Environment

Every organism is a specialized unit. It Invariably depends upon the environment and other organisms for its existence. It either eats other organisms or is eaten up by others and competes with others for the necessities of life such as food, shelter and mate.

Survival requires group association. such association and inter-relationships of organisms and environment in general constitute the Science of Ecology. The word was coined by Ernst Haeckel in 1869 and is derived from two Greek words "oikos" meaning 'house, habitation or place of living' and "logos" meaning 'study'. The field of ecology deals with the influence of environmental factors on all the aspects of life such morphology, physiology, growth, distribution, behaviour and survival of the organisms.

All the external conditions that affect the life of organisms i their natural habitats aggregate to form the environment i.e. 'the surroundings' of an organism.

The environment has been classified into :

(a) Physical or Abiotic Environment : It is composed of external physical factors like temperature, humidity, water, minerals and gases etc..

(b) Living or Biotic Environment : It is composed of all the living components-plants, animals and micro-organisms.

All these constituents of environment are referred to as the environmental factors or ecological factors or simply as factors. A factor is defines as an ecological condition which directly or indirectly affects the growth and development and hence the life of an organism.

"Environmental Studies" is the scientific of the environmental system and the status of its inherent or induced changes on organism. It includes not only the study of physical and biological characters of the environment but also the social and cultural factors and the impact of man on the environment