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| Color-coded map
showing the various continents. Similar shades
exhibit areas that may be consolidated or
subdivided. |
Continents
A continent is one of several very large landmasses on
Earth. Generally identified by convention rather than
any strict criteria, up to seven regions are commonly
regarded as continents. Ordered from largest in size to
smallest, they are: Asia, Africa, North America, South
America, Antarctica, Europe, and Australia.
Geologically the continents largely correspond to areas
of continental crust that are found on the continental
plates. However some areas of continental crust are
regions covered with water not usually included in the
list of continents. The area referred to as Zealandia is
one such area (see submerged continents below).
Islands are frequently grouped with a neighbouring
continent to divide all the world's land into
geopolitical regions. Under this scheme, most of the
island countries and territories in the Pacific Ocean
are grouped together with the continent of Australia to
form a geopolitical region called Oceania. |
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| Comparison of area
(by tens of millions of square kilometres) and
population (by billions of people). |
Definitions and application
By convention, "continents are understood to be large,
continuous, discrete masses of land, ideally separated
by expanses of water." Several of the seven
conventionally recognized continents are not discrete
landmasses separated completely by water. The criterion
"large" leads to arbitrary classification: Greenland,
with a surface area of 2,166,086 square kilometres
(836,330 sq mi) is considered the world's largest
island, while Australia, at 7,617,930 square kilometres
(2,941,300 sq mi) is deemed the smallest continent.
Earth's major landmasses all have coasts on a single,
continuous World Ocean, which is divided into a number
of principal oceanic components by the continents and
various geographic criteria. The continents of Earth
include the following: Africa, Antarctica, Asia,
Australia, Europe, North America, and South America. |
- The seven-continent model is usually
taught in China, India, Pakistan, the Philippines, parts
of Western Europe and most English-speaking countries,
including Australia and the United Kingdom.
- The six-continent combined-Eurasia
model is mostly used in Russia, Eastern Europe, and
Japan.
- The six-continent combined-America
model is often used in France and its former
possessions, Italy, Portugal, Spain, Romania, Latin
America, and Greece.
- A five-continent model is obtained
from this model by excluding Antarctica as uninhabited.
This is used, for example in the United Nations and in
the Olympic Charter.
|
The term Oceania refers to a group of island countries and
territories in the Pacific Ocean, together with the
continent of Australia. Pacific islands with ties to other
continents (such as Japan, Hawaii or Easter Island) are
usually grouped with those continents rather than Oceania.
This term is used in several different continental models
instead of Australia.
Continents not only move but also sometimes move against
each other. The Indian subcontinent has been colliding with
the Eurasian continent for a while now. As these continents
push against each other, they buckle and bend. Because of
this, the Himalaya Mountains, where Mount Everest is, are
still being made today. |
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| The supercontinent
Pangaea in the early Mesozoic (at 200 Ma). |
Other divisions
Supercontinents
Aside from the conventionally known continents, the
scope and meaning of the term continent varies.
Supercontinents, largely in evidence earlier in the
geological record, are landmasses that comprise more
than one craton or continental core. These have included
Laurasia, Gondwana, Vaalbara, Kenorland, Columbia,
Rodinia, and Pangaea.
Subcontinents
Certain parts of continents are recognized as
subcontinents, especially the large peninsulas separated
from the main continental landmass by geographical
features. The most notable examples are the Indian
subcontinent and the Arabian Peninsula. The southern
cone of South America and Alaskan peninsula of North
America are other examples.
In many of these cases, the "subcontinents" concerned
are on different tectonic plates from the rest of the
continent, providing a geological justification for the
terminology. Greenland, generally reckoned as the
world's largest island on the northeastern periphery of
the North American Plate, is sometimes referred to as a
subcontinent. This is a significant departure from the
more conventional view of a subcontinent as comprising a
very large peninsula on the fringe of a continent.
Where the Americas are viewed as a single continent
(America), it is divided into two subcontinents (North
America and South America) or three (with Central
America being the third). When Eurasia is regarded as a
single continent, Europe is treated as a subcontinent.
Submerged continents
Some areas of continental crust are largely covered by
the sea and may be considered submerged continents.
Notable examples are Zealandia, emerging from the sea
primarily in New Zealand and New Caledonia, and the
almost completely submerged Kerguelen Plateau in the
southern Indian Ocean.
Microcontinents
Some islands lie on sections of continental crust that
have rifted and drifted apart from a main continental
landmass. While not considered continents because of
their relatively small size, they may be considered
microcontinents. Madagascar, the largest example, is
usually considered an island of Africa but has been
referred to as "the eighth continent" from a .
Botanical continents
"Continents" may be defined differently for specific
purposes. The Biodiversity Information Standards
organization has developed the World Geographical Scheme
for Recording Plant Distributions, used in many
international plant databases. This scheme divides the
world into nine "botanical continents". Some match the
traditional geographical continents, but some differ
significantly. Thus the Americas are divided between
Northern America (Mexico northwards) and Southern
America (Central America and the Caribbean southwards)
rather than between North America and South America.
The word continent
From the 16th century the English noun continent was
derived from the term continent land, meaning continuous
or connected land and translated from the Latin terra
continens. The noun was used to mean "a connected or
continuous tract of land" or mainland. It was not
applied only to very large areas of land—in the 17th
century, references were made to the continents (or
mainlands) of Isle of Man, Ireland and Wales and in 1745
to Sumatra. The word continent was used in translating
Greek and Latin writings about the three "parts" of the
world, although in the original languages no word of
exactly the same meaning as continent was used. |
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