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I fail to see what exactly is stopping Polar bears from adapting....
Perhaps it is simply a fable that they cannot....
I've been thinking about your question, because it is a legitimate one that goes to the core of why the bears are important. I thought of an example that may illustrate my point about the genetics. There is a small moth that lives in New England. It spends much of it's time on the bark of birch trees where its grey-white color is a perfect camouflage. The birds don't see it so they don't eat it. It's not too great a leap in logic to suppose that a moth born colored black would be more likely to be eaten. During the early days of the Industrial Revolution coal soot blanketed large portions of that part of the country. The bark of the birch trees became blackened with it. Within a few generations, the color of the moths had changed to black, as it had become the white moths that were then more likely to be eaten. Time passed, and smokestack "scrubbers" and other technology took much of the soot out of the air. The birch bark was again white and so were the moths, because the black ones were eaten by the birds.
This illustrates the modern view of evolution; a species in a stable environment remains more or less the same, even for thousands of years. Given a sudden change in the environment the species will suddenly change in order to survive. The key though, is the fact that the moths possessed both the "black" and the "white" gene to begin with. Otherwise, the only way they could change would be through random mutations which require much more time. Given that the birds were the "driver" of this example of adaptation, the moths could not have adapted fast enough to survive.
That returns to the polar bears. They are experiencing a similar change to that of the moths, on a similar time scale. If they still retain ancestral genes permitting survival in other environments they will survive. If not, they probably won't at least not without help.
So from that standpoint you can consider the argument made by some that this is just the natural order and nothing to react to. What after all would be wrong with a planet inhabited only by us and a dozen or so other species? Wouldn't that just prove they were "fitter"? The thing that has enabled people and other species to survive to this point is genetic diversity, as in the simple example of the moths. Especially in the US we have a pattern going of replacing thousands of species within a given geographic area with a dozen or two ("monoculture"). Often even the ones that remain have been bred or cloned to have the least genetic diversity possible. Like the moths, this makes life more vulnerable to any change in the envoronment, even small ones.
There have been six mass extinctions, the last being sixty million years ago. Species are going extinct right now at a higher rate than during any of the previous mass extinctions. Whether the loss of diversity is the cause or simply a catalyst, there is no doubt that the survival of each species adds to the chances of the survival of all, including us, just as the extinction of any detracts from the chances of survival of all, including us.
Evolution takes thousands of years. Climate change will destroy polar bear habitat in 20 years, or less--but some say they have until 2050. No, they cannot adapt. They will become extinct (except for the polar bears in zoos). Basic science.
They have ICEE machines behind their fake cages. They have their own 7-11 clerks, too. The reason the bears are so fat is that they gorge themselves on Twinkies and ICEEs. Sadly, these bears can never be returned to the wild, because there are no 7-11s in the Arctic. They would starve without Twinkies.
So, since the bears have to have ICEEs and Twinkies, I've started a movement, Twinkies for Polar Bears, to gather food for these majestic animals. Won't you donate, please?
It isn't a matter of something stopping them, so much as they simply face longer odds than other species in similar straits because they have never lived in any other conditions. Presumably somewhere they had a pre-ice age ancestor with the genes to survive under other conditions, hopefully those genes have not been bred out of the current strains of the species, and they will be able to adapt.
Human's have an advantage in that our ancestors were both nocturnal and diurnal at different times, tree dwelling and ground dwelling, denizens of the deep forest and open plains, as well as a fairly wide temperature range. This gives us a very diverse gene pool to draw on to meet new environmental challenges.
I've seen shows and read information that certain families of bears have adapted to eating bird eggs on land and it has partially if not altogether replaced a source of protein.
Excellent observation. Can't wait to see how MF gets herself out of the straightjacket.
Man has already re-introduced many threatened species back into the wild from (stocks kept in zoos and private owned rearing locations) and they are thriving.
People think polar bears aren't able to adapt based upon what exactly,that they are white and live in or near ice?
I don't know what people think. Remember not just the ice, but the whole ecosystem that supports them will be gone. They'll be limited to what they can catch at the shoreline, or even inland. They will have to come up with a whole new reproductive cycle as far as where they bear and raise their young. They will face a competitor for in the alpha role in the better-adapted Grizzly as well as many smaller predators that will prey on their young. Like I said, a lot of how well they deal with that that depends on what genes they have retained from their ancestors and what ones have been bred out over the Centuries. And as I also said, my expectation is that small breeding populations isolated from one another geographically will survive. Without only small numbers they will remain permanently dependent on Man to relocate specimens from one area to another to keep the gene pools viable. All of these small populations will be vulnerable to diseases, etc. in ways they aren't today (because of the lack of diversity),
Where is a CD resident zoologist/ Polar Bear expert when we need them?
As to adapting - looks like the bears are adapting to eating whale meat (per the report below).
OK, good grief, did we recently change regs to save the bear or use it as another tool in the push for implementing measures against climate change? (See report below - before someone jumps on me - they said it).
* Zoologists disagree over the extent to which rising temperatures are detrimental to the polar bears.
* Scientists lack reliable observations because regions are hard to reach, especially Russia's eastern Arctic and eastern Greenland.
* Biologist is to soon track bears by a GPS collar so they can monitor them.
* Rough estimates say about 25,000 polar bears live in 19 different populations in the north polar region with 60 percent of them in the Canadian Arctic.
* Scientists are having a hard time determining if individual populations are growing or shrinking.
To determine this, they need reliable past data.
*In western Hudson Bay area, they say bear decrease is 22 %
* Some populatons of bears are increasing or stable.
* Bears still hunted the most in southerly ranges in Canada, where receding ice poses the greatest threat to the animals.
* Bears are now adapting in their eating habits by eating dead whale.
Quote:
The Inuit official believes that the scientists' warnings are exaggerated ... they have thousands of years experience in fighting polar bears, ...........They claim that the populations they have seen recently on their hunting trips are unusually high, http://www.spiegel.de/international/world/0,1518,613637,00.html
Quote:
Two weeks ago, President Barack Obama reversed his predecessor's policy. From now on the polar bear will receive stronger legal protections, which, under the US Endangered Species Act, could lead to measures against climate change. http://www.spiegel.de/international/world/0,1518,613637,00.html
Quote:
It is completely false to portray polar bears as victim of climate change because they seem almost shipwrecked as they drift through the Arctic Ocean on broken-off ice floes. "The bears love to travel longer distances on drifting ice," says Derocher, setting the record straight. http://www.spiegel.de/international/world/0,1518,613637,00.html
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