speciation

Bears: Just when we thought we had their species all figured out …

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Thumbnail for version as of 15:26, 12 December 2007
polar/brown bear hybrid

.. and could occupy our time persecuting dissenters, we learn from CBC News (July 7, 2011),

A female grizzly bear who lived in Ireland less than 50,000 years ago was an ancestor of all modern polar bears, suggesting “grolar” hybrids were an important part of polar bear history.The unexpected DNA evidence suggests that interbreeding between polar bears and brown bears — usually known as grizzly bears in North America — is not unusual at times when climate change caused the range of the two species to overlap, such as around the beginning of the last ice age.

– “Polar bears had Irish grizzly ancestor”

Yes, the grolar bear (grizzly +polar) is real, including second generation hybrids.

What was interesting was that the sequences from our brown bears were closer to modern polar bears than those ancient polar bears were,” he said in a phone interview Thursday.

In fact, the results, which Bradley said were unexpected, suggest that all polar bears share a female Irish brown bear ancestor from within the last 50,000 to 20,000 years — not that long ago on the evolutionary time-scale.

If so, that cow bear could sure swim. And brown bears do the same thing.

Is speciation all it’s cracked up to be? Wasn’t it predicted that they’d all be more separate than this?

2 Replies to “Bears: Just when we thought we had their species all figured out …

  1. 1
    Grunty says:

    “If so, that cow bear could sure swim.”

    She wouldn’t have had to. At the peak of the last Ice Age – the Last Glacial Maximum – there was an enormous ice cap covering a large chunk of the North Hemisphere and connecting North America with Europe (including what is now Ireland).

    The peak of the last Ice Age was only around 20,000 years ago. It was building up for tens of thousands of years, at least, before that. So the cow bear, and her descendants, could have walked.

  2. 2
    Barb says:

    And yet, despite the differences between brown, polar, and grizzly bears, they are all of the same ‘kind’ (to use a biblical term). There are obvious variations within a species (dogs, cats, bears) but they all reproduce with the same result. They’re not evolving into anything else.

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