Page 1 - Assignment-Ecosystem

Assignment

A – Multiple Choice Questions (MCQs)

1. At the trophic level of consumers, the rate at which food energy is assimilated, is
called:
1. Secondary productivity
2. Gross primary productivity
3. Net primary productivity
4. None of these
2. The term "detritivore" includes
1. decomposers
2. primary consumers
3. secondary consumers
4. Autotrophs
3. Net primary productivity is the gross primary productivity less
1. that which is consumed by herbivores
2. that which is consumed by producer in metabolism
3. secondary productivity
4. loss due to mortality
4. The major reservoir for phosphorous is
(a) Aquifers
(b) Soil and rocks
(c) The atmosphere
(d) Clouds
5. Which of the following pyramids can never be inverted in a natural ecosystem?
1. pyramid of numbers
2. pyramid of energy
3. pyramid of biomass
4. all can be inverted
6. The earth is an open system with respect to
1. organisms
2. chemicals
3. energy
4. all of the above
7. Which trophic level is incorrectly defined?
1. Carnivores- secondary or tertiary consumer
2. Decomposer- microbial heterotrophs
3. Herbivores - primary consumer
4. Omnivores - Molds, yeast and mushrooms
8. 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