biogeography
Biogeography is the study of the distribution of species
In biology, a species is the basic unit of biological classification, classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defin ...
, a land bridge is an isthmus
An isthmus ( or ; plural: isthmuses or isthmi; from grc, ἰσθμός, isthmós, neck) is a narrow piece of land connecting two larger areas across an expanse of water by which they are otherwise separated. A tombolo is an isthmus that consist ...
or wider land connection between otherwise separate areas, over which animals
Animals (also called Metazoa) are multicellular
Multicellular organisms are organism
In biology, an organism (from Ancient Greek, Greek: ὀργανισμός, ''organismos'') is any individual contiguous system that embodies the L ...
and plant
Plants are predominantly photosynthetic
Photosynthesis is a process used by plants and other organisms to Energy transformation, convert light energy into chemical energy that, through cellular respiration, can later be released to fuel ...
s are able to cross and colonize
Colonization, or colonisation refers to large-scale population movements where the migrants maintain strong links with their or their ancestors' former country, gaining significant privileges over other inhabitants of the territory by such links ...
new lands. A land bridge can be created by marine regression
A marine regression is a geological process occurring when areas of submerged seafloor are exposed above the sea level. The opposite event, transgression (geology), marine transgression, occurs when flooding from the sea covers previously-exposed l ...
, in which sea level
Mean sea level (MSL) (often shortened to sea level) is an average
In colloquial, ordinary language, an average is a single number taken as representative of a list of numbers, usually the sum of the numbers divided by how many numbers are in th ...
s fall, exposing shallow, previously submerged sections of continental shelf
A continental shelf is a portion of a continent
A continent is one of several large landmasses. Generally identified by convention (norm), convention rather than any strict criteria, up to seven regions are commonly regarded as continen ...
; or when new land is created by plate tectonics
upright=1.35, Diagram of the internal layering of Earth showing the lithosphere above the asthenosphere (not to scale)
Plate tectonics (from the la, label=Late Latin
Late Latin ( la, Latinitas serior) is the scholarly name for the written L ...
; or occasionally when the sea floor rises due to post-glacial rebound after an ice age
An ice age is a long period of reduction in the temperature of Earth
Earth is the third planet from the Sun and the only astronomical object known to harbour and support life. 29.2% of Earth's surface is land consisting of continents and ...
.
Prominent examples
*Adam's Bridge
Adam's Bridge, '; ta, ஆதாம் பாலம் ' also known as Rama's Bridge or Rama Setu, '; ta, ராமர் பாலம் '; sa, रामसेतु ' is a chain of natural limestone
Limestone is a common type of c ...
(also known as Rama Setu), connecting India
India, officially the Republic of India (Hindi: ), 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 and dependencies by population, second-most populous ...
and Sri Lanka
Sri Lanka (, ; si, ශ්රී ලංකාව, Śrī Laṅkā, translit-std=ISO (); ta, இலங்கை, Ilaṅkai, translit-std=ISO ()), formerly known as Ceylon, and officially the Democratic Socialist Republic of Sri Lanka, is ...
* The Bering Land Bridge
Beringia is defined today as the land and maritime area bounded on the west by the Lena River
The Lena (russian: link=no, Ле́на, ; evn, Елюенэ, ''Eljune''; sah, Өлүөнэ, ''Ölüöne''; bua, Зүлхэ, ''Zülkhe''; mn, З ...
(aka Beringia), which intermittently connected Alaska
Alaska (; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Central Alaskan Yup'ik language, Yup'ik: ''Alaskaq''; tli, Anáaski) is a U.S. state in the Western United States, on the northwest extremity of the country's West Coast of the United State ...
(Northern America
Northern America is the north
North is one of the four compass points or cardinal directions. It is the opposite of south and is perpendicular to East and West. ''North'' is a noun, adjective, or adverb indicating Direction (geometry), d ...
) with Siberia
Siberia (; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive geographical region spanning much of Northern Asia. Siberia has been Russian conquest of Siberia, part of modern Russia since the latter half of th ...
(North Asia
North Asia or Northern Asia, also referred to as Siberia, is the northern region of Asia, which is defined in Geography, geographical terms and is coextensive with the Asian part of Russia, and consists of three Russian regions east of the Ural ...
) as sea levels rose and fell under the effect of ice ages
* Doggerland
Doggerland (also called Dogger Littoral) was an area of land, now submerged beneath the southern North Sea
The North Sea is a sea of the Atlantic Ocean located between Great Britain (England and Scotland), Denmark, Norway, Germany, the Nethe ...
, a former landmass in the southern North Sea
The North Sea is a sea
The sea, connected as the world ocean or simply the ocean
The ocean (also the sea or the world ocean) is the body of salt water which covers approximately 71% of the surface of the Earth.
which connected the island of Great Britain
Great Britain is an island in the North Atlantic Ocean off the northwest coast of continental Europe. With an area of , it is the largest of the British Isles, the List of European islands by area, largest European island, and the List of i ...
to continental Europe
Continental Europe or mainland Europe is the contiguous continent
A continent is any of several large landmasses. Generally identified by convention (norm), convention rather than any strict criteria, up to seven geographical region ...
during the last ice age
* The Isthmus of Panama
The Isthmus of Panama ( es, Istmo de Panamá), also historically known as the Isthmus of Darien (), is the narrow strip of land that lies between the Caribbean Sea
The Caribbean Sea ( es, Mar Caribe; french: Mer des Caraïbes; ht, Lamè Kara ...
, whose appearance three million years ago allowed the Great American Interchange
The Great American Biotic Interchange (commonly abbreviated as GABI), also known as the Great American Interchange or Great American Faunal Interchange, was an important late Cenozoic
The Cenozoic ( ; ) is Earth's current geological era
An era ...
between North America
North America is a continent
A continent is any of several large landmasses. Generally identified by convention (norm), convention rather than any strict criteria, up to seven geographical regions are commonly regarded as continen ...
and South America
South America is a continent
A continent is any of several large landmasses. Generally identified by convention (norm), convention rather than any strict criteria, up to seven geographical regions are commonly regarded as continent ...
* The Sinai Peninsula
The Sinai Peninsula, or simply Sinai (now usually ) (, ), 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 As ...
, linking Africa
Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area and 20% of i ...
and Eurasia
Eurasia () is the largest continent
A continent is any of several large landmasses. Generally identified by convention (norm), convention rather than any strict criteria, up to seven geographical regions are commonly regarded as cont ...
* The Thule Land Bridge, a since disappeared land bridge between the British Isles
The British Isles are a in the North off the north-western coast of , consisting of the islands of , , the , the and over six thousand smaller islands."British Isles", ' They have a total area of and a combined population of almost 72&nb ...
and Greenland
Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an autonomous territory
An autonomous administrative division (also referred to as an autonomous area, entity, unit, region, subdivision, or territory) is a subnational administra ...
* The De Geer Land Bridge
Land bridge theory
In the 19th century a number of scientists noted puzzling geological and zoological similarities between widely separated areas. To solve these problems, "whenever geologists and paleontologists were at a loss to explain the obvious transoceanic similarities of life that they deduced from the fossil records, they sharpened their pencils and sketched land bridges between appropriate continents." Chapter 5: "Up-and-Down Landbridges". The concept was first proposed byJules Marcou
Jules Marcou (April 20, 1824 – April 17, 1898) was a French-Swiss-American geologist.
Biography
He was born at Salins, in the ''département
In the administrative divisions of France, the department (french: département, ) is one of the t ...
in ''Lettres sur les roches du Jura et leur distribution géographique dans les deux hémisphères'' ("Letters on the rocks of the .html"_;"title="ountains
