Question

Which is not a natural ecosystem?
(a) Desert
(b) Aquarium
(c)Forest
(d) All of the above

Answer 1

Hint: An ecosystem is a functional unit of nature where all the biotic or living and abiotic or non-living components interact with each other in a specified volume of space. Every ecosystem has biotic or living and abiotic or non-living components. A natural ecosystem can exist without any planned manipulations by humans.

Complete answer:
An ecosystem is of two types- Natural ecosystem and artificial ecosystem. In the natural ecosystem, biotic and abiotic components freely interact with each other without any human interference. .E.g. Desert, Forest, Ocean. An artificial ecosystem is maintained artificially by humans who try to control the biotic community as well as the physicochemical environment. E.g. Aquarium, Crop fields.

Additional Information:
 The natural ecosystem is further classified into the terrestrial and aquatic ecosystem. The terrestrial ecosystem includes forest, grasslands and desert. A forest is an ecosystem with a high density of trees and other woody vegetation. Grasslands ecosystems occur in regions where soil water availability is dry enough for forests to thrive but can support the growth of herbaceous plant canopies. Desert ecosystem receives an extremely low amount of precipitation.
Aquatic ecosystems are distinguished as freshwater and marine ecosystems. A freshwater ecosystem can be lotic( running water such as a river) or lentic( standing water such as a lake). The marine ecosystem is the biggest ecosystem on earth. It refers to the aquatic ecosystem containing saltwater. E.g. Ocean, sea.
Greater genetic diversity and complex food chains are observed in a natural ecosystem along with an effective and natural nutrient cycling. But an artificial ecosystem requires continuous nutrient input from human beings for its maintenance. Like in aquariums the fishes need to be continuously fed and water needs to be regularly changed.
So, the correct answer is ‘Aquariums.’

Note:
 -Biotic components are developed from the biosphere while non-biotic components are developed from the hydrosphere, atmosphere, and lithosphere.
-Biotic components include autotrophs, heterotrophs and decomposers. Abiotic components include organic substances, inorganic substances and climatic factors.
-The life of living organisms depends on abiotic factors as they directly affect their growth, survival, and reproduction.