Q. No.The earth is regarded as “open” system with respect to:
1.
organisms
2.
chemicals
3.
energy
4.
water
If decomposers go extinct on Earth:
| 1. | Detritivores will replace them |
| 2. | Primary production will increase |
| 3. | Nutrients will accumulate in dead plants and animals |
| 4. | There will be no effect on carnivores |
A chemical that enters living organisms primarily from the atmosphere is:
| 1. | phosphorus | 2. | sulfur |
| 3. | sodium | 4. | carbon |
What is the best description of trophic efficiency?
| 1. | the ratio of net secondary production to the assimilation of primary production. |
| 2. | the percentage of production transferred from one trophic level to the next. |
| 3. | a measure of how nutrients are cycled from one trophic level to the next. |
| 4. | usually greater than production efficiencies. |
What percent of the energy fixed by primary producers in a typical field ecosystem is received by a secondary consumer?
| 1. | 0.1% | 2. | 1% |
| 3. | 10% | 4. | 20% |
The rate at which energy is converted by photosynthetic and chemosynthetic autotrophs to organic substances is called as:
1. biomass
2. transpiration
3. net primary productivity
4. gross primary productivity
The chemical energy that is not converted to new biomass in the process of energy transfer between trophic levels in an ecosystem is finally:
1. removed in the feces
2. recycled by decomposers
3. used by heterotrophs to thermoregulate.
4. dissipated into space as heat
Aquatic ecosystems that are most adversely affected by acid are those that lack:
1. calcium
2. carbonic acid
3. nitrate
4. bicarbonate
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