The study of interactions between the animals with their biotic and abiotic environment is called as ecology or ecological science. On the earth, every organism is adapted to the environment to survive i.e. become adapted to the environmental factors and to the inhabiting other plants and animal species.

Term “Ecology” is a Greek word which means — Oikos = House and Logos = Study. Here house indicates the habitat of the organism. Reiter (1868) was first to use the term Ecology. Ernst Hacked (1869), a German Scientist interpreted and defined the term ecology.

Definition :
Many scientists defined the ecology in different ways. Such as –

• Taylor (1936) : defined ecology as study of all organisms in relation with the environment.
• Philip Handler (1970) : stated that the study of relationship of organism and their environment is called as ecology.
• The study of relationship between living systems and environment is called ecological science (Turch and Witz, 1972).
• The ecology concerns with study of functioning living organisms and the environmental systems like land, oceans, fresh water bodies. Odum defined ecology as “study of structure and function of the nature”
• The leading ecologist of India, Ramdeo Misra (1968) defined ecology as study of interactions between shapes and functions of organisms and the factors.
  Hence to conclude, ecology can be define as “Study of interaction between living beings and their Environment.”