Editing Fauna of Australia (section)

==Origins and history==
{{Main|Natural history of Australia}}
[[Image:Laurasia-Gondwana.png|thumb|Evidence suggests that Australia was a part of the supercontinent [[Gondwana]]]]
Both [[geology of Australia|geologic]] and climatic events helped to make Australia's fauna unique.<ref>Egerton, pp. 14, 20.</ref> Australia was once part of the southern supercontinent [[Gondwana]],<ref>Egerton, p. 20.</ref> which also included South America, Africa, India and Antarctica. Gondwana began to break up 140&nbsp;million years ago (MYA); 50 MYA Australia separated from Antarctica and was relatively isolated until the collision of the [[Indo-Australian Plate]] with Asia in the [[Miocene]] epoch 5.3 MYA. The establishment and [[evolution]] of the present-day fauna was apparently shaped by the unique climate and the geology of the continent. As Australia [[continental drift|drifted]], it was, to some extent, isolated from the effects of global climate change. The unique fauna that originated in Gondwana, such as the marsupials, survived and [[adaptive radiation|adapted]] in Australia.<ref>{{cite book |last1=Nowak |first1=Ronald M. |title=Walker's Marsupials of the World |date=2005 |publisher=JHU Press |isbn=978-0-8018-8211-1 |page=5 |url=https://books.google.com/books?id=ldXtY8ppxSQC&pg=PA5 |language=en}}</ref>

After the [[Miocene]], fauna of Asian origin were able to establish themselves in Australia. The [[Wallace Line]] — the hypothetical line separating the [[zoogeography|zoogeographical]] regions of Asia and Australasia — marks the tectonic boundary between the [[Eurasian Plate|Eurasian]] and Indo-Australian plates. This continental boundary prevented the formation of land bridges and resulted in a distinct zoological distribution, with limited overlap, of most Asian and Australian fauna, with the exception of birds. Following the emergence of the circumpolar current in the mid-[[Oligocene]] era (some 15 MYA), the Australian climate became increasingly arid, giving rise to a diverse group of arid-specialised organisms, just as the wet tropical and seasonally wet areas gave rise to their own uniquely adapted species.{{citation needed|date=November 2011}}