i) An ecosystem is self-sustaining system. Except energy (light) it does not require any thing from outside it.
ii) The system is capable of maintain itself because of the delicate but complex interactions of its biotic and abiotic components.
iii) Like human body, ecosystem has different parts that perform different functions for its survival.
iv) All natural ecosystems are stable. They maintain a state of balance called equilibrium.
v) If ecosystems are not balanced, they would not survive.
vi) An ecosystem gets its stability from the maze of interactions that link its parts. Vii) It is very difficult to understand every detail of how even simple ecosystems function.
viii) We understand that changes in one part of a system can trigger changes in other parts, but we cannot understand that how changes in one part of the ecosystem affect another part.
Role of man in disruption of natural balance:
i) At present, species are becoming extinct at the fastest rate since earth's known history. The cause of these extinctions is human activity.
ii) Human are disturbing the balance through pollution and deforestation, on global environment.