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Polar bears may have been around for 4-5M years

Three days ago, we discussed the claim about palm trees in the Antarctica aproximately 52-53 million years ago. There's one more paper about a similar topic that was published in recent two weeks. The New York Times wrote the following story about it:

How Brown and Polar Bears Split Up, but Continued Coupling
See other articles that mention the study's co-author Charlotte Lindqvist.

At any rate, the media reports refer to a paper in PNAS.

The paper by Webb Miller et al. (26 authors in total) is called
Polar and brown bear genomes reveal ancient admixture and demographic footprints of past climate change
They looked at DNA markers of polar bears as well as other bears. The main question is: When did polar bears separate as a new species?

As recently as a year ago, folks in that field would tell you that it was about 150,000 years ago: the polar bears were supposed to be a very modern invention, one that had to evolve very quickly. In April 2012, it was moved to 500,000 years ago. This new paper claims that the DNAs have apparently evolved independently for 4-5 million years.

This claim, if true, moves the separate life of the polar bears as a species before quaternary glaciation (also known as the Pleistocene glaciation or the current ice age) which began 2.58 million years ago and despite the screaming by the global warming fearmongers, it continues even today (by definition, that's because the Greenland has a permanent ice sheet).

I want you to appreciate the implications of this claim. The fearmongers have shamelessly tried to invent hundreds of bogus worrisome claims and identify tons of species endangered by the so-called global warming. They have failed miserably but there was still one charismatic species, the polar bears, for which it looked at least plausible that it could be endangered if there were some warming.

The world population of polar bears grew by a factor of four or five or so during the recent 50 years – from 5,000 to 20,000-25,000 – but despite this fact, you may still find it plausible to believe that they need chilly enough climate to thrive.

However, this new research seems to imply that the polar bears began to develop as a separate species in a significantly warmer world – a world in which the Greenland had no permanent ice sheets. And the same was arguably true about the Antarctica, too. Be sure that the Arctic Ocean was ice-free for a significant portion of the year. Nevertheless, the polar bears chose those warm epochs to establish themselves as a separate species.

Quite generally, I find it preposterous if someone believes that permanent ice creates the good – or even necessary – environment for any life form. Everyone whose body parts have ever frozen must understand what I am talking about. (I was once sliding on a Norwegian glacier for about 200 meters, using hands to decelerate, which was ultimately successful. I didn't feel them for 2 days.) Every organism contains water and if it freezes, life comes to a halt. Think about it.

Some species such as the polar bears may be more resilient than others so that they may tolerate more chilly conditions than what other species might withstand – and that gives them a "relative" advantage. They may even find it helpful if their prospective dinner is shaken and paralyzed by freezing conditions. But they don't really depend on it. They don't like those chilly, sub-freezing conditions in an absolute sense. No one does. There would be nothing wrong with a world that would come out of quaternary glaciation (and this is just a complete speculation because nothing indicates that we are approaching this geological event). Life on Earth – with pretty much the same composition of major species that we know today (including polar bears and some ancestors of humans) – has already tried it and the results were highly encouraging.

And that's the memo.

Bonus: Tomorrow at 7:31 a.m. Pilsner Summer Time (10:31 p.m. Sunday Californian Daylight Time), NASA will try to land the Curiosity rover on Mars. It should study "hospitability" of the Red Planet and prepare the terrain for manned missions (perhaps plant some tomatoes). The scary 7 minutes will be aired on Toshiba screens on Times Square, New York City. NASA TV will probably not show that live but there will surely be lots of related stuff over there.

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snail feedback (29) :

reader Smoking Frog said...

Lubos - For your argument to work, it must assume that the Arctic will warm up as fast as the alarmists claim it will, but in that case the 4-5 million years may be irrelevant, since the bears may have adapted to the Arctic far more recently, but would not be able to adapt to warmth occurring so soon as the alarmists expect.

Also: It is only true in a relative sense that no animal likes the cold; the animal may prefer a given cooler temperature to a given warmer temperature or higher.

I've read many times in my life that Eskimos find the warm temperatures here in the Lower 48 uncomfortable - don't know if it's true, but that's what lots of people say, and it's not supposed to be due to individual adaptation but rather that the additional fat layer is genetically determined.

reader Smoking Frog said...

Maybe I should have said "only true in an absolute sense"!

reader Gordon Wilson said...

Smoking frog: Your argument is flawed---" but rather that the additional fat layer is genetically determined."
Easy to demolish---We Canadians in the cold climate are lithe, svelte
god-like specimens, while Americans resemble Herman cartoons-- :)

reader papertiger0 said...

the zoos are full of them. No special adaptation required except a willingness to mug for the camera.

reader Susan C. said...

The important part of your post is "this claim, if true,..."

There are some serious problems with this paper, in my opinion. As an evolutionary zoologist with a interest in polar bear evolution and a background in paleoclimate, I am in the process of a review of this paper. Look for it sometime in the next few weeks at my new blog, PolarBearScience.


reader Werdna said...

"They looked at DNA markers of polar bears as well as other bears. The
main question is: When did polar bears separate as a new species?"

Actually, if you define species in the traditional way, Polar Bears would not qualify as a separate species. They may have sex with Brown Bears, make viable cubs, and those cubs may have cubs of their own. That is what traditionally defines being of the same species. They are more like a different "race" of Brown Bear than a different species.

BTW, the PNAS study makes some very unjustifiable conclusions about the effect of climate on polar bears:

Contrary to their own data!

reader Richard DeSousa said...

"Quite generally, I find it preposterous if someone believes that permanent ice creates the good – or even necessary – environment for any life form. Everyone whose body parts have ever frozen must understand what I am talking about. (I was once sliding on a Norwegian glacier for about 200 meters, using hands to decelerate, which was ultimately successful. I didn't feel them for 2 days.) Every organism contains water and if it freezes, life comes to a half. Think about it."

Dear Lubos: Did you mean "halt" rather then "half?" Sentence befor "Think about it."

reader Susan C. said...

"They are more
like a different "race" of Brown Bear than a different species."

I know a lot of people have been taught that the definition of a species an inability to hybridize and produce viable offspring with other species. But that is a simplified definition that, in practise, is simply not true.

One of the things that recent genetic studies have shown us is how many species DO hybridize in the wild, at least sometimes. Harp seals and hooded seals (in different genera), for example; fin and blue whale, amongst many others.

The point is that these occasional hybridization events really don't impact the species over the long term and do not invalidate their species status.

On that point, the World Climate Report critique made me cringe. But for the other issues, regarding the climate correlations, I think they are likely spot on.

Not a great paper overall.

reader Werdna said...

A species is a difficult thing to define in any consistent way. The traditional definition does have problems as you say, but I would be interested to know what "operational" definition is typically used now in place of the old traditional definition.

It would be helpful if people clarified what they mean by species for those of us that expect people to mean the traditional definition when they say "species". Call me old fashioned ;)

reader Dilaton said...

Huh, what's the coupling constant between brown and polar bears?
That's a silly title in the New York Times, since how are they suposed to split up if the coupling constant is zero :-P ?!

I`m sorry but reading the title made me LOL :-D

reader Ignacio Mosqueira said...

What I find preposterous is that you would find it impossible to conceive that some creatures do in fact depend on ice to survive. Such a statement is so patently foolhardy that it taints any other opinions you might offer.

Instead of spreading anti-GW propaganda you would do well to spend your time figuring out ways in which climate change might be mitigated.

reader Smoking Frog said...

Gordon Wilson - I trust that's a joke. White Canadians have not lived up there for tens of thousands of years.

reader Smoking Frog said...

Of course he meant "halt." Don't be silly.

reader brothersmartmouth said...

They thought a Quebec population was just over 600. They found just over 1000 and called the population "stable". But, the bears were looking thinner.
How you can weigh a polar bear, as well as the 50% that didn't exist previously, from a plane has yet to be explained.

reader Luboš Motl said...

Dear Ignacio, LOL. Sometimes the fearmongers' comments are so funny that I have to check whether they were written by real people. But it seems so in your case. Everyone: check for his name, you will find him in the American Geophysical Union etc.

The amusing adjective "patently foolhardy" is obviously a codeword for "blasphemous". But what's much more important than whether a statement is blasphemous in the eyes of unhinged brainwashed bigots like you is whether it is correct. And be sure that my statement is correct and accurate. Try to name a counterexample, you will fail. You will fail for a simply reason. Just look at the definition of life

You will find out that it's a group of self-sustaining processes. Pretty much all of the defining processes of life, as long as we talk about life on Earth, depend on liquid water. Take metabolism, for example:

All those processes depend on water solutions of various compounds and ions. The molecules and ions have to flow for the processes to continue so the water molecules in the environment has to be liquid. Consequently, the temperature can't be much lower than the freezing point - there's a lot of life occurring at the level of cells, after all, and cells are universal units of living matter, so it's not hard to see why my statement is completely universal - and if you think about the positive roles that ice could play, you will find out that it may at most play the role of a generic solid, like in the case of a polar bear hunting for seals. But when it's so, it's replaceable by any other solid - by beaches of oceans and rocks at the ocean-land boundaries.

A life form on Earth can't possibly depend on life in a way that couldn't be replaced by something else.

Before and instead of worshiping delusionary pseudoscientific cliches about "mitigation', you should sometimes try to use your brain but it's probably too much to ask for.

reader Luboš Motl said...

Well, organisms may also be thinner because it's healthier and they don't have to keep too huge fat reserves because they have access to regular food, so it may be a good thing, even if it is true.

reader Ignacio Mosqueira said...

I have spent no time at all studying life of any kind. My statement is based on the obvious observation that a life form's reliance on ice need not be encoded on its DNA and your comment that ice can simply be replaced by something else is beneath you. Take any the whole artic web of life from lemmings to caribou and everything else and the balance is guaranteed to be forever disrupted with species losers and others winners. In time a new quasi-equilibrium would be established but claiming that no species would suffer the consequences is absurd.

Once again spend your time figuring out how the change might be mitigated. Look into it. Co2 capture is interesting from an engineering point of view and might work. Make yourself useful instead of wasting everyone's brain cells with inanities.

reader Luboš Motl said...

Dear Ignacio, having spent no time at all studying life of any kind isn't a good starting point for meaningful arguments about life. Why are you arguing about something you know nothing about?

I didn't claim that a change of some irrelevant detail in the environment such as ice can't help some species relatively to others. What I have claimed - and proved - is that the ice loss doesn't present a danger for anyone in the absolute sense. I've been very careful about my formulations so that they are accurate and unassailable so it may be a good idea for you to study what I have written if you haven't spent any time at all studying life.

Lemmings are herbivorous

eating leaves, grass etc. So they need things that just don't grow out of frozen ice. Lemmings are close to me - the Czech translation "lumík" is one of the variations of my nickname "lumo". ;-) Caribous are more complicated - ruminants - but it's still true, much like for polar bears or lemmings, that ice isn't good for them in an absolute sense. At most, they're more tolerant towards such chilly environment.

CO2 capture isn't interesting from engineering viewpoint. It's a stupid, shallow, and useless would-be challenge promoted by dimwits. There are millions of things that are more interesting and potentially more useful challenges than CO2 capture.

reader brothersmartmouth said...

Can you give me one example of an arctic animal that does this.

reader Luboš Motl said...

As proven by your very own comment, polar bears do. There's clearly no overall shortage of food in that example because the total number of polar bears went up. On the other hand, the animals got less fat while they still survived which proves that they can afford to get thinner.

reader brothersmartmouth said...

Thank you for the reply. The article you posted said,"
Based on the assumption that extra weight makes birds more vulnerable to diurnal predators". This makes sense. But those same fat birds might make for more successful offspring as well. Never mind the "assumption" part.
I don't think my comment proves anything. There will always be skinny bears in any population, it does not mean they are more athletic.
And I don't have a PhD. I found this point silly coming from you. Obesity in the arctic animal world has never been a problem. Until now .
I don't mean to be argumentative. I was in your country (while traveling from Ghana to Canada in the late 60's) a week before the russians took over. Love the site. Keep the faith.
Loveone doesn't neone doesn't need to be a PhD to understand that being as fat as possible isn't necessarily the most convincing proof of perfect healthed to be a PhD to understand that being as fat as possible isn't necessarily the most convincing proof of perfect health

reader Luboš Motl said...

I kind of knew you don't have a PhD. That was my point: even you should be able to understand the point that someone's being fat isn't a proof of his health. No offense intended, no pun included. I really wanted to say what I said, namely that one shouldn't need a PhD to understand such things. It's common sense, something we should share.

Well, I agree with you that being skinny doesn't imply being athletic, whether we mean bears or people or anything else. But equally important, being fat doesn't imply it, either. That's why the word "But" in your first comment in this thread was misleading.

Yes, that thing was an assumption, it was tested, and the tests actually falsified the assumption in that particular paper. It's still true that being fat has various disadvantages. I just grabbed the first paper that at least discusses these points. To see some more specific paper with the conclusion of the type I sketched, see e.g.

reader YeOldeMoptop said...

With the definitions of species that environmentalists use, a Yorkshire terrier is a different species than a Labrador retriever. Maybe that is defensible, IDK, but species are also defined by environmentalists by such characteristics as their diet and environment. By this reckoning, a field mouse that lives on a cattle ranch is a different species than one that lives in a wheat field.

It gets even more absurd. The polar bears survived the Eemian, this is based on fossil evidence, not DNA guesswork, during that time, when sea levels were much higher than today and temperatures were much warmer, it is highly unlikely that the Arctic was not ice free at times in summer. So this means that a polar bear who was born when there was sea ice and lived to when it was gone in fact changed species during its lifetime.

Defining species is a political act. It is a lot like defining when a "fetus" becomes human. The definitions are determined by the result in a political argument one desires.

reader brothersmartmouth said...

Please explain where I said "pure negative". I did not say that.
As far as demagogy is concerned, maybe you should point inward.

reader Luboš Motl said...

Hi, you didn't use the exact words "pure negative" but you wrote equivalent things, namely the sentence:

"But, the bears were looking thinner."

The word "But" means that the sentence that follows is believed by the speaker to act in the opposite direction than the previous sentences (which were "good news"), so the word "But" implies that you believe that the sentence about thinner polar bears may be assigned a sign and it is the negative one.

reader brothersmartmouth said...

Please explain how fat has "tons of reasons that make them bad" in the arctic.
And where does the "pure negative" quotation come from? I didn't say that.
Seems a bit over dramatic for a PhD.
"Extremely sloppy or dishonest or oversimplified". Thank you very much. I thought that is what your website was supposed to avoid. Guess not.

reader Luboš Motl said...

Wow, do these "redefined species" environmentalists really exist? A species boundary in science is defined by the inability to produce fertile offspring with members of another species. Everything in else is just non-scientific.

reader YeOldeMoptop said...

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are often used, such as similarity of DNA, morphology or ecological niche. "

I have seen the above used to argue that the polar bears we see today are a new species since the Holocene began.

reader bearded dragon behavior said...

Bears are most likely encountered when campers, hikers and fisherman head into the mountains or high country. Bears are very curious animals, but normally are not aggressive.