The correct sequence in primary hydrarch succession in early seral stages would be:
1. | Submerged plant – Submerged free-floating plant – Reed swamp – Marsh meadow |
2. | Submerged free-floating plant – Submerged plant – Reed swamp – Marsh meadow |
3. | Submerged plant – Submerged free-floating plant – Marsh meadow – Reed swamp |
4. | Submerged free-floating plant – Reed swamp – Submerged plant – Marsh meadow |
Which of the following ecosystem characteristics that changes during succession is not correctly matched?
|
Characteristics |
Seral stages |
Climax |
1. |
Size of individuals |
Small |
Large |
2. |
Ecological niches |
Few, generalized |
Many, specialized |
3. |
Food chains and webs |
Simple |
Complex |
4. |
Efficiency of energy use |
High |
Low |
Assertion (A): | We generally undervalue the magnitude of ecosystem services that benefits us. |
Reason (R): | We do not attach a monetary value to the services of natural 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. |
Nitrogen is often a limiting nutrient in terrestrial ecosystems because:
1. | the percentage of nitrogen in the atmosphere is low |
2. | atmospheric nitrogen is primarily in the stratosphere |
3. | dinitrogen cannot be used directly by the organisms |
4. | there are regional fluctuations in nitrogen levels in the atmosphere |
A primary consumer amongst the following would be:
1. | an autotroph | 2. | a horse parasite |
3. | an oak tree parasite | 4. | a wolf |
Top predators are especially endangered primarily because:
1. The population size would be small
2. Their food requirement is huge
3. They are more prone to diseases
4. They are usually outcompeted by prey
What is the percent of atmospheric carbon dioxide that is fixed annually by photosynthesis?
1. 70%
2. 36%
3. 10%
4. 1%
Choose the correct chronological order [lowest to highest] of the production efficiency of the given animals:
1. | mammals, fish, insects | 2. | insects, fish, mammals |
3. | fish, insects, mammals | 4. | insects, mammals, fish |
A herbivore eats 4,000 J of plant material. 2200 J is indigestible and is eliminated as feces. 1,600 J are used in cellular respiration. What is the approximate production efficiency of this animal?
1. | 1% | 2. | 5% |
3. | 10% | 4. | 50% |
The productivity in an aquatic ecosystem is least likely to be limited by:
1. | nitrogen | 2. | carbon |
3. | phosphorus | 4. | iron |