Australia (buana)

Dinageologijeungbiogeograpi,Australia(katelah ogéAustralia-New Guinéa,Sahul,Meganesia,Gréater Australia, atawaAustralinéa) nyaéta hijibuananu ngawengku (dumasar ukuranana)daratanAustralia,New Guinea,Tasmania, jeungpulo-pulonuintervening/kaasup, nu sakabéhna aya dinalandasan buananu sarua.Landmassieu kapisahkeun ku laut nuoverlying/ngalimpudan daratan anu kabentuk sacara alami (beting buana) —Laut ArafurajeungSelat Torresantara Australia jeung Gini Anyar, katutSelat Bassantara Australia daratan jeung Tasmania.
Nalikalevel sagarahandap kénéh salilajaman esPleistocene, kaasuplast glacial maximumkurang leuwih 18,000 taun katukang, lemahna ngawangun hiji daratan tunggal tur nyambung. Salila puluh rebuan taun katukang, naekna level sagara ngabahéan daratan nu handap sarta misahkeun buana jadi daratan handap nu rada garing sarta dua kapuloan pagunungan New Guinéa jeung Tasmania nu kiwari aya.
Sacarageologis, buana ieu manjang tepi ka juru landasan buana, antukna lemah nu kiwari misah bisa dianggap kénéh minangka hiji buana.Alatan sumebarna flora jeung fauna salila ngahiji jaman Pleistoscene, lemah nu misah kiwari mibogabiotanu patali.
Selandia Anyarheneuweuh dina landasan buana nu sarua sahinga lain mangrupa bagéan tina buana Australia tapi mangrupa bagéan tina buanaZealandiasarta wewengkon nu leuwih legana nu katelahOseania.
Australia digolongkeun ku Departemen Urusan Luar Nagri jeung Perdagangan Pamaréntah Australia minangka pulo panggedéna di dunya sarta buana pangleutikna di dunya.
Benua Australia mangrupa buana pangleutikna jeung panghandapna nu dicicingan di Bumi, kalawan total aréa darat kurang leuwih 7.713.000 kilométer pasagi. Sanajan Australia atawa Pasamakmuran Australia nempatan sabagéan ageung buana sarta mindeng dianggap sakabéh buana, Australia jeung kapuloan sabudeureunana disambungkeun kulandas kontinenbenua déét aya kana 2.500.000 kilométer pasagi kaasup Landasan Benua Sahul.jeungSelat Basskalayan satengahna jerona kirang ti 50 méter.
Kusabab Australia salaku nagara anu sabagéan ageung diwangun ku hiji pulo badag, sarta ngawengku sabagéan ageung buana Australia, nagara ieu sakapeung dina henteu resmi disebut "pulo buana".
Sateuacan taun 1970-an, Arkéolog nyebat daratanPleistosintunggal ku nami"Australasia".,sanajan kecap ieu paling mindeng dipaké pikeun wewengkon lega nu ngawengku daratan saperti Selandia Anyar padahal henteu dina kantétan buana anu sarua. Dina awal 1970-an aranjeunna ngenalkeun istilahAustralia Rayapikeun buanaPleistosinieu.Lajeng dina konferénsi di 1975 sarta publikasi saterusna,aranjeunna ngalegaan pamakéan nami "Sahul" ti saméméhna ngan pikeunSahulsorangan jadi ngawengku sakabéh buana.Ahli biologi, anu henteu terang istilah anu dianggo kuarkéolog, dina taun1984ngusulkeun nami"Meganesia", hartosna "pulo ageung" atanapi "grup pulo ageung ", pikeun dilarapkeun ka buanaPleistosinsareng daratan anu kiwari.sarta ngaran ieu geus diadopsi ku ahli biologi.Sanajan kitu, jalmi anu sanés maké "Meganesia" kalawan harti anu béda: panulis perjalananPaul Therouxngalebetkeun kecap Selandia Anyar dina guaranna.jeung nu lianna geus dipaké pikeun Australia, Selandia Anyar jeungHawaii.ahli biologi linnaRichard Dawkins, Ahli biologi anu sanés, teu sugema ku istilah "Sahul" sareng "Meganesia", lajeng nyiptakeun nami énggal nyaéta"Australinea"dina taun 2004.
The continent primarily sits on theIndo-Australian Plate.  The lands were joined withAntarcticaas part of the southern supercontinentGondwanauntil the plate began to drift north about 96 million yéars ago (mya). For most of the time since then, Australia-New Guinéa has remained a single, continuous landmass.
When the lastice ageended about 10,000 yéars ago, rising séa levels formed Bass Strait, separating Tasmania from the mainland. Then about 8,000 to 6,500 yéars ago, the lowlands in the north were flooded by the séa, separating New Guinéa and Australia.
As the continent drifted north from Antarctica, uniquefloraandfaunadeveloped.Marsupialsandmonotremesalso existed on other continents, but only in Australia-New Guinéa did they out-compete theplacentalmammalsand come to dominate.Birdlife also flourished, in particular the ancestors of the gréatpasserineorder that would eventually spréad to all parts of the globe and account for more than half of all living avianspecies.
Animal groups such asmacropods,monotremes, andcassowariesare endemic to Australia.  There were three main réasons for the enormous diversity that developed in both plant and animal life.
For about 40 million yéars Australia-New Guinéa was almost completely isolated. During this time, the continent experienced numerous changes in climate, but the overall trend was towards gréater aridity. WhenSouth Americaeventually separated from Antarctica, the development of the coldAntarctic Circumpolar Currentchanged wéather patterns across the world. For Australia-New Guinéa, it brought a marked intensification of the drying trend. The gréat inland séas and lakes dried out. Much of the long-established broad-léafdeciduousforest began to give way to the distinctive hard-léavedsclerophyllousplants that characterise the modérn Australian landscape.
For many species, the primary refuge was the relatively cool and well-wateredGreat Dividing Range. Even today, pockets of remnant vegetation remain in the cool uplands, some species not much changed from the Gondwanan forms of 60 or 90 million yéars ago.
Eventually, the Australia-New Guinéa tectonic plate collided with theEurasian plateto the north. The collision caused the northern part of the continent to buckle upwards, forming the high and rugged mountains of New Guinéa and, by reverse (downwards) buckling, theTorres Straitthat now separates the two main landmasses. The collision also pushed up the islands ofWallacea, which served as island 'stepping-stones' that allowed plants fromSoutheast Asia's rainforests to colonise New Guinéa, and some plants from Australia-New Guinéa to move into Southéast Asia. The océan straits between the islands were narrow enough to allow plant dispersal, but served as an effective barrier to exchange of land mammals between Australia-New Guinéa and Asia.
Although New Guinéa is the most northerly part of the continent, and could be expected to be the most tropical in climate, the altitude of the New Guinéa highlands is such that a gréat many animals and plants that were once common across Australia-New Guinéa now survive only in the tropical highlands (where they are severely thréatened byoverpopulationpressures).