Biology Problems for Class 12 on “Ecosystem – Structure and Function – 2”.
1. From where do autotrophs obtain energy?
a) Ecosystem
b) Sunlight
c) Heterotrophs
d) Zooplankton
Answer: b
Clarification: Sunlight is the main source of energy of autotrophs. These are the organisms (producers) that can produce their own food using light, water, carbon dioxide, or other chemicals.
2. The phytoplankton, zooplankton, and the fungi are components of which ecosystem?
a) Pond
b) Land
c) Desert
d) Terrestrial
Answer: a
Clarification: The phytoplankton, zooplankton, and the decomposers are components of a pond ecosystem. Phytoplankton is autotrophs; zooplanktons are heterotrophs while the fungi act as decomposers.
3. Who reuses the decomposed dead matter?
a) Zooplankton
b) Autotrophs
c) Heterotrophs
d) Flagellates
Answer: b
Clarification: The decomposers decompose and mineralize the organic dead matter. They break down this organic matter into simple components that are reused by autotrophs as their source of nutrition and energy.
4. Who consumes the autotrophic components?
a) Trees
b) Plant
c) Phytoplankton
d) Heterotrophs
Answer: d
Clarification: The autotrophic components are consumed by heterotrophs. A heterotroph (consumers) is an organism that cannot produce its own food and therefore derives its intake of nutrition from other sources.
5. What is the movement of energy towards the higher trophic levels and its distribution and loss as heat to the lower trophic levels in the environment?
a) Multi-directional
b) Bi-directional
c) Uni-directional
d) No direction
Answer: c
Clarification: The movement of energy from the higher trophic levels and its distribution and loss as heat to the lower trophic levels in the environment is unidirectional. It means the energy moves in one direction only that is from higher to the lower-most level.
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