Approximately how much of the solar energy that falls on the leaves of a plant is converted to chemical energy by photosynthesis?
1. | Less than 1% | 2. | 2-10 % |
3. | 30 % | 4. | 50 % |
How much of the net primary productivity of a terrestrial ecosystem is eaten and digested by herbivores?
1. | 1% | 2. | 10% |
3. | 40% | 4. | 90% |
Among the following bio-geo-chemical cycles, which one does not have losses due to respiration?
1. Phosphorus
2. Nitrogen
3. Sulphur
4. All of the above
The sequence of communities of primary succession in water is :
1. | Phytoplankton, sedges, free-floating hydrophytes, rooted hydrophytes, grasses, and trees. |
2. | Phytoplankton, free-floating hydrophytes, rooted hydrophytes, sedges, grasses, and trees. |
3. | Free-floating hydrophytes, sedges, phytoplankton, rooted hydrophytes, grasses, and trees. |
4. | Phytoplankton, rooted submerged hydrophytes, floating hydrophytes, reed swamp, sedges, meadow, and trees. |
Which of the following type of ecosystem is expected in an area where evaporation exceeds precipitation, and mean annual rainfall is below 100 mm?
1. Grassland
2. Shrubby forest
3. Desert
4. Mangrove
The zone at the edge of a lake or ocean which is alternatively exposed to air and immersed in water is called?
1. | Pelagic zone | 2. | Benthic zone |
3. | Lentic zone | 4. | Littoral zone |
Which of the following is an ecosystem service provided by a natural ecosystem?
1. | Cycling of nutrients |
2. | Prevention of soil erosion |
3. | Pollutant absorption and reduction of the threat of global warming |
4. | All of the above |
Assertion (A): | Various adaptations have evolved in plants that can increase their uptake of nutrients. |
Reason (R): | Plants are unable to ‘choose’ their environment as they are unable to move about. |
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. |
Assertion (A): | Most of an ecosystem’s production is eventually consumed by detritivores and decomposers. |
Reason (R): | Energy is said to flow through, not cycle within, ecosystems. |
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. |
Assertion (A): | Most food chains or webs have only about four or five trophic levels. |
Reason (R): | Trophic efficiencies are generally only about 10% in different ecosystems. |
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. |