The ecosystem term was coined by A.G. Tansley in 1935. It is an interrelationship between living and non-living components of an area in which the flow of matter and energy takes place. The ecosystem is a structural and functional unit of the biosphere.

A large-sized glass box with an aerating pump and light in which small-sized fish, plants, and other small creatures are reared in freshwater is known as an aquarium. It is an example of an artificial ecosystem.

The mode of nutrition in which organisms make food themselves from simple substances is called autotrophic nutrition. Therefore, plants are called autotrophs. Plants are autotrophs. They use the process of photosynthesis to transform water, sunlight, and carbon dioxide into oxygen, and simple sugars (glucose) that the plant uses as fuel.