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 residual, after autotrophic respiration is subtracted from GPP, is:
| 1. | secondary productivity | 2. | net primary productivity |
| 3. | standing crop biomass | 4. | chemosynthesis |
Energy and nutrients enter an ecosystem and hence in a community through:
1. Producers
2. Consumers
3. Detritivores
4. Apex predators
The prime driving force for the water cycle is:
| 1. | evapotranspiration from plants |
| 2. | rainfall |
| 3. | snowmelt |
| 4. | percolation of water through the soil |
The producers in aquatic ecosystems include all except:
| 1. | cyanobacteria | 2. | algae |
| 3. | plants | 4. | zooplankton |
Which of the following is most likely to exhibit the maximum difference between GPP and NPP?
1. phytoplankton in the ocean.
2. corn plants in a farmerʹs field.
3. prairie grasses.
4. an oak tree in a forest.
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