Intelligent Design

Polar bears and mammalian speciation

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The polar bear (Ursus maritimus) exhibits numerous adaptations to cold environments, fur, foot pads, head shape, exclusively carnivorous diet, heightened sense of smell, etc. Their close relationship to the brown bear (Ursus arctos) has long been recognised. Fertile hybrids are well-documented in captivity and there are rare examples of hybrids in the wild – the most recent being in 2006. Interbreeding, however, has not outweighed other taxonomic criteria, although it has been a factor in moving the polar bear from the genus Thalarctos back to the genus Ursus. “With their distinctly different morphology, metabolism, and social and feeding behaviors, the polar and brown bears are classified as separate species.” Interestingly, a cluster of brown bears (known as ABC bears) have been found with close genetic links to polar bears.

“Recent genetic studies have shown that polar bears evolved from within brown bears, and that a genetically unique clade of brown bear populations that live exclusively on the Admiralty, Baranof, and Chichagof (ABC) islands of southeastern Alaska’s Alexander Archipelago are more closely related to polar bears than to other brown bears.”

Speciation, then, has occurred, but when? how? and over what timescale? The opportunity to constrain the answers to these questions has come with the discovery of a jawbone with diagnostic polar bear traits from a site in Norway estimated to be 130-110 ky old. This makes it the most ancient sub-fossil yet to be recovered.
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2 Replies to “Polar bears and mammalian speciation

  1. 1
    tribune7 says:

    The money quote:

    By contrast, Darwinism explains only information-neutral (finch beaks and peppered moths) or information-degradation (antibiotic resistance) scenarios. For confusing these various types of biological transformations, Darwinism’s influence on biology has been unhealthy and scientific progress has been inhibited.

  2. 2
    Robert Byers says:

    Yes the polar bear is just another bear from the south whether a brown one or even this is not relevant.
    The change to polar type must of been instant without intermediates in any point.
    So it follows that there must be a innate mechanism that is triggered to allow even important physical changes suddenly.
    Not evolution by selection etc but another mechanism that likewise must of been operative, perhaps still thee, since the great diversity in a post flood world.

    As Mr Berlinski would ask HOW many changes and how long and how interconnected was there between a brown and a white bear.?
    How do evolutionists see this working? How was the intermediates able to thrive long enough to allow further advances but didn’t survive to this but only those who further advanced? Why?
    The answer is that there were no intermediates but instant adaptation from innate triggers.
    Just as creationists can all deny evolution by selection/mutation we can suggest there is another , unrealized, mechanism for minor instant changes.

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