Difference between revisions of "Australasia" - New World Encyclopedia

From New World Encyclopedia
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==Physical geography==
 
==Physical geography==
[[Physical geography|Physiographically]], Australasia includes the Australian landmass (including [[Tasmania]]), New Zealand, and [[Melanesia]]: [[New Guinea]] and neighbouring islands north and east of Australia in the Pacific Ocean. The designation is sometimes applied to all the lands and islands of the Pacific Ocean lying between the [[equator]] and [[latitude]] 47° south.
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Physiographically, Australasia includes the Australian landmass (including [[Tasmania]]), New Zealand, and [[New Guinea]]. The independant country of Papua New Guinea also includes approximately 600 offshore islands.  
  
Most of Australia lies on the southern portion of the [[Indo-Australian Plate]], flanked by the [[Indian Ocean]] to the west and the [[Southern Ocean]] to the south.  Peripheral territories lie on the [[Eurasian Plate]] to the northwest, the [[Philippine Plate]] to the north, and in the Pacific Ocean – including numerous [[marginal sea]]s – atop the [[Pacific Plate]] to the north and east.
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===Australia===
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The name "Australia" is derived from the Latin Australis, meaning "of the South". Most of Australia lies on the southern portion of the Indo-Australian Plate, flanked by the [[Indian Ocean]] to the west and the Southern Ocean to the south.  Peripheral territories lie on the Eurasian Plate to the northwest, the Philippine Plate to the north, and in the Pacific Ocean – including numerous marginal seas – atop the Pacific Plate to the north and east. Australia has a total landmass of 7,686,850 square kilometer (3,074,740 square mile) on the Indo-Australian Plate, slightly smaller than the contiguous 48 states of the United States, and 25,760 kilometers (15,970 miles) of coastline.
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Tectonic uplift of mountain ranges or clashes between tectonic plates occurred in Australia's early history, when it was still a part of Gondwana.  Much of Australia is desert or semi-arid. Only the southeast and southwest corners of the continent have a temperate climate and moderately fertile soil.  The majority of Australia is desert or semi-arid erosion has heavily weathered Australia's surface, resulting it one of the flattest countries in the world. Australia also has the oldest and least fertile soils, and is the driest inhabited continent.
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===New Zealand===
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The name "New Zealand" originated from Dutch cartographers, who originally named the islands ''Nova Zeelandia'', after the Dutch province of Zeeland. James Cook, the British explorer, subsequently anglicised the name to New Zealand.
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New Zealand consists of two main islands, North Island and South Islands, (Te-Ika-a-Maui and Te Wai Pounamu in Māori) and a number of smaller islands. The total landmass is 268,680 square kilometres (103,738 sq mi), with approximately 15,134 km (9,404 mi) of coastline. The larger South Island is divided along its length by the Southern Alps, with Aoraki/Mount Cook at 3754 metres (12,320 ft) its highest peak.  The North Island is less mountainous, but is marked by volcanism including the active Mount Ruapehu (2797 m / 9177 ft).
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New Zealand is part of the continent of Zealandia which is 93% submerged and approximately half the size of Australia. Approximately 25 million years ago, a shift in plate tectonic movements pulled Zealandia apart.
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===New Guinea===
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''"New Guinea" (Nueva Guinea) was the name coined by the Spanish explorer Yñigo Ortiz de Retez, who in 1545 noted the resemblance of the people to those he had earlier seen along the Guinea coast of Africa.''
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New Guinea's landmass is about 309,000 square miles (800,000 square km)
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The island of New Guinea is part of the Australian Plate, known as Sahul, and once formed part of the super-continent Gondwana. Sahul separated from Antarctica about 96 million years ago after Gondwana began to break up approximately 140 million years ago.  New Guinea moved into the tropics, as it drifted north. The origin of most New Guinean and Australian fauna are closely linked.
  
 
==Human geography==
 
==Human geography==

Revision as of 17:29, 22 September 2007

Australasia

Australasia is a term used to describe a region of Oceania. The physical countries, islands or regions that comprise Australasia vary greatly, ranging from Australasia(Australia and New Zealand)[1] to Australasia, islands of the South Pacific, including Australia, New Zealand, New Guinea, and adjacent islands. The term is sometimes used to include all of Oceania (Oceania, in fact, contains four major traditions: Polynesia, Melanesia, Micronesia, and Australia.).[2] The most common and widely accepted definition for Australasia is Australia, New Zealand, and the island of New Guinea, which consist of the Indonesian provinces of Papua and Papua Barat (formerly West Irian Jaya) and the independent country of Papua New Guinea.

The term was coined by Charles de Brosses in Histoire des navigations aux terres australes (1756). He derived it from the Latin for "south of Asia" and differentiated the area from Polynesia (to the east) and the southeast Pacific (Magellanica). It is also distinct from Micronesia (to the northeast).

Physical geography

Physiographically, Australasia includes the Australian landmass (including Tasmania), New Zealand, and New Guinea. The independant country of Papua New Guinea also includes approximately 600 offshore islands.

Australia

The name "Australia" is derived from the Latin Australis, meaning "of the South". Most of Australia lies on the southern portion of the Indo-Australian Plate, flanked by the Indian Ocean to the west and the Southern Ocean to the south. Peripheral territories lie on the Eurasian Plate to the northwest, the Philippine Plate to the north, and in the Pacific Ocean – including numerous marginal seas – atop the Pacific Plate to the north and east. Australia has a total landmass of 7,686,850 square kilometer (3,074,740 square mile) on the Indo-Australian Plate, slightly smaller than the contiguous 48 states of the United States, and 25,760 kilometers (15,970 miles) of coastline.

Tectonic uplift of mountain ranges or clashes between tectonic plates occurred in Australia's early history, when it was still a part of Gondwana. Much of Australia is desert or semi-arid. Only the southeast and southwest corners of the continent have a temperate climate and moderately fertile soil. The majority of Australia is desert or semi-arid erosion has heavily weathered Australia's surface, resulting it one of the flattest countries in the world. Australia also has the oldest and least fertile soils, and is the driest inhabited continent.

New Zealand

The name "New Zealand" originated from Dutch cartographers, who originally named the islands Nova Zeelandia, after the Dutch province of Zeeland. James Cook, the British explorer, subsequently anglicised the name to New Zealand.

New Zealand consists of two main islands, North Island and South Islands, (Te-Ika-a-Maui and Te Wai Pounamu in Māori) and a number of smaller islands. The total landmass is 268,680 square kilometres (103,738 sq mi), with approximately 15,134 km (9,404 mi) of coastline. The larger South Island is divided along its length by the Southern Alps, with Aoraki/Mount Cook at 3754 metres (12,320 ft) its highest peak. The North Island is less mountainous, but is marked by volcanism including the active Mount Ruapehu (2797 m / 9177 ft).

New Zealand is part of the continent of Zealandia which is 93% submerged and approximately half the size of Australia. Approximately 25 million years ago, a shift in plate tectonic movements pulled Zealandia apart.

New Guinea

"New Guinea" (Nueva Guinea) was the name coined by the Spanish explorer Yñigo Ortiz de Retez, who in 1545 noted the resemblance of the people to those he had earlier seen along the Guinea coast of Africa.

New Guinea's landmass is about 309,000 square miles (800,000 square km) The island of New Guinea is part of the Australian Plate, known as Sahul, and once formed part of the super-continent Gondwana. Sahul separated from Antarctica about 96 million years ago after Gondwana began to break up approximately 140 million years ago. New Guinea moved into the tropics, as it drifted north. The origin of most New Guinean and Australian fauna are closely linked.

Human geography

Geopolitically, Australasia is sometimes used as a term for Australia and New Zealand together, in the absence of another word limited to those two countries. There are many organizations whose names are prefixed with "(Royal) Australasian Society" that are limited to just Australia and New Zealand.

Australasian Olympic Flag

In the past, Australasia has been used as a name for combined Australia/New Zealand sporting teams. Examples include tennis between 1905 and 1913, when Australia and New Zealand combined its best players to compete in the Davis Cup international tournament (and won it in 1907, 1908, 1909 and 1911), and at the Olympic Games of 1908 and 1912.

In speculative fiction or counterfactual historical analysis, it is used to describe an alternate history Australia and New Zealand which agreed to political union at Australian federation in 1901, rather than seeking divergent British Empire Dominion status in 1901 and 1907 respectively.

Anthropologists, although disagreeing on details, generally support theories that call for a Southeastern Asian origin of indigenous island peoples in Australasia and neighboring subregions.

Ecological geography

The Australasia Ecozone

The Australasian ecozone is an ecological region that is coincident, but not synonymous (by some definitions), with the geographic region of Australasia. The ecozone includes Australia, the island of New Guinea (including Papua New Guinea and the Indonesian province of Papua), and the eastern part of the Indonesian archipelago, including the island of Sulawesi, the Moluccan islands (the Indonesian provinces of Maluku and North Maluku) and islands of Lombok, Sumbawa, Sumba, Flores, and Timor, often known as the Lesser Sundas. The Australasian ecozone also includes several Pacific island groups, including the Bismarck Archipelago, Vanuatu, the Solomon Islands, and New Caledonia. New Zealand and its surrounding islands are a distinctive sub-region of the Australasian ecozone. The rest of Indonesia is part of the Indomalayan ecozone.

From a biological point of view, Australasia is a distinct region with a common evolutionary history and a great many unique plants and animals, some of them common to the entire area, others specific to particular parts but sharing a common ancestry. The long isolation of Australasia from other continents allowed it to evolve relatively independently, and makes it home to many unique families of plants and animals.

Australia and New Guinea are distinguished by their marsupial mammals, including kangaroos, possums, and wombats. The last remaining monotreme mammals, the echidnas and the platypus, are endemic to Australasia. Prior to the arrival of humans about 50,000 years ago, only about one-third of Australasian mammal species were placental.

The boundary between Australasia and Indomalaya follows the Wallace Line, named after the naturalist Alfred Russel Wallace who noted the differences in mammal and bird fauna between the islands either side of the line. The Islands to the west of the line, including Java, Bali, Borneo, and the Philippines share a similar fauna with East Asia, including tigers, rhinoceros, and apes. During the ice ages, sea levels were lower, exposing the continental shelf that links these islands to one another and to Asia, and allowed Asian land animals to inhabit these islands. Similarly, Australia and New Guinea are linked by a shallow continental shelf, and were linked by a land bridge during the ice ages. A group of Australasian islands east of the Wallace line, including Sulawesi, Halmahera, Lombok, Flores, Sumba, Sumbawa, and Timor, is separated by deep water from both the southeast Asian continental shelf and the Australia-New Guinea continental shelf. These islands are called Wallacea, and contain relatively few Australian or Asian mammals. While most land mammals found it difficult to cross the Wallace Line, many plant, bird, and reptile species were better able to make the crossing.

Australia, New Zealand, and New Caledonia are all portions of the ancient supercontinent of Gondwana, which started to break into smaller continents in the Cretaceous era, 130-65 million years ago. New Zealand broke away first, more than 80 million years ago, and Australia finally broke free from Antarctica about 45 million years ago. All the Australasian lands are home to the Antarctic flora, descended from the flora of southern Gondwana, including the coniferous podocarps and Araucaria pines, and the broadleafed southern beech (Nothofagus), and proteas (Proteaceae).

As Australia moved north into the desert latitudes, the continent became hotter and drier, and the soils poorer and leached of nutrients, causing the old Antarctic flora to retreat to the humid corners of the continent in favor new drought and fire tolerant flora, dominated by the Eucalyptus,Casuarina, and Acacia trees, and by grasses and scrub where the rainfall was too scarce to support trees. Presently Australia is the smallest continent, and also the driest continent and the flattest (lowest in elevation) continent.

Geology

The present distribution of Australasian plants and animals is partially a result of the geologic history of its land masses. Several of the land masses in the ecoregion are fragments of the ancient continent of Gondwana, while a number of smaller islands are of more recent volcanic or tectonic origin, and were never part of Gondwana.

New Guinea, Australia, and Tasmania, collectively known as Australia-New Guinea, Sahul, or Meganesia, are connected by a shallow continental shelf, and together form the largest fragment of Gondwana. The shallow continental shelf that presently separates the islands has served as a land bridge when sea levels were lower, most recently during the last ice age. New Guinea shares many families of birds and marsupial mammals with Australia. As the Indo-Australian Plate, which contains India, Australia, and the Indian Ocean floor in between, moved north, it collided with the Eurasian Plate, and the collision of the two plates pushed up the Himalayas, the Indonesian islands, and New Guinea's Central Range. The Central Range is much younger and higher than the mountains of Australia, so high that it is home to rare equatorial glaciers. New Guinea and Wallacea are part of the humid tropics, and many Indomalayan rainforest plants spread across the narrow straits from Asia, mixing together with the old Australian and Antarctic floras. Some botanists consider New Guinea and Wallacea to be part of the floristic province of Malesia, together with the other Indonesian islands and the Malay Peninsula, although Malesia is now mostly used to refer to only the Indomalayan side of the Wallace Line.

New Zealand and New Caledonia are the other former fragments of Gondwana in the region.

The island groups north and east of New Guinea and New Caledonia, including Bismarck Archipelago, Admiralty Islands, Solomon Islands and Vanuatu, were pushed up by the collision of the Australian plate with other oceanic plates. These islands, collectively known as the East Melanesian Islands, were colonized by plants and some animals from New Guinea and New Caledonia, and are considered part of the Australasian ecozone based on those affinities. Further north and east are the Pacific island groups of Micronesia, Fiji, and Polynesia, which are also of relatively recent volcanic origin, and constitute the separate Oceania ecozone, although they share many ecological affinities with Australasia.

Fauna

Bats were the only mammals of New Zealand until the arrival of humans. Birds adapted to ecological niches, such as grazers, insectivores, and large predators that have elsewhere been taken by mammals. New Zealand remained in the cool and humid latitudes, and lost many plant and animal families that were intolerant of its cool climate, including the araucarias and most proteas, as well as crocodiles and turtles.

Large reptiles, including crocodiles and huge monitor lizards (family Varanidae), like the Komodo Dragon (Varanus komodoensis), are ecologically important predators in Australia, New Guinea, and Wallacea.

There are 13 endemic bird families, including emus, cassowaries, kiwi, kagu, cockatoos, birds of paradise, and honeyeaters

Human impact

The arrival of humans to Australia and New Guinea 50-60,000 years ago brought dogs (dingos) to Australia, and dogs and pigs to New Guinea. Pigs and rats arrived on New Zealand with the first Polynesian settlers 800 years ago. The arrival of the first humans coincided with the extinction of much of the native megafauna (see Holocene extinction event). The arrival of Europeans brought a whole host of new animals and plants, including sheep, goats, rabbits and foxes, to Australasia, which have further disrupted the native ecologies; a great many Australasian plants and animals are presently endangered.


Ecozones
Afrotropic · Antarctic · Australasia · Indomalaya · Nearctic · Neotropic · Oceania · Palearctic

Economics

Demographics

Culture

References
ISBN links support NWE through referral fees

  1. Commonwealth Encyclopedia Britanica. Oceania, Retrieved September 23, 2007.
  2. Australasia. The Columbia Electronic Encyclopedia, Sixth Edition. Retrieved September 22, 2007, from Answers.com Web site: http://www.answers.com/topic/australasia


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