An ecosystem is a community of living organisms in conjunction with the non-living components of their environment (things like air, wider and mineral soil), interacting as a system. Ecosystem is a natural unit which consists of biotic communities and their abiotic environment. It is also Basic functional unit in ecology. Energy, water, nitrogen and soil  minerals are other essential abiotic components of an ecosystem. Ecosystem are controlled both by external and internal factors. External factors such as climate, parent material that forms the soil, typography, etc. and internal factors include disturbance, succession and the types of species present.

Characteristics of Ecosystem:

i) Biotic component: producer (green plants), consumers (animals), decomposers (microorganisms)

ii) Abiotic component: Air, water, soil

iii) Energy flow: Sun is the  main source of energy

iv) Matter

v) Interrelationship

vi) Biological integration

vii) Flexibility

viii) Ecological regulation

ix) Smallest unit of biosphere

x) An open system with a continuous, but variable influx and loss of materials and energy.