Ecosystem Productivity and Energy Flow — NEET Biology
📚 Practice ConceptProductivity, decomposition, energy flow, and nutrient cycling are the four important components of an ecosystem. Primary productivity is the rate of capture of solar energy or biomass production of the producers. It is divided into two types: gross primary productivity (GPP) and net primary productivity (NPP). Rate of capture of solar energy or total production of organic matter is called as GPP. NPP is the remaining biomass or the energy left after utilisation of producers. Secondary productivity is the rate of assimilation of food energy by the consumers. In decomposition, complex organic compounds of detritus are converted to carbon dioxide, water and inorganic nutrients by the decomposers. Decomposition involves three processes, namely fragmentation of detritus, leaching and catabolism.
Match the following: Column I (Productivity Type) A. Gross Primary Productivity (GPP) B. Net Primary Productivity (NPP) C. Secondary Productivity D. Ocean Productivity Column II (Definition/Formula) 1. Rate of formation of new organic matter by consumers. 2. Total organic matter produced by autotrophs during photosynthesis. 3. GPP minus respiration losses (R). 4. Total biomass production from marine autotrophs. Column III (Key Characteristic/Significance) i. Significantly lower than terrestrial productivity despite vast area. ii. Represents total photosynthetic output. iii. Provides available biomass to heterotrophs. iv. Involves assimilation of food energy by non-producers.
View solution & NCERT explanation
Correct answer: A — A-2-ii, B-3-iii, C-1-iv, D-4-i
The core concept tested is the definition and characteristics of various types of productivity, including their ecological significance and comparisons. A. Gross Primary Productivity (GPP): This is the rate of production of organic matter during photosynthesis. It represents the total photosynthetic output. So, A-2-ii. B. Net Primary Productivity (NPP): This is GPP minus respiration losses (R). It represents the available biomass for consumption by heterotrophs. So, B-3-iii. C. Secondary Productivity: This is the rate of formation of new organic matter by consumers, involving the assimilation of food energy by non-producers. So, C-1-iv. D. Ocean Productivity: This refers to the total biomass production from marine autotrophs. Despite occupying about 70 percent of the surface, its productivity (55 billion tons) is significantly lower than land productivity (115 billion tons), often due to nutrient limitation. So, D-4-i. Therefore, the correct match is A-2-ii, B-3-iii, C-1-iv, D-4-i. The final answer is A.
What does NCERT say about Productivity decomposition energy flow?
Has this concept appeared in NEET?
Which chapter is this from?
Through deep analysis of NEET and NTA, 176 of the 180 ReNEET 2026 (June 21) questions were already in the MedicNEET question bank before the exam.
176/180MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.