a)Primary production
(b)Gross production
(c)Net production
(d)Secondary production

Answer 1

It is related to total production. Whereas the net production is the amount of biomass that is left for consumption by the consumers. When we talk about the word gross we account for everything in total.

Complete answer:
The total energy fixed in an ecosystem (by producers) in unit time is called Gross primary production. It includes organic matter used up in respiration. Therefore, it is known as Gross (total) production.

Additional Information:
- Gross primary production is the amount of total organic matter produced by plants (producers) during photosynthesis.
-Gross primary production is always more than net primary productivity.
-Gross productivity is always less than primary productivity.
PRIMARY PRODUCTION- Primary production is the amount of biomass or organic matter by plants during photosynthesis. It is of two types- Gross and Net primary productivity.
GROSS PRODUCTION- Gross production is the total energy captured or the total production of organic material during photosynthesis.
NET PRODUCTION- Net production is the balanced energy or biomass remaining after meeting the cost of respiration (by plants). It results in the accumulation of plant biomass, which serves as the food of herbivores and decomposers.
SECONDARY PRODUCTION- It is the biomass produced by consumers.
So, the correct answer is Gross production.

Note: Gross means total so it includes net production and respiratory losses. Always remember Gross production is more than Net production and Gross production is less than Primary production. Whereas the term secondary itself is self-explanatory and tells us that it is related to the second level (i.e., the consumers) and is the biomass produced by consumers.