Write short note: Uniqueness of fauna in the Notogean realm. 2013 UPSC Geography Optional Mains Question.
Austral Realm/ Notogean Realm Evolution ; Biogeographical evolution is characterized by continental drifting and Orogenic changes Drifting : Australia was having Mediterranean and temperate deciduous vegetation. As it started drifting by breaking away from Antarctica in the early Cenozoic period, it came under the influence of cold West wind drift current, increasing the aridity of Australia. Orogeny : As it drifted further to the north and reached the sub-tropics, the orogeny of Great Dividing range started and its rain shadow effect converted a large part of Australia into desert from the temperate forest and Mediterranean vegetation . The Xerophytic vegetation and arid climatic conditions restricted the growth of Mammal families in Australia. Most of the mammals in Australia are believed to have come from outside via the Island bridges and settled there, undergone speciation, to attain the present form. All major mammals including Monotremes like Duck ...