Consider the following two statements:
l. | The annual net primary productivity of the whole biosphere is approximately 170 billion tons (dry weight) of organic matter. |
ll. | Majority of this is contributed by the oceans as they occupy larger area of earth. |
1. Both l and ll are correct and ll explains l
2. Both l and ll are correct but ll does not explain l
3. l is correct but ll is incorrect
4. l is incorrect but ll is correct
The second trophic level in a lake is:
1. Phytoplankton
2. Zooplankton
3. Benthos
4. Fishes
The limitations of ecological pyramids include all the following except:
1. The do not take into account the same species belonging to two or more trophic levels
2. They do not represent relationships between organisms at different trophic levels
3. They assume a simple food chain and do not consider food webs
4. Saprotrophs are not given any place in the ecological pyramids
Most food chains are composed of
1. 1 or 2 species
2. 3 or 4 species
3. 9 or 10 species
4. More than 16 species
Vertical distribution of different species occupying different levels in a biotic community is
known as
1. divergence
2. stratification
3. zonation
4. pyramid
The mass of living material at a tropic level at a particular time is called
1. Gross primary productivity
2. Standing state
3. Net primary productivity
4. standing crop
Which one of the following processes during decomposition is correctly described?
1. Fragmentation-Carried out by organisms such as earthworms
2. Humification-Leads to the accumulation of a dark-coloured substance humus, which
undergoes microbial action at a very fast rate
3. Catabolism-Last step in the decomposition under fully anaerobic condition
4. Leaching-Water soluble inorganic nutrients rise to the top layers of soil.
Which one of the following is not a functional unit of an ecosystem?
1. Energy flow
2. Decomposition
3. Productivity
4. Stratification
Which one of the following statements for pyramid of energy is incorrect, whereas the
remaining three are correct ?
1. It shows energy content of different trophic level organisms
2. It is inverted in shape
3. It is upright in shape
4. Its base is broad
Of the total incident solar radiation the proportion of PAR is
1. about 60%
2. less than 50%
3. more than 80%
4. about 70%