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%

The biomass available for consumption by the herbivores and the decomposers is called

1. net primary productivity

2. secondary productivity

3. standing crop

4. gross primary productivity

Which one of the following is one of the characteristics of a biological community ?

1. Stratification 

2. Natality 

3. Mortality 

4. Sex-ratio

Which one of the following is not used for construction of ecological pyramids?

1. Dry weight

2. Number of individuals

3. Rate of energy flow

4. Fresh weight

Energy flow in an ecosystem is 

(1) unidirectional

(2) bidirectional

(3) multi-directional

(4) All the these