organisms

All the living organisms in area live in communities of plants and animales.They interect with their abiotic environment and wiht each other at different points in time for a large number of reasons.Life can exist only in a small portion of the Earth's land,water and its atmosphere .At global level the thin skin of Earth on the land ,the sea and the air forms the biosphere.
At a sub-global level ,this is devided in to biogeographical realms.For example,Eurisia is called the palearctric realm;south America forms the Neotropical realm;Africa the Ethiopiran realm;and Australia the Australian realm.
At a national or state level ,this forms niogeographic regions.There are several distinctive geographical regions in India-the Himalayas,the Gangetic plains,the highlands of Central India,the western and Eastern Ghats,the semi-arid desert in the west ,the Deccan plateau,the Coastal Belts,and the Andaman and Nicobar Islands.These geographically districtive areas have plants and animals that have been adapted to live in each of these regions.
At an even more local level,each area has several structurally identifiable ecosystems ,such as different types of forests,grasslands,river catchments mangrove swamps in deltas,seashores,islands etc..,to give just a few examples.Here too each of these forms a habitat for specific plants and animals.