Assertion (A): | In secondary succession, climax is reached more quickly |
Reason (R): | The rate of succession is much faster than primary succession. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |
A | Primary productivity | (i) | Mass of living matter at a particular time |
B | Standing crop | (ii) | Organic matter formed by consumers |
C | Secondary productivity | (iii) | Is occupied by trees |
D | Top level in stratification | (iv) | Due to producers |
A | B | C | D | |
1. | (i) | (iv) | (ii) | (iii) |
2. | (iv) | (i) | (ii) | (iii) |
3. | (iv) | (i) | (iii) | (i) |
4. | (i) | (ii) | (iii) | (iv) |
1. | All the steps in decomposition operate simultaneously on the humus. |
2. | Humus is dark colored amorphous substance |
3. | Humus undergoes decomposition at very slow rate |
4. | Humus serves as reservoir of nutrients. |
1. | Humus is degraded by microbes to release inorganic nutrients whereas in later water soluble inorganic nutrients go down into the soil horizon. |
2. | Detritus is broken down whereas in later humus is degraded |
3. | Water soluble inorganic nutrients go down in soil and in later detritus is degraded by detrivores |
4. | Humus becomes colloidal and in later humus becomes detritus. |
1. | Carnivores | - | Secondary or tertiary consumer |
2. | Herbivores | - | Primary consumer |
3. | Decomposers | - | Microbial heterotrophs |
4. | Detrivores | - | Secondary consumers |
I: | The annual net primary productivity of the whole biosphere is approx 170 billion tons of organic matter. |
II: | Majority of this is contributed by the oceans as they occupy about 70 percent of the surface. |