CHAPTER- 12: ECOSYSTEM
EXERCISES
1. Fill in the blanks.
(a) Plants are called as_________because they fix carbon dioxide.
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(b) In an ecosystem dominated by trees, the pyramid (of numbers)
is_________type.
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(c) In aquatic ecosystems, the limiting factor for the productivity
is_________.
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(d) Common detritivores in our ecosystem are_________.
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(e) The major reservoir of carbon on earth is_________.
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2. Which one of the following has the largest population in a food chain?
(a) Producers
(b) Primary consumers
(c) Secondary consumers
(d) Decomposers
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3. The second trophic level in a lake is
(a) Phytoplankton
(b) Zooplankton
(c) Benthos
(d) Fishes
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4. Secondary producers are
(a) Herbivores
(b) Producers
(c) Carnivores
(d) None of the above
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5. What is the percentage of photosynthetically active radiation (PAR) in
the incident solar radiation?
(a) 100%
(b) 50 %
(c) 1-5%
(d) 2-10%
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6. Distinguish between
(a) Grazing food chain and detritus food chain
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(b) Production and decomposition
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(c) Upright and inverted pyramid
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(d) Food chain and Food web
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(e) Litter and detritus
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(f) Primary and secondary productivity
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7. Describe the components of an ecosystem.
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8. Define ecological pyramids and describe with examples, pyramids of
number and biomass.
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9. What is primary productivity? Give brief description of factors that affect
primary productivity.
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10. Define decomposition and describe the processes and products of
decomposition.
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11. Give an account of energy flow in an ecosystem
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