Unit of productivity is :
[C] Both (a) and (b) . [D] None
[A] Available biomass for the consumption of heterotrophs
[B] Biomass produced by producers
[C] Gross primary product of respiratory losses [D] All of the above
The annual net primary productivity of the whole biosphere is how much billion tons (dry weight) of organic matter?
[C] 210 [D] 150
Oceans occupy ______ % of the surface of earth but productivity of ocean are ______ billion tons.
[C] 70, 55 [D] 60, 65
Productivity of ocean is less because:
[A] It occupies 70% of earth’s surface.
[B] Light is a major limiting factor which decreases with increase in water depth.
[C] It contains algae as a chief producer. [D] All of the above
What is the percentage of primary productivity of oceans?
[C] 32% [D] 70%
Earthworms help in:
[A] Breakdown of complex organic matter
[B] Loosening of soil
[C] Both (a) and (b) [D] None of the above
[A] Dead plant remains (leaves, bark and flower)
[B] Dead animal remains
[C] Fecal matter [D] All of the above
The important steps in the process of decomposition are:
[C] Catabolism [D] All of these
Match the columns:
1)Fragmentation A. Break down of detritus into smaller particles
2)Leaching B. Precipitation of water soluble nutrients as unavailable salt
3) Catabolism C. Degradation of detritus by bacterial and fungal enzymes
[B] 1-B, 2-C, 3-A
[C] 1-C,2-B,3-A [D] 1-C,2-A, 3-B
Which of these are true about humus?
[A] Dark colored amorphous substance
[B] Colloidal in nature
[C] Reservoir of nutrient [D] All of the above
Humus is degraded by some microbes and release of inorganic nutrients occur by the process known as ______.
[C] Humidification [D] Mineralization
Find out total number of incorrect statements from the following:
(A) Decomposition is largely an anaerobic process.
(B) Fragmentation, leaching and Catabolism occur simultaneously on detritus.
(C) Vertical distribution of different species occupying different level is called stratification.
(D) Pond is a deep water body.
(E) The rate of decomposition is controlled by chemical composition of detritus and climatic factors.
[C] 3 [D] 4
Decomposition is favoured by:
[A] Warm and moist environment
[B] Rich amount of nitrogen and water soluble substance like sugar in detritus
[C] Aerobic environment [D] All of the above
Rate of decomposition process is decreased by:
[A] Aerobic environment
[B] Rich amount of lignin and chitin in detritus
[C] Worm and moist environment [D] All of the above