Biocenosis and the biotope together form biogeocenosis.
The main part of biogeocenosis is called as biocenosis which is said to be different from each other by species composition.
It is an interrelated complex of living and inert components that are associated with each other by material and energy exchange among them.
The living components of the biogeocenosis are autotrophic organisms( which perform photosynthesis and some chemosynthesizing microorganisms) and heterotrophic organisms (animals, fungi, etc) and among the inert components is the atmosphere layer present around the earth, with its gas and the thermal resources and solar energy, soil water, and mineral resources.
Biogeocenosis maintains quite a uniformity of the composition and structure of its components as well as the character of the material and energy exchange taking place between them.