Ecological niche of organism includes the physical space occupied by it, its functional role in the community and the condition of existence. Ecological pyramids are the graphic representation of the trophic structure which function at successive trophic levels of an ecosystem. The complex of several communities in any area represented by an assemblage of different kind of plants, animals, etc. sharing a common climate is known as biome. The zone of transition presenting a situation of special ecological interest between two different types of communities is known as ecotone.