Ethology: The term Ethology was used by Isodore G.S. Hilare in 1859 for the study of relationship of organism within the family and society in the aggregate, and in the community.

Ecology: It is the science that studies inter-relationships between abiotic and biotic components on one hand, and among biotic components on the other hand.

Ecological niche: It is defined as the functional role and position (micro-habitat) of the species in its ecosystem, including what resources it uses, how and when it uses the resources, and how it interacts with other species.

Ecosystem: It is defined as a fundamental functional unit occupying spatial dimension of ‘earth space ship’ characterized by total assemblage of biotic community and abiotic components, and the mutual interaction within the given time unit.