WORLD DISTRIBUTION OF LAND ANIMALS

WORLD DISTRIBUTION OF LAND ANIMALS The biosphere can be seen as a single distributional unit (representing the largest animal community) as far as global distribution of all animals is concerned. It can be sub­divided into two zoogeographical regions, e.g., (a) Land or terrestrial zoogeographical region; and (b) Aquatic (water) zoogeographical region. Zoogeographical regions are otherwise known as faunal regions.
The various facts worth. considering while studying the pattern of global distribution of animals are:
(a) That physical environmental conditions determine the number, abundance and diversity of animals;
(b) That there is zonal pattern in the global distribu­tion of animals and this occurs in two forms (i) horizontal zones, and (ii) vertical zones;
(c) That the animals have radiated in all directions from the centre of their origin. In other words, the distributional patterns of the world fauna are found in concentric zones;
(d) That the diversity of animals of a region is the result of serveral phases of their dispersal and colonisation;
(e) That the concentration of animals could be possible only in the mammals whereas the distribution of other animal species is more widespread and is not specific;
(f) That the distributional patterns of all the animal species are not uniform because the distribution of same animal species is continuous while that of other species is discontinuous or disjunct.
(g) That the oceanic islands are characterised by spe­cial types of animals as there has been minimum migration and dispersal of animals and plants to the islands because
of great oceanic barriers.

Several attempts have been made by scientists from time to time to categorise the world animals into faunal regions. However, A.R. Wallace's classification (done is 1876) still remains the most acceptable. Broadly there are six major faunal regions of the world: (a) Palaearctic, (b) Nearctic, (c) Oriental or Indomalaya, (d) Ethiopian, (e) Australian, and (f) Neotropical regions. These faunal re­gions are further divided into sub-regions and have their region-specific characteristic animals. (See box on page 94 for details).

India's Wildlife Like an extremely wide variety of flora (plants), India is also very rich in fauna (animals). There are about 81,000 known species dispersed across the country. The country has about 2,500 species of fresh and marine water fish. There are nearly 1,200 species of birds.