Practice free Ecosystem (Botany) NEET multiple-choice questions online with instant answers and detailed explanations. No login required.
Secondary productivity is defined as the rate of formation of new organic matter by:
The NCERT defines secondary productivity as 'the rate of formation of new organic matter by consumers.' The summary further states, 'Secondary productivity is the rate of assimilation of food energy by the consumers.'
If an ecosystem's Gross Primary Productivity (GPP) is 1200 kcal $m^{-2}yr^{-1}$ and the respiration loss (R) by producers is 300 kcal $m^{-2}yr^{-1}$, what is the Net Primary Productivity (NPP)?
As per the formula provided in NCERT, NPP = GPP - R. Therefore, NPP = 1200 - 300 = 900 kcal $m^{-2}yr^{-1}$.
Which of the following units is commonly used to express productivity?
The NCERT states, 'It is expressed in terms of gm $^{-2}$ yr $^{-1}$ or (kcal $m^{-2}$) yr $^{-1}$ to compare the productivity of different ecosystems.' Options 1 and 2 represent standing crop or biomass, not the rate of production.
Productivity is one of the four important components of an ecosystem. The other three are:
The summary section of the NCERT chapter states, 'Productivity, decomposition, energy flow, and nutrient cycling are the four important components of an ecosystem.'
Which statement about Net Primary Productivity (NPP) is correct?
The NCERT explains, 'Gross primary productivity minus respiration losses (R), is the net primary productivity (NPP). GPP – R = NPP.' Also, 'NPP is the remaining biomass or the energy left after utilisation of producers.'
David Tilman's long-term ecosystem experiments using outdoor plots suggested that:
From the 'BIODIVERSITY AND CONSERVATION' chapter, it's mentioned that 'Tilman found that plots with more species showed less year-to-year variation in total biomass. He also showed that in his experiments, increased diversity contributed to higher productivity.'
Primary productivity varies in different types of ecosystems due to various factors. Which of the following is NOT specified as a key factor influencing it?
The NCERT states, 'Primary productivity depends on the plant species inhabiting a particular area. It also depends on a variety of environmental factors, availability of nutrients and photosynthetic capacity of plants.' Consumption by secondary consumers affects energy flow and biomass at higher trophic levels, not directly primary productivity.
Identify the correct statements:
A. Detrivores perform fragmentation. B. The humus is further degraded by some microbes during mineralization. C. Water soluble inorganic nutrients go down into the soil and get precipitated by a process called leaching. D. The detritus food chain begins with living organisms. E. Earthworms break down detritus into smaller particles by a process called catabolism.
D wrong (detritus food chain starts with DEAD organic matter); E wrong (earthworms perform fragmentation, not catabolism).
The thickness of ozone in a column of air in the atmosphere is measured in terms of:
Ozone column is measured in Dobson units (DU).
In the equation $GPP - R = NPP$, $R$ here is:
NPP = GPP − Respiratory loss (energy used by plant for respiration).
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