biogeography Biogeography is the study of the species distribution, distribution of species and ecosystems in geography, geographic space and through evolutionary history of life, geological time. Organisms and biological community (ecology), communities o ...

, a land bridge is an isthmus or wider land connection between otherwise separate areas, over which

animals Animals are multicellular, eukaryotic organisms in the biological kingdom Animalia (). With few exceptions, animals consume organic material, breathe oxygen, have myocytes and are able to move, can reproduce sexually, and grow from a ...

and

plant Plants are the eukaryotes that form the Kingdom (biology), kingdom Plantae; they are predominantly Photosynthesis, photosynthetic. This means that they obtain their energy from sunlight, using chloroplasts derived from endosymbiosis with c ...

s are able to cross and colonize new lands. A land bridge can be created by marine regression, in which

sea level Mean sea level (MSL, often shortened to sea level) is an mean, average surface level of one or more among Earth's coastal Body of water, bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical ...

s fall, exposing shallow, previously submerged sections of continental shelf; or when new land is created by

plate tectonics Plate tectonics (, ) is the scientific theory that the Earth's lithosphere comprises a number of large tectonic plates, which have been slowly moving since 3–4 billion years ago. The model builds on the concept of , an idea developed durin ...

; or occasionally when the sea floor rises due to

post-glacial rebound Post-glacial rebound (also called isostatic rebound or crustal rebound) is the rise of land masses after the removal of the huge weight of ice sheets during the last glacial period, which had caused isostatic depression. Post-glacial rebound an ...

after an

ice age An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages, and g ...

Prominent examples

Former land bridges

* The Bassian Plain, which linked

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

Tasmania Tasmania (; palawa kani: ''Lutruwita'') is an island States and territories of Australia, state of Australia. It is located to the south of the Mainland Australia, Australian mainland, and is separated from it by the Bass Strait. The sta ...

* The Antarctic Land Bridge, which connected South America, Antarctica, and Australia during the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

and Early

Paleogene The Paleogene Period ( ; also spelled Palaeogene or Palæogene) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period Ma (million years ago) to the beginning of the Neogene Period Ma. It is the fir ...

* The Bering Land Bridge (aka Beringia), which intermittently connected

Alaska Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...

(

Northern America Northern America is the northernmost subregion of North America, as well as the northernmost region in the Americas. The boundaries may be drawn significantly differently depending on the source of the definition. In one definition, it lies dir ...

) with

Siberia Siberia ( ; , ) is an extensive geographical region comprising all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has formed a part of the sovereign territory of Russia and its predecessor states ...

(

North Asia North Asia or Northern Asia () is the northern region of Asia, which is defined in geography, geographical terms and consists of three federal districts of Russia: Ural Federal District, Ural, Siberian Federal District, Siberian, and the Far E ...

) as sea levels rose and fell under the effect of ice ages * GAARlandia, a hypothesized land bridge which potentially connected the

Greater Antilles The Greater Antilles is a grouping of the larger islands in the Caribbean Sea, including Cuba, Hispaniola, Puerto Rico, and Jamaica, together with Navassa Island and the Cayman Islands. Seven island states share the region of the Greater Antille ...

with South America during the

late Eocene The Priabonian is, in the International Commission on Stratigraphy, ICS's geologic timescale, the latest age (geology), age or the upper stage (stratigraphy), stage of the Eocene epoch (geology), Epoch or series (stratigraphy), Series. It spans ...

early Oligocene The Rupelian is, in the geologic timescale, the older of two age (geology), ages or the lower of two stage (stratigraphy), stages of the Oligocene epoch (geology), Epoch/series (stratigraphy), Series. It spans the time between . It is preceded b ...

* Land bridges of Japan, several land bridges which connected Japan to Russia and Korea at various times in history * De Geer Land Bridge, a route that connected

Fennoscandia __NOTOC__ Fennoscandia (Finnish language, Finnish, Swedish language, Swedish and ; ), or the Fennoscandian Peninsula, is a peninsula in Europe which includes the Scandinavian Peninsula, Scandinavian and Kola Peninsula, Kola peninsulas, mainland ...

to northern

Greenland Greenland is an autonomous territory in the Danish Realm, Kingdom of Denmark. It is by far the largest geographically of three constituent parts of the kingdom; the other two are metropolitan Denmark and the Faroe Islands. Citizens of Greenlan ...

* Doggerland, a former landmass in the southern

North Sea The North Sea lies between Great Britain, Denmark, Norway, Germany, the Netherlands, Belgium, and France. A sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian Se ...

which connected the island of

Great Britain Great Britain is an island in the North Atlantic Ocean off the north-west coast of continental Europe, consisting of the countries England, Scotland, and Wales. With an area of , it is the largest of the British Isles, the List of European ...

continental Europe Continental Europe or mainland Europe is the contiguous mainland of Europe, excluding its surrounding islands. It can also be referred to ambiguously as the European continent, – which can conversely mean the whole of Europe – and, by som ...

during the last ice age * The Thule Land Bridge, a now-vanished land bridge between the

British Isles The British Isles are an archipelago in the Atlantic Ocean, North Atlantic Ocean off the north-western coast of continental Europe, consisting of the islands of Great Britain, Ireland, the Isle of Man, the Inner Hebrides, Inner and Outer Hebr ...

and

* Torres Strait land bridge, Sahul, between modern-day West Papua and Cape York * Sundaland, a 1,800,000 km² area which connected the islands of Southeast Asia at various points during the last 2.6 million years

Current land bridges

* Adam's Bridge (also known as Rama Setu), connecting

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

and

Sri Lanka Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka, also known historically as Ceylon, is an island country in South Asia. It lies in the Indian Ocean, southwest of the Bay of Bengal, separated from the Indian subcontinent, ...

*The

Isthmus of Panama The Isthmus of Panama, historically known as the Isthmus of Darien, is the narrow strip of land that lies between the Caribbean Sea and the Pacific Ocean, linking North America, North and South America. The country of Panama is located on the i ...

, whose appearance three million years ago allowed the Great American Biotic Interchange between

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

and

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

*The

Sinai Peninsula The Sinai Peninsula, or simply Sinai ( ; ; ; ), is a peninsula in Egypt, and the only part of the country located in Asia. It is between the Mediterranean Sea to the north and the Red Sea to the south, and is a land bridge between Asia and Afri ...

, linking

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

and

Eurasia Eurasia ( , ) is a continental area on Earth, comprising all of Europe and Asia. According to some geographers, Physical geography, physiographically, Eurasia is a single supercontinent. The concept of Europe and Asia as distinct continents d ...

Land bridge theory

In the late 19th and early 20th centuries, vanished land bridges were an explanation for observed affinities of plants and animals in distant locations. Such scientists as

Joseph Dalton Hooker Sir Joseph Dalton Hooker (30 June 1817 – 10 December 1911) was a British botanist and explorer in the 19th century. He was a founder of geographical botany and Charles Darwin's closest friend. For 20 years he served as director of the Ro ...

noted puzzling geological, botanical, and zoological similarities between widely separated areas, and proposed land bridges between appropriate land masses that allowed species to spread between land masses. Chapter 5: "Up-and-Down Landbridges". In geology, the concept was first proposed by Jules Marcou in ''Lettres sur les roches du Jura et leur distribution géographique dans les deux hémisphères'' ("Letters on the rocks of the Jura ountains and their geographic distribution in the two hemispheres"), 1857–1860. Hypothesized land bridges included: * ''Archatlantis'' from the West Indies to North Africa * ''Archhelenis'' from Brazil to South Africa * ''Archiboreis'' in the North Atlantic * ''Archigalenis'' from Central America through Hawaii to Northeast Asia * ''Archinotis'' from South America to Antarctica * ''

Lemuria Lemuria (), or Limuria, was a continent proposed in 1864 by zoologist Philip Sclater, theorized to have sunk beneath the Indian Ocean, later appropriated by occultists in supposed accounts of human origins. The theory was discredited with the dis ...

'' in the Indian Ocean The theory of continental drift provided an alternate explanation that did not require land bridges. However the continental drift theory was not widely accepted until the development of

in the early 1960s, which more completely explained the motion of continents over geological time.

References

External links

* {{DEFAULTSORT:Land Bridge Landforms Historical geology Biogeography Bridges