Australia,
officially the
Commonwealth of Australia, is a country in the
Southern Hemisphere comprising the mainland of the world's smallest
continent and a number of islands in the
Southern,
Indian, and
Pacific Oceans. Neighbouring countries include
Indonesia,
East Timor and
Papua New Guinea to the north, the
Solomon Islands,
Vanuatu and the
French dependency of
New Caledonia to the northeast, and
New Zealand to the southeast.
The mainland of the
continent of Australia has been inhabited for more than 42,000 years by
Indigenous Australians. After sporadic visits by fishermen from the north and by
European explorers and merchants starting in the seventeenth century, the eastern half of the mainland was claimed by the
British in 1770 and officially settled through
penal transportation as the
colony of
New South Wales on
26 January 1788. As the population grew and new areas were explored, another five largely
self-governing Crown Colonies were successively established over the course of the 19th century.
On
1 January 1901, the six colonies became a
Federation, and the Commonwealth of Australia was formed. Since federation, Australia has maintained a stable
liberal democratic political system and remains a
Commonwealth Realm. The capital city is
Canberra, located in the
Australian Capital Territory. The current national population is around 20.6 million people, and is concentrated mainly in the large coastal cities of
Sydney,
Melbourne,
Brisbane,
Perth, and
Adelaide.
The name Australia is derived from the
Latin Australis, meaning
of the South. Legends of an "unknown land of the south" (
terra australis incognita) dating back to Roman times were commonplace in mediaeval geography, but they were not based on any actual knowledge of the continent.
Australia consists of six states, two major mainland territories, and other minor territories. The states are
New South Wales,
Queensland,
South Australia,
Tasmania,
Victoria and
Western Australia. The two major mainland territories are the
Northern Territory and the
Australian Capital Territory. In most respects, the territories function similarly to the states, but the Commonwealth Parliament can override any legislation of their parliaments. By contrast, federal legislation overrides state legislation only with respect to certain areas as set out in
Section 51 of the
Constitution; all residual legislative powers are retained by the state parliaments, including powers over hospitals, education, police, the judiciary, roads, public transport and local government.
Australia's 7,686,850
square kilometres (2,967,909
sq. mi) landmass is on the
Indo-Australian Plate. Surrounded by the
Indian,
Southern and
Pacific oceans, Australia is separated from Asia by the
Arafura and
Timor seas. Australia has a total 25,760
kilometres (16,007
mi) of coastline and claims an extensive
Exclusive Economic Zone of 8,148,250 square kilometres (3,146,057 sq. mi). This exclusive economic zone does not include the
Australian Antarctic Territory.
The
Great Barrier Reef, the world's largest
coral reef, lies a short distance off the north-east coast and extends for over 2,000 kilometres (1,250
mi). The world's largest
monolith,
Mount Augustus, is located in Western Australia. At 2,228
metres (7,310
ft),
Mount Kosciuszko on the
Great Dividing Range is the highest mountain on the Australian mainland, although
Mawson Peak on the remote Australian territory of
Heard Island is taller at 2,745 metres (9,006 ft).
Although most of Australia is semi-
arid or
desert, it covers a diverse range of habitats, from alpine heaths to tropical
rainforests. Because of the great age and consequent low levels of fertility of the continent, its extremely variable weather patterns, and its long-term geographic isolation, much of Australia's
biota is unique and
diverse. About 85% of
flowering plants, 84% of
mammals, more than 45% of
birds, and 89% of in-shore, temperate-zone fish are
endemic.
[14] Many of Australia's ecoregions, and the species within those regions, are threatened by human activities and
introduced plant and animal species. The federal
Environment Protection and Biodiversity Conservation Act 1999 is a legal framework used for the protection of threatened species. Numerous
protected areas have been created under the country's
Biodiversity Action Plan to protect and preserve Australia's unique ecosystems, 64 wetlands are registered under the
Ramsar Convention, and 16
World Heritage Sites have been established. Australia was ranked thirteenth in the World on the 2005
Environmental Sustainability Index.
Most Australian woody plant species are evergreen and many are adapted to fire and drought, including many
eucalyptus and
acacias. Australia has a rich variety of endemic
legume species that thrive in nutrient-poor soils because of their symbiosis with
Rhizobia bacteria and
mycorrhizal fungi. Well-known Australian fauna include
monotremes (the
platypus and
echidna); a host of
marsupials, including the
kangaroo,
koala,
wombat; and birds such as the
emu, and
kookaburra. The
dingo was introduced by Austronesian people that traded with Indigenous Australians around 4000
BCE. Many plant and animal species became extinct soon after human settlement, including the
Australian megafauna; others have become extinct since European settlement, among them the
Thylacine.