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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 Age s. Beringia was not Glaciated because Snow fall was Extremely Light due to the southwesterly winds from the Pacific Ocean having lost their moisture over the fully glaciated Alaska Range. The 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 Asia n mainland. The Bering Land Bridge is significant for several reasons, not least because it is believed to have enabled — 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 Mammal s that evolved in Asia to North America , mammals such as Lion s and Cheetah s, which Evolved into now-extinct Endemic North American species, and exporting Camelid s that evolved in North America (and later became extinct there) to Asia. 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. Beringia constantly transformed its altered Soil s and drainage patterns. Fossil remains show that Spruce , Birch and Poplar s once grew beyond their northernmost modern range today, indicating there were periods when the climate was warmer and wetter. Mastodon s, which depended on shrubs for food, were uncommon in the open dry Tundra landscape characteristic of Beringia during the colder periods; in this tundra, Mammoth s flourished instead. 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. 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 CretaceousWeil.. Fossils in is through the Bering land bridge. Had this bridge not existed at that time, the fauna of the world would be very different. 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. NOTES EXTERNAL LINKS
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