Q. No.Nitrogen gas makes up nearly 80% of Earth's atmosphere, yet nitrogen is often a limiting factor for plant growth. Why ?
1. The atmospheric form of nitrogen cannot be used by plants.
2. Nitrifying bacteria remove usable nitrogen from the soil more repidly than plants can absorb it.
3. Atmospheric nitrogen dissolves readily in the soil but is washed out with every rainfall.
4. Plants must absorb nitrogen through their roots, which are not in contact with the atmosphere.
1. The atmospheric form of nitrogen cannot be used by plants.
2. Nitrifying bacteria remove usable nitrogen from the soil more repidly than plants can absorb it.
3. Atmospheric nitrogen dissolves readily in the soil but is washed out with every rainfall.
4. Plants must absorb nitrogen through their roots, which are not in contact with the atmosphere.
In general, the biomass in an ecosystem will be greatest at the trophic level comprising
1. secondary consumers
2. primary consumers
3. producers
4. tertiary consumers
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
What percent of energy in the sunlight availble to the primary producers is converted by them into net primary productivity ?
1. 1
2. 2
3. 5
4. 10
Both hydrach and xerarch successions:
1. Take same time
2. Have similar sere
3. Lead to mesic conditions
4. Have same pioneer species
The rate of formation of new organic matter by consumers is called as:
1. Secondary productivity
2. Standing crop
3. Standing state
4. Net primary productivity
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
About what percent of the global carbon is contained in the atmosphere?
1. 71
2. 49
3. 17
4. about 1
No predator can become proficient at acquiring prey because:
1. Predators are not as intelligent as prey.
2. Predators are too large to be fast enough.
3. Prey populations evolve more rapidly than predator populations.
4. Prey populations evolve anti-predatory traits.
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