Polar Bear Dna Shows Animals Evolved Quickly

[Rødvig]

Polar bear link

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Mikkel

[ashcraft]

Polar bear link

They find a polar bear fossil and they spend half the article trying to link it to global warming? Scientific reporting at its finest.

Brent Ashcraft

[grampa dino]

Will the polar bear become extinct or just get it on with the brown bear

and live happily ever after as a Polar-grizzly

[Nicholas]

Will the polar bear become extinct or just get it on with the brown bear

and live happily ever after as a Polar-grizzly

Pizzly! As Nat Geo called it: The ultimate of all bears but unfortunately can only live as a polar or grizzly.

[Rødvig]

You are completely wrong grampa dino, all the polar bears will move to Germany and be renamed Knut. After which they will live happily until their final days on a strict diet consisting of carefully selected junk food and tourists who jump over the fence.

Lekkim

[ashcraft]

You are completely wrong grampa dino, all the polar bears will move to Germany and be renamed Knut. After which they will live happily until their final days on a strict diet consisting of carefully selected junk food and tourists who jump over the fence.

Lekkim

Not to be contrary, but I have to wonder if polar bears and brown bears were extinct, would they be classified as separate species based on fossil remains? I would pose not. Are they truly different species then? Do they vigorously interbreed where ranges overlap, making them color phases? Mighty heavy thinkin' for a Friday. That might be a good open-ended test question for Bio II though.....

Brent Ashcraft

[Frank Menser]

Not to be contrary, but I have to wonder if polar bears and brown bears were extinct, would they be classified as separate species based on fossil remains? I would pose not. Are they truly different species then? Do they vigorously interbreed where ranges overlap, making them color phases? Mighty heavy thinkin' for a Friday. That might be a good open-ended test question for Bio II though.....

Brent Ashcraft

My guesss would be if they can be differenciated by their bone structure then fossil differences would be there (Barring DNA or even preseved hair). If they can't ask one of them if they are related to Smokey the Bear. The answer you would get-if any-would be about as reliable.

[JohnJ]

Not to be contrary, but I have to wonder if polar bears and brown bears were extinct, would they be classified as separate species based on fossil remains? I would pose not. Are they truly different species then? Do they vigorously interbreed where ranges overlap, making them color phases? Mighty heavy thinkin' for a Friday. That might be a good open-ended test question for Bio II though.....

Brent Ashcraft

Every good teacher is a little "contrary".

Based on a recent program I saw (I know it's a thin branch), the DNA and skeletal measurements are different for both species.

[tracer]

if you called them "sharks" they'd be three different species, a coupla more subspecies, and a half-dozen new names for people's mamas.

[ashcraft]

if you called them "sharks" they'd be three different species, a coupla more subspecies, and a half-dozen new names for people's mamas.

Now that's funny.

Brent Ashcraft

[siteseer]

Not to be contrary, but I have to wonder if polar bears and brown bears were extinct, would they be classified as separate species based on fossil remains? I would pose not. Are they truly different species then? Do they vigorously interbreed where ranges overlap, making them color phases? Mighty heavy thinkin' for a Friday. That might be a good open-ended test question for Bio II though.....

Brent Ashcraft

Polar bear molars are different from brown bear molars. They are shaped more for shearing meat while those of the brown bear remain more multi-purpose (crushing nuts and fruits). The muzzle is more pointed as well. Polar bears have bigger feet and their foot pads, which wouldn't fossilize, are adapted for increased traction on ice.

They do interbreed. The female offspring are fertile but the males may not be, so they may be less closely-related than a dog and a wolf.

[MarkGelbart]

Polar bears can be distinguished anatomically from grizzlies. In addition to the traits siteseer mentioned they have longer necks.

Dogs are distinguished from wolves merely on the basis of behavior. Many of the physical differences between wolves and dogs, such as floppy ears and multi-colored coats, wouldn't even show up in the fossil record.

It was interesting the scientists in the article had to remark that just because polar bears survived global warming in the past that it doesn't mean they could do so today. I think they would. Polar bears survived the Sangamonian interglacial when the north polar ice cap completely melted. I doubt their behavior has changed that much.

BTW, my book is finished and available.

http://stores.lulu.com/GeorgiaBeforePeople

[Auspex]

...BTW, my book is finished and available.

http://stores.lulu.com/GeorgiaBeforePeople

Congratulations, Mark!

[MarkGelbart]

Thanks.

I enjoyed writing it so much that I've decided to produce a second edition in ten years.

Hopefully, there will be a lot more fossil sites discovered in state within the next decade. I plan to prospect for fossils myself as well.

[Boesse]

Polar bears can be distinguished anatomically from grizzlies. In addition to the traits siteseer mentioned they have longer necks.

Dogs are distinguished from wolves merely on the basis of behavior. Many of the physical differences between wolves and dogs, such as floppy ears and multi-colored coats, wouldn't even show up in the fossil record.

Thought I'd mention - most domestic dogs have larger foreheads than wild canids, and have a frontal 'dome' - additionally, many (but definitely not all) domesticated breeds have chins that stick out further than the rostrum (i.e. underbite, most obvious in little dogs, and bulldogs/bull terriers, boxers, etc. (don't know about mastiffs). So... (most of) their skulls are readily distinguished. Bobby

[tracer]

there are several differences between the skulls of wolves and the skulls of dogs. so fossils of canids could be differentiated

[ashcraft]

They do interbreed. The female offspring are fertile but the males may not be, so they may be less closely-related than a dog and a wolf.

That may or may not be a function of relatedness, usually that is a function of transposing of chromosomes. Female mules actually are fertile once in awhile (has to do with dipoidy/triploidy as I recall), and their parents are not closely related. Humans and gorillas are much closer, but unlikely to have offspring because their chromosomal makeup (sequence of genes on respective chromosomes in this case) has changed so significantly from the common ancestor.

Brent Ashcraft

[ashcraft]

It was interesting the scientists in the article had to remark that just because polar bears survived global warming in the past that it doesn't mean they could do so today. I think they would. Polar bears survived the Sangamonian interglacial when the north polar ice cap completely melted. I doubt their behavior has changed that much.

How do we know that? Are there fossils dating from this period? They evolved once from the grizzly stock, they easily could have evolved again as the sea ice rebuilt. Same traits would have been selected for, clear fur, black skin, shredding teeth. Something to ponder.

Brent Ashcraft

[siteseer]

It seems to me that with so many anatomical differences, especially the lengthening of the neck and the changes in the teeth, it would take longer than 150,000 years to fully adapt to a different environment and one as extreme as the Arctic Circle. Polar bears are so well adapted physiologically to the cold that they are actually in more danger of overheating during strenuous physical activity than freezing.

I think more fossils should have been collected and studied before doing a study like this. It doesn't make much sense to intentionally damage even one specimen when the results could be interpreted as preliminary - based on such a small sample.

[eddie]

They find a polar bear fossil and they spend half the article trying to link it to global warming? Scientific reporting at its finest.

Brent Ashcraft

Brent,

it seems like "agenda based" science is becoming more the norm these days. While this has nothing to do with bears,

check out this "scientific" report released by the USGS on Burmese pythons in the United States:

My link

The veracity of this "research" is, at best, questionable (and refutable by any 16 year old hobbyist who knows anything

about Burmese pythons), but the fact that the authors included a range map based on a global warming prediction 100

years into the future is laughable.

Hey, maybe at some point we'll see a report about how Burmese pythons will move far enough north and grow to exaggerated lengths

such that they will be a predation threat to polar bear cubs!

Thanks,

Ed

[Rødvig]

He

y, maybe at some point we'll see a report about how Burmese pythons will move far enough north and grow to exaggerated lengths

such that they will be a predation threat to polar bear cubs!

:lolu: :lolu:

[jasonsannar]

More scientific proof of how fast evolution can occur. Nice post!