Question

Read the following statements (A-C) related to the functions of an ecosystem and identify the correct statements.

A. There is exchange of nutrients between the biotic and abiotic components of the ecosystem.
B. The abiotic components help in the synthesis of organic matter without input of energy.
C. Ecosystem regulates the essential ecological processes and supports life.

• A. A and B
• B. B and C
• C. A and C
• D. A, B and C

Answer 1

The correct option is C A and C

An ecosystem is a stable unit formed by the interactions between the biotic (living) and abiotic (non-living) components that are comprised in it.

The abiotic components include water, temperature, light, air and soil. The biotic components include producers, consumers and decomposers.

Ecosystems are the functional units of nature, and they perform various functions as follows:

• There is cycling of nutrients between the biotic and abiotic components. For example, carbon dioxide present in the air (abiotic component) is fixed by plants (biotic component) in the presence of sunlight and water. The food (sugars) synthesised by the plants through photosynthesis is available to the consumers. Hence, carbon from the atmosphere enters the biotic components (living organisms). When organisms respire, carbon dioxide is released back into the atmosphere. Also, upon the death of the organisms, the decomposers degrade the dead bodies of plants and animals and release the inorganic nutrients back into the environment. This is how the various elements like carbon, nitrogen, phosphorus are cycled in the biosphere between biotic and abiotic components. Hence statement A is correct.
• The abiotic components like water, carbon dioxide present in the air are used to produce starch in the presence of sunlight (energy) and chlorophyll by green plants. Here light energy (abiotic) is fixed as chemical energy in the form of starch in a biotic component (plants). Thus, the abiotic components help in the synthesis of organic matter with the input of energy. Hence statement B is incorrect.
• Ecosystem regulates the essential ecological processes (conversion of light energy to chemical energy by photosynthesis), supports life (by providing food) and renders stability. So, statement C is correct.