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Tuesday, March 2, 2010

Ancient DNA Suggests Polar Bears Evolved Recently


"The polar bear probably evolved no more than 150,000 years ago and is most closely related to brown bears that now live in southeastern Alaska, new genetic analyses of a rare fossil suggest."
"Ursus maritimus, the polar bear, is a specialized predator that — ignoring the bears that forage for garbage in towns and villages along the Arctic coast — hunts solely on sea ice."
"Several previous studies agreed that polar bears are closely related to brown bears but provided widely divergent answers about when polar bears first evolved, with estimates ranging between 70,000 and 1 million years ago, says Charlotte Lindqvist, an evolutionary biologist at the University at Buffalo in New York. Now, genetic analyses of material from a fossil first described two years ago narrow the window when the huge white bears first appeared, Lindqvist and her colleagues report in a paper to be published in the Proceedings of the National Academy of Sciences."
"The fossil, a jawbone found on an island in Norway’s Svalbard archipelago, was unearthed from rocks laid down as sediment between 110,000 and 130,000 years ago. Certain features of the jawbone and its teeth, including their size and shape, indicate the remains come from a polar bear and not another type of bear, Lindqvist says."
"The Scandinavian remains represent by far the oldest polar bear fossil yet found, she notes."
"Using material drilled from one of the fossil’s canine teeth, researchers were able to reconstruct the bear’s mitochondrial genome, the sequence of genetic material passed down only through female ancestors. Then, the scientists compared those results with the mitochondrial genomes of six other specimens, including modern polar bears and brown bears from two regions in Alaska."
"Together, the genetic tests show that modern-day polar bears, which live throughout the Arctic and fall within one species, are most closely related to brown bears living on islands in Alaska’s panhandle — the so-called ABC islands of Admiralty, Baranof and Chichagof. The analyses also suggest that polar bears first appeared about 150,000 years ago, not too long before the Svalbard polar bear patrolled the Arctic."

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Thoughts worth thinking about

"Our subconscious minds have no sense of humor, play no jokes and cannot tell the difference between reality and an imagined thought or image. What we continually think about eventually will manifest in our lives."-Sidney Madwed



Laws alone can not secure freedom of expression; in order that every woman and man present their views without penalty, there must be spirit of tolerance in the entire population.- Albert Einstein Too often we underestimate the power of a touch, a smile, a kind word, a listening ear, an honest compliment, or the smallest act of caring, all of which have the potential to turn a life around. - Leo Buscaglia



A person's true wealth is the good he or she does in the world. - Mohammed



Our task must be to free ourselves... by widening our circle of compassion to embrace all living creatures and the whole of nature and its beauty. -Albert Einstein



The best way to find yourself, is to lose yourself in the service of others. - Ghandi



The unselfish effort to bring cheer to others will be the beginning of a happier life for ourselves. - Helen Keller



Aim for success, not perfection. Never give up your right to be wrong, because then you will lose the ability to learn new things and move forward with your life. Remember that fear always lurks behind perfectionism. Confronting your fears and allowing yourself the right to be human can, paradoxically, make yourself a happier and more productive person. - Dr. David M. Burns



Life is as dear to a mute creature as it is to man. Just as one wants happiness and fears pain, just as one wants to live and not die, so do other creatures. -His Holiness The Dalai Lama



Mankind's true moral test, its fundamental test (which lies deeply buried from view), consists of its attitude towards those who are at its mercy: animals. And in this respect mankind has suffered a fundamental debacle, a debacle so fundamental that all others stem from it. -



Milan Kundera, The Unbearable Lightness of Being



The worst sin towards our fellow creatures is not to hate them, but to be indifferent to them. That's the essence of inhumanity. -George Bernard Shaw

Ego's trick is to make us lose sight of our interdependence. That kind of ego-thought gives us a perfect justification to look out only for ourselves. But that is far from the truth. In reality we all depend on each other and we have to help each other. The husband has to help his wife, the wife has to help the husband, the mother has to help her children, and the children are supposed to help the parents too, whether they want to or not.-Gehlek Rinpoche Source: "The Best Buddhist Writing 2005 pg. 165

The hostile attitude of conquering nature ignores the basic interdependence of all things and events---that the world beyond the skin is actually an extension of our own bodies---and will end in destroying the very environment from which we emerge and upon which our whole life depends.