1. | A population | 2. | A species |
3. | A biological community | 4. | An ecosystem |
Energy flow and nutrient cycling are two important components of an ecosystem. What will be true comparison of the two?
1. | The amount of energy is much greater than the amount of nutrients |
2. | Organisms always need nutrients, but they don't always need energy |
3. | Nutrients are recycled, but energy is not |
4. | Organisms always need energy, but they don't always need nutrients |
1. | Stratification | 2. | Scarification |
3. | Standing crop | 4. | Standing state |
Productivity is the rate of production of biomass expressed in terms of :
i.
ii.
iii.
iv.
1. | ii | 2. | iii |
3. | ii and iv | 4. | i and iii |
In an ecosystem, the rate of production of organic matter during photosynthesis is called as its:
1. | Gross Primary productivity |
2. | Net Primary productivity |
3. | Secondary productivity |
4. | Non productivity |
Net primary productivity is the gross primary productivity minus:
1. | that which is consumed by herbivores |
2. | that which is consumed by the producer in metabolism |
3. | secondary productivity |
4. | loss due to mortality |
The annual net primary productivity of whole biosphere is approximately:
1. | 25 billion tons | 2. | 55 billion tons |
3. | 70 billion tons | 4. | 170 billion tons |
By process of leaching during decomposition of detritus, water soluble :
1. | organic nutrients go down the soil horizon and get precipitated as available salts |
2. | inorganic nutrients go down the soil horizon and get precipitated as unavailable salts |
3. | organic nutrients go down the soil horizon and get precipitated as available salts |
4. | inorganic nutrients go down the soil horizon and get precipitated as available salts |
The three steps of decomposition occur:
1. sequentially, with catabolism being the last step.
2. sequentially, with leaching being the last step.
3. simultaneously.
4. sequentially, but not in a particular order.
Decomposition of detritus is rapid when:
1. It is rich in lignin and chitin
2. Ambient temperature is low
3. Environment favours anaerobiosis
4. It predominantly contains nitrogen and sugars