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Evo­lu­tion


A Col­lec­tion of News by Moos


201023Apr18:23

Polar bear evolved rapidly

Infor­ma­tion
pub­lished 23 April 2010 | mod­i­fied 29 Decem­ber 2011
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It is a well-​known fact that the brown bear and the polar bear are closely related. Repro­duc­tion in cap­tiv­ity has been recorded. And from analy­ses of mito­chon­dr­ial DNA it is undis­puted that polar bears con­sti­tute a lin­eage within the genetic diver­sity of brown bears. But, due to an extremely poor fos­sil record not much was known about the polar bear’s evo­lu­tion and the moment of their diver­gence. In a recent pub­li­ca­tion in Pro­ceed­ings of the National Acad­emy of Sci­ences, researchers show that the polar bear branched off the brown bear lin­eage prob­a­bly just 150,000 years ago.

Using advanced DNA tech­nol­ogy they were able to com­pare DNA from a fos­sil polar bear jaw, exca­vated in Spits­ber­gen, with DNA from bears liv­ing at present times. Fur­ther­more, using mol­e­c­u­lar dat­ing and sta­ble iso­tope analy­ses, they show that this “young” polar bear early in its evo­lu­tion­ary his­tory, already was an inhab­i­tant of the Artic sea ice and has adapted very rapidly to its cur­rent and unique ecol­ogy at the top of the Arc­tic marine food chain. All in all the polar bear pro­vides an excel­lent exam­ple of evo­lu­tion­ary oppor­tunism within a wide­spread mam­malian lineage.

(Source: PNAS (Early Edi­tion), 01.03.2010)

Goal: 7000 tigers in the wild

Tiger range countries map

Tiger map” (CC BY 2.5) by Sander­son et al., 2006.

about zoos and their mis­sion regard­ing breed­ing endan­gered species, nature con­ser­va­tion, bio­di­ver­sity and edu­ca­tion, which of course relates to the evo­lu­tion of species.
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