It refers to the total collection of living organisms of a geographic region.
The sum of abiotic and biotic components which have a direct or indirect influence on organisms is called environment. Generally, it refers to the surrounding of an object.
The term ecology was first coined by German Biologist, Ernst Haeckel in 1869. The word ecology is derived from two greek words 'Oikos' i.e. home or dwelling and 'logos' i.e. study. Thus, literally, ecology is the study of a household of nature. It is mainly concerned with the study of distribution and abundance of organisms, an interaction between the organisms, their interaction with the environment and the structure and function of a nation, ecosystem.
According to the Ernst Hackel, ecology is the scientific study of interactions of organisms with the components of the physical environment as well as with other organisms.
According to Odum, ecology is the scientific study of structure and function of nature.
According to Krebs(1985), ecology is the scientific study of interactions that determines the distribution and abundance of organisms.
There are mainly two branches of ecology;
Autoecology (Gr. Autos-self + ecology);
It deals with the study of interactions of single species with an environment. It is also called species ecology.
Synecology (Gr. Syn-together + ecology);
It deals with the study of interactions of various groups of organisms with their common environment. It is also called community ecology.
The components of the environment which have a direct or indirect influence on distribution, abundance, growth and development of living organisms are collectively called ecological factors or environmental factors. It is mainly categorized into two types:
Abiotic factors are non-living components of an environment which affect the organisms in various aspects. The abiotic factors are of different types:
Living organisms present in an environment which is constantly interacting with one another are called biotic factors. They include all plants, animals, microbes. The biotic factors are divided into two categories on the basis of their nutritional point of view. They are: