The productivity in an aquatic ecosystem is least likely to be limited by:
1. | nitrogen | 2. | carbon |
3. | phosphorus | 4. | iron |
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% |
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 |
What is the percent of atmospheric carbon dioxide that is fixed annually by photosynthesis?
1. 70%
2. 36%
3. 10%
4. 1%
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
A primary consumer amongst the following would be:
1. | an autotroph | 2. | a horse parasite |
3. | an oak tree parasite | 4. | a wolf |
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 |
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. |
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 |