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Encyclopedia > Bering land bridge
Nautical chart of Bering Strait, site of former land bridge between Asia and North America
Nautical chart of Bering Strait, site of former land bridge between Asia and North America

The Bering land bridge, also known as Beringia, was a land bridge roughly 1,000 miles (1,600 km) north to south at its greatest extent, which joined present-day Alaska and eastern Siberia at various times during the Pleistocene ice ages. Beringia was not glaciated because snowfall was extremely light due to the southwesterly winds from the Pacific Ocean having lost their moisture over the fully glaciated Alaska Range. Image File history File links This image was produced from ENC S-57 data supplied by the US NOAA Office of Coast Survey, chart US1BS03M, and is free from copyright. ... Image File history File links This image was produced from ENC S-57 data supplied by the US NOAA Office of Coast Survey, chart US1BS03M, and is free from copyright. ... Portion of chart of Bering Strait, site of former land bridge between Asia and North America. ... Satellite photo of the Bering Strait Photo across the Bering Strait Nautical chart of the Bering Strait The Bering Strait (Russian: ) is a sea strait between Cape Dezhnev, Russia, the easternmost point (169°43 W) of the Asian continent and Cape Prince of Wales, Alaska, the westernmost point (168°05... For other uses, see Asia (disambiguation). ... North America North America is a continent[1] in the Earths northern hemisphere and (chiefly) western hemisphere. ... This article or section does not cite its references or sources. ... To help compare different orders of magnitude this page lists lengths between 106 and 107 m (1,000 and 10,000 km). ... Official language(s) None[1] Spoken language(s) English 85. ... “Siberian” redirects here. ... The Pleistocene epoch (IPA: ) on the geologic timescale is the period from 1,808,000 to 11,550 years BP. The Pleistocene epoch had been intended to cover the worlds recent period of repeated glaciations. ... Variations in CO2, temperature and dust from the Vostok ice core over the last 400 000 years For the animated movie, see Ice Age (movie). ... This article is about the geological formation. ... Snow is a type of precipitation in the form of crystalline water ice, consisting of a multitude of snowflakes that fall from clouds. ... For the television series see Rain Shadow. ...


The Bering Strait, the Chukchi Sea to the north and the Bering Sea to the south, are all shallow seas (map, right). During cycles of global cooling, such as the most recent ice age, enough sea water became concentrated in the ice caps of the Arctic and Antarctic that the subsequent drop in eustatic sea levels exposed shallow sea floors. Other land bridges around the world have been created and re-flooded in the same way: approximately 14,000 years ago, mainland Australia was linked both to New Guinea and to Tasmania, the British Isles were an extension of continental Europe via the English Channel, and the dry basin of the South China Sea linked Sumatra, Java and Borneo to the Asian mainland. Satellite photo of the Bering Strait Photo across the Bering Strait Nautical chart of the Bering Strait The Bering Strait (Russian: ) is a sea strait between Cape Dezhnev, Russia, the easternmost point (169°43 W) of the Asian continent and Cape Prince of Wales, Alaska, the westernmost point (168°05... Chukchi Sea (Russian: Чуко́тское мо́ре) is a marginal sea of the Arctic Ocean, between Chukotka and Alaska. ... Satellite photo of the Bering Sea Bering Sea and the North Pacific Ocean Bearing Sea with Kamchatka Peninsula and Alaska The Bering (or Imarpik) Sea is a body of water north of, and separated from, the north Pacific Ocean by the Alaska Peninsula and Aleutian Islands. ... Variations in CO2, temperature and dust from the Vostok ice core over the last 400 000 years For the animated movie, see Ice Age (movie). ... The red line indicates the 10°C isotherm in July, commonly used to define the Arctic region border Satellite image of the Arctic surface The Arctic is the region around the Earths North Pole, opposite the Antarctic region around the South Pole. ... Greek ἀνταρκτικός, opposite the arctic) is a continent surrounding the Earths South Pole. ... It has been suggested that this article or section be merged with sea level. ... For considerations of sea level change, in particular rise associated with possible global warming, see sea level rise. ... Slogan or Nickname: The Apple Isle; Holiday Isle Motto(s): Ubertas et Fidelitas (Fertility and Faithfulness) Other Australian states and territories Capital Hobart Government Constitutional monarchy Governor William Cox Premier Paul Lennon (ALP) Federal representation  - House seats 5  - Senate seats 12 Gross State Product (2004-05)  - Product ($m)  $16,114... This article describes the archipelago in north-Western Europe. ... For other uses, see Europe (disambiguation). ... Satellite view of the English Channel The English Channel (French: , the sleeve) is an arm of the Atlantic Ocean that separates the island of Great Britain from northern France and joins the North Sea to the Atlantic. ... Filipino name Tagalog: Luzon Sea Portuguese name Portuguese: Mar da China Meridional Vietnamese name Vietnamese: The South China Sea is a marginal sea south of China. ... Sumatra (also spelled Sumatera) is the sixth largest island in the world (approximately 470,000 km²) and is the largest island entirely in Indonesia (two larger islands, Borneo and New Guinea, are partially in Indonesia). ... Java (Indonesian, Javanese, and Sundanese: Jawa) is an island of Indonesia, and the site of its capital city, Jakarta. ... It has been suggested that this article or section be merged with Kalimantan. ... For other uses, see Asia (disambiguation). ...

Evolution of the Bering land bridge

The Bering Land Bridge is significant for several reasons, not least because it is believed to have enabled human migration to the Americas from Asia about 25,000 years ago[1] (see Models of migration to the New World). Recent studies[2] have indicated that of the people migrating across this land bridge during that time period, only 70 left their genetic print in modern descendants, a minute effective founder population— easily misread as though implying that only 70 people crossed to North America. Sea-going coastal settlers may also have crossed much earlier, but scientific opinion remains divided on this point, and the coastal sites that would offer further information now lie submerged in up to a hundred metres of water offshore. Land animals were able to migrate through Beringia as well, bringing mammals that evolved in Asia to North America, mammals such as lions and cheetahs, which evolved into now-extinct endemic North American species, and exporting camelids that evolved in North America (and later became extinct there) to Asia. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Net migration rates for 2006: positive (blue), negative (orange) and stable (green). ... There are several popular models of migration to the New World proposed by the anthropological community. ... When a species invades a new area, especially an island, the original, small population is called a founder population. ... Subclasses & Infraclasses Subclass †Allotheria* Subclass Prototheria Subclass Theria Infraclass †Trituberculata Infraclass Metatheria Infraclass Eutheria Mammals (class Mammalia) are warm-blooded, vertebrate animals characterized by the presence of sweat glands, including those that produce milk, and by the presence of: hair, three middle ear bones used in hearing, and a neocortex... North America North America is a continent[1] in the Earths northern hemisphere and (chiefly) western hemisphere. ... For other uses, see Lion (disambiguation). ... This article is about the animal. ... This article is about evolution in biology. ... In biology and ecology endemic means exclusively native to a place or biota, in contrast to cosmopolitan or introduced. ... Species  Lama glama  Lama guanicoe  Vicugna pacos  Vicugna vicugna  Camelus dromedarius  Camelus bactrianus The four llamas and two camels are camelids: members of the biological family Camelidae, the only family in the suborder Tylopoda. ...


The rise and fall of global sea levels has exposed and submerged the land bridge in several periods of the Pleistocene. The bridging land mass called "Beringia" is believed to have existed both in the glaciation that occurred before 35,000 BC and during the more recent period 22,000-7,000 years ago. By c. 4000 BC the coastlines had assumed approximately their present configurations. The Pleistocene epoch (IPA: ) on the geologic timescale is the period from 1,808,000 to 11,550 years BP. The Pleistocene epoch had been intended to cover the worlds recent period of repeated glaciations. ... A glaciation (a created composite term meaning Glacial Period, referring to the Period or Era of, as well as the process of High Glacial Activity), often called an ice age, is a geological phenomenon in which massive ice sheets form in the Arctic and Antarctic and advance toward the equator. ...


Beringia constantly transformed its ecology as the changing climate affected the environment, determining which plants and animals were able to survive. The land mass could be a barrier as well as a bridge: during colder periods, glaciers advanced and precipitation levels dropped. During warmer intervals clouds, rain and snow altered soils and drainage patterns. Fossil remains show that spruce, birch and poplars once grew beyond their northernmost modern range today, indicating there were periods when the climate was warmer and wetter. Mastodons, which depended on shrubs for food, were uncommon in the open dry tundra landscape characteristic of Beringia during the colder periods; in this tundra, mammoths flourished instead. This article does not cite any references or sources. ... Snow is a type of precipitation in the form of crystalline water ice, consisting of a multitude of snowflakes that fall from clouds. ... Loess field in Germany Surface-water-gley developed in glacial till, Northern Ireland Technically, soil forms the pedosphere: the interface between the lithosphere (rocky part of the planet) and the biosphere, atmosphere, and hydrosphere. ... For other uses, see Fossil (disambiguation). ... Species About 35; see text. ... Species Many species; see text and classification Birch is the name of any tree of the genus Betula, in the family Betulaceae, closely related to the beech/oak family, Fagaceae. ... This article is about woody plants of the genus Populus. ... Mastodons or Mastodonts (meaning nipple-teeth) are members of the extinct genus Mammut of the order Proboscidea and form the family Mammutidae; they resembled, but were distinct from, the woolly mammoth which belongs to the family Elephantidae. ... For other uses, see Tundra (disambiguation). ... This article is about the genus Mammuthus. ...

Contents

Previous connections

Biogeographical evidence demonstrates previous connections between North America and Asia. Similar dinosaur fossils have been found between Asia and North America. For instance the dinosaur Saurolophus was found in both Mongolia and western North America. Relatives of Troodon, Triceratops, and even Tyrannosaurus rex all came from Asia. Biogeography is the science which deals with patterns of species distribution and the processes that result in such patterns. ... Orders & Suborders Saurischia Sauropodomorpha Theropoda Ornithischia Thyreophora Ornithopoda Marginocephalia Dinosaurs were vertebrate animals that dominated the terrestrial ecosystem for over 160 million years, first appearing approximately 230 million years ago. ... For other uses, see Asia (disambiguation). ... North America North America is a continent[1] in the Earths northern hemisphere and (chiefly) western hemisphere. ... Binomial name Saurolophus osborni Brown, 1912 Species S osborni S. angustirostris Rozhdestvensky, 1952 Saurolophus is a large hadrosaurid. ... Binomial name Troodon formosus Leidy, 1856 Troodon formosus was a relatively small, bird-like dinosaur from the late Cretaceous Period (68–65 MYA). ... Species (type) Marsh, 1890 Triceratops (IPA: ) was a herbivorous genus of ceratopsid dinosaur that lived during the late Maastrichtian stage of the Late Cretaceous Period, around 68 to 65 million years ago (mya) in what is now North America. ... Binomial name Tyrannosaurus rex Osborn, 1905 Synonyms Manospondylus gigas Dynamosaurus imperiosus Dinotyrannus megagracilis Nanotyrannus lancensis? Tyrannosaurus (IPA pronunciation or ; from the Greek τυραννόσαυρος, meaning tyrant lizard) is a genus of tyrannosaurid theropod dinosaur. ...


However, while there is considerable evidence for faunal interchange of dinosaurs in the Campanian and Maastrichtian phases of the Late Cretaceous, mammals seem not to have dispersed so easily, perhaps because of their relatively small size; at any rate, there is no direct evidence supporting mammalian faunal exchange in the Cretaceous[3]. Fossils in China demonstrate a migration of Asian mammals into North America around 55 million years ago. By 20 million years ago, evidence in North America shows a further interchange of mammalian species. Some, like the ancient saber-toothed cats, have a recurring geographical range: Europe, Africa, Asia, and North America. The only way they could reach the New World is through the Bering land bridge. Had this bridge not existed at that time, the fauna of the world would be very different. The fossilized skeleton of a sabre-toothed cat The terms saber-toothed cat and saber-toothed tiger describes numerous cat-like species that lived during various parts of the Cenozoic and evolved their saber-toothed characteristics entirely independently. ... Frontispiece of Peter Martyr dAnghieras De orbe novo (On the New World). Carte dAmérique, Guillaume Delisle, 1722. ...


Most recently, molecular phylogenetics is now being used to trace the history of faunal exchange and diversification, through the genetic history of parasites and pathogens of North American ungulates. An international Beringian Coevolution Project is collaborating to provide material to assess the pattern and timing of faunal exchange and the potential impact of past climatic events on differentiation. Phylogenetic groups, or taxa, can be monophyletic, paraphyletic, or polyphyletic. ... Ungulates (meaning roughly hoofed or hoofed animal) make up several orders of mammals, of which six survive: Artiodactyla: even-toed ungulates, cattle, sheep, goats, pigs, antelope, and many others Cetacea: whales and dolphins (which evolved from hoofed land animals) Perissodactyla: odd-toed ungulates such as horses and rhinos Proboscidea: elephants...


Notes

  1. ^ National Genographic. "Atlas of the Human Journey." 2005. May 2, 2007. [1]
  2. ^ J. Hey, 2005. "On the Number of New World Founders: A Population Genetic Portrait of the Peopling of the Americas" in PLoS Biol 2005 May 24;3(6):e193
  3. ^ Weil.

External links

References

  • Pielou, E. C., After the Ice Age : The Return of Life to Glaciated North America 1992
  • Hey, Jody, 2005. "On the Number of New World Founders: A Population Genetic Portrait of the Peopling of the Americas" in PLoS Biol 2005 May 24;3(6):e193 [2]

See also


  Results from FactBites:
 
Land bridge - Wikipedia, the free encyclopedia (513 words)
The best-known is the Bering land bridge, which connected North Asia and Alaska during the last ice age, enabling humans to migrate from Eurasia to the Americas by walking.
Land bridges generally occur on continental shelves: the Bering Strait, where the Bering Land Bridge was during the last glaciation, is part of the edge of the North American plate.
A land bridge that rose from the sea floor because of upthrust at the edge of a continental plate is Central America.
Bering land bridge - Wikipedia, the free encyclopedia (531 words)
The Bering land bridge, also known as Beringia, was a land bridge roughly 1600 km (1000 miles) north to south at its greatest extent, which joined present-day Alaska and eastern Siberia at various times during the ice ages.
The Bering Strait, the Chukchi Sea to the north and the Bering Sea to the south, are all shallow seas.
Land animals were able to migrate through Beringia as well, bringing mammals that evolved in Asia to North America, mammals such as lions and cheetahs, which evolved into now-extinct endemic North American species, and exporting camelids that evolved in North America (and later became extinct there) to Asia.
  More results at FactBites »

 
 

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