DocM Posted July 8, 2011 Share Posted July 8, 2011 ....Britain & Ireland.... Link.... An international team of scientists has discovered that the female ancestor of all living polar bears was a brown bear that lived in the vicinity of present-day Britain and Ireland just prior to the peak of the last ice age -- 20,000 to 50,000 years ago. Beth Shapiro, the Shaffer Associate Professor of Biology at Penn State University and one of the team's leaders, explained that climate changes affecting the North Atlantic ice sheet probably gave rise to periodic overlaps in bear habitats. These overlaps then led to hybridization, or interbreeding -- an event that caused maternal DNA from brown bears to be introduced into polar bears. The research, which is led by Shapiro and Daniel Bradley of Trinity College Dublin, is expected to help guide future conservation efforts for polar bears, which are listed as threatened under the Endangered Species Act. The results of the study will be published on 7 July 2011 in the journal Current Biology. Polar and brown bears are vastly different species in terms of body size, skin and coat color, fur type, tooth structure, and many other physical features. Behaviorally, they are also quite distinct: Polar bears are expert swimmers that have adapted to a highly specialized, arctic lifestyle, while brown bears -- a species that includes Grizzlies and Kodiaks -- are climbers that prefer the mountain forests, wilderness regions, and river valleys of Europe, Asia, and North America. "Despite these differences, we know that the two species have interbred opportunistically and probably on many occasions during the last 100,000 years," Shapiro said. "Most importantly, previous research has indicated that the brown bear contributed genetic material to the polar bear's mitochondrial lineage -- the maternal part of the genome, or the DNA that is passed exclusively from mothers to offspring. But, until now, it was unclear just when modern polar bears acquired their mitochondrial genome in its present form." > Link to comment Share on other sites More sharing options...
Allan Posted July 8, 2011 Share Posted July 8, 2011 That is one of the cutest pics I've seen. The baby sleeping is adorable... able to kill me, but, still adorable. Momma she's saying "step one more step, and I kill you." Now, for the story - as Spock would say - Fascinating. Link to comment Share on other sites More sharing options...
neoadorable Posted July 8, 2011 Share Posted July 8, 2011 the originated on The Island? Link to comment Share on other sites More sharing options...
Unix2 Posted July 8, 2011 Share Posted July 8, 2011 Yes, that pic with that baby looks so cute. The mother you can tell that she looks evil... :laugh: Link to comment Share on other sites More sharing options...
neoadorable Posted July 9, 2011 Share Posted July 9, 2011 she's not evil, she's just guarding her cub from the photo-happy humans Link to comment Share on other sites More sharing options...
Tom Posted July 9, 2011 Share Posted July 9, 2011 I heard they originated in around Serbia and due to the ice-age that plagued most of Europe brown-bear grizzly's / or something very close to that got caught trapped by it whilst the rest of the brown bears migrated south. Because of that they were forced to evolve. I also know that polar bears aren't white... they have black skin with transparent fur. O_O It's also the only bear that doesn't hibernate. Link to comment Share on other sites More sharing options...
KingCrimson Posted July 9, 2011 Share Posted July 9, 2011 It's just a white grizzly bear. Link to comment Share on other sites More sharing options...
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