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Science

Squirrels Evolving to Suit Global Warming? 96

Posted by michael from the weird-science dept.
Gavinsblog writes "New Scientist is reporting that using a technique called quantitive genetics, researchers have found that due to the effects of global warming, female squirrels now give birth on average 18 days earlier in the year than their great-great-grandmothers. Is global warming also affecting human evolution?
"
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Squirrels Evolving to Suit Global Warming? More

Squirrels Evolving to Suit Global Warming?

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  • causality or correlation? (Score:5, Insightful)

    by jo-do-cus ( 597235 ) <johocus@zonnet.nl> on Wednesday February 12, 2003 @08:51AM (#5286749)
    What i dont get: where did they get the information that these changes are "due to global warming" ?? It's not like you can interrogate a squirrel to ask them why his genes are different.

    Probably the scientists saw the correlation with the changing climate and wrote that this would be 'a possible cause for that'. Journalists normally twist the meaning and content of scientific reports to make a nice headline, eventuakky becoming "Squirrels Evolving to Suit Global Warming".

    Generally, one cannot claim that species evolve for some purpose, and even if it would be so, then how do you prove that any change in genes is due to some cause??? It's all just correlations and some hopeful guesses, if you ask me.

    • "It's not like you can interrogate a squirrel to ask them why his genes are different."

      Can you do that to a human? I think that I know the basic mechanisms generating my genome from my parents, but I don't know why they are different.

      As I understand it gene changes are not fit a certain problem, but completely random. As a random change may be a change to the better, the survival of the fittest will make this change spread to more individuals in the next generation than a less fit gene.

      This does not rule out that the change in birth rate and pregnancy time has been fitter due to a change in the climate. But sience based on correlation is dangerous. It has been used before to "prove" lies.

    • Thats why I put a question mark at the end of the headline Jo. I would also find it hard to see a direct link.
    • I was skeptical about this at first, as well. But there is a bit of logic to it (just a bit). If it is warmer earlier in the year, it is possible for the pups to survive when born earlier. Typically, animals that are born prior to the last freeze don't have a good survival ratio. If the last freeze comes earlier in the year, pups born at earlier times have a better chance. It's logical, but there are holes.

      It is possible that this is a response to warming, but not an evolutionary response. Perhaps the squirrels mate earlier due to increased temperature. Also, this would be an easily saturable effect. Plants don't bloom in response to temperature, they bloom in response to ammount of sunlight. Since the Earth's tilt is still the same, the plants will still bloom at the same time. This means the pups may be alive & toasty warm, but with little/no food in the early stages of life. This would yeild smaller (or no) adults

      Although you are correct that evolution does not have a purpose, it does occur in response to change in the environment. It does not have the "intent" of adapting to he environment, but that is what winds up happening.

      Besisdes, this is probably popular media exaggerating a scientitst's claims again. I haven't read the real paper, but I would wager that the scientist worded things in less absolute terms. He probably said it appears to be due to global warming, or was strongly correlated with increased temperature.

      • The general problem with concluding a casual relationship from a correlational study is that it's not objective. the author can create any logic to explain the causal relationship.

        ie, take these facts. There are more computers produced every year.
        When computers are on, they create heat.
        The Earth is warming every year.
        Therefore, The increased existance of computers is causing global warming.

        This may seem insane, but it follows the same logic pattern as this story or any causaality based on a correlational study.
        Causality can only be determined with causal expirements.
      • What amazes me about these type of science rag claims is they help confuse an already poorly understood subject. Every time I read coverage about creationism in a science periodical that in the same issue has explanations of how evolution incorrectly works.
        Wasn't Lamark discredited over a century ago?
      • It is possible that this is a response to warming, but not an evolutionary response. Perhaps the squirrels mate earlier due to increased temperature. Also, this would be an easily saturable effect. Plants don't bloom in response to temperature, they bloom in response to ammount of sunlight. Since the Earth's tilt is still the same, the plants will still bloom at the same time. This means the pups may be alive & toasty warm, but with little/no food in the early stages of life. This would yeild smaller (or no) adults

        You are right that the change in squirrels behaviour is ulikely to be due to any genetic change. You are very wrong in your reported behaviour of plants. Plants are emerging and blooming earlier than they were.

    • Generally, one cannot claim that species evolve for some purpose

      My dad claims the human body evolved so it would fit perfectly on a motorcycle...
      ;- )

    • Yes, there is a casual relationship. The squirrels are causing global warming.
    • Journalists normally twist the meaning and content of scientific reports to make a nice headline

      The New Scientist is a habitual offender; most articles referenced to there from /. are hyperbole and sensationalism.

  • Global Warming?--Right... (Score:5, Interesting)

    by Henry V .009 ( 518000 ) on Wednesday February 12, 2003 @09:04AM (#5286802) Journal
    More accurately, New Scientist reports that Red Squirrels in the Yukon are evolving due to local climate change. Which it proceeds to call global warming.
    • Agreed.

      I must say I'm a bit surprised that most of the comments here seem to be in the "not global warming" camp. Must be that the doom-n-gloomers are still asleep?
      • Speaking for myself: I doubt the scientific quality of the article since it is unlikely that anyone can prove a link from something like global warming to the evolution of a squirrel. On the other hand, I will not deny that global climate changes exist and that they may have great consequences (whether it is all caused by pollution and whether all these changes are 'evil' is a whole different discussion). So please don't put me in the "not global warming" 'camp' just because I doubt this one article!!
        • Consider yourself out of the "not global warming" camp. I certainly wasn't trying to pigeonhole anyone. I was merely suprised that there weren't more (any?) handwavers pointing to this questionable article as "proof" of global warming.


      • > I must say I'm a bit surprised that most of the comments here seem to be in the "not global warming" camp. Must be that the doom-n-gloomers are still asleep?

        Sorry, I just wanted to snuggle under all those warm blankets for a few more minutes. What are we talking about today?

  • Evolution of human? (Score:5, Insightful)

    by Gadzinka ( 256729 ) <rrw@hell.pl> on Wednesday February 12, 2003 @09:08AM (#5286824) Journal
    Is global warming also affecting human evolution?

    There ain't no such thing as human evolution (anymore).

    The evolution is a trials and errors process. During the duplication of DNA sometimes something goes wrong and the result isn't a perfect copy of the original.

    This is called a mutation.

    As a result some function of the organism is different. The change may be beneficial for the organism or it may render it handicaped. For every positive mutation there are houndreds of thousands negative mutations.

    Who's to tell which mutations are positive and which are negative?

    Natural selection.

    If/when a particular mutation has some features that allow it to dominate gene pool it is positive. If the mutation causes premature death, sterility etc the faulty genes do not enter the gene pool. This is negative.

    In order for humans to evolve we would have allow natural selection to work. We don't do this. It is not the survival of the fittest for a long time.

    Robert
    • There ain't no such thing as human evolution (anymore).

      I agree that natural selection is past its prime in developing countries, but I don't believe evolution has stopped, or that evolution will ever stop. I think people are evolving more by societal selection than natural selection.

      In other words, now it comes down to who has more children, not who has children and who gets killed before they get the chance to (except those lucky Darwin Award laureates).

      So geeks are currently on the road to extinction! It is up to those who can to breed like rabbits to prevent this!

    • If/when a particular mutation has some features that allow it to dominate gene pool it is positive. If the mutation causes premature death, sterility etc the faulty genes do not enter the gene pool. This is negative.

      This statement is almost always correct but in the last couple of years I've become aware of a counterexample.

      I quote from a web page about MEN2 [cancerresearchuk.org]:

      Studies of Multiple Endocrine Neoplasia Type 2 syndrome (MEN2)

      MEN2 is an uncommon dominantly inherited cancer predisposition syndrome comprising tumours of C-cells of the thyroid, the adrenal medulla, and sometimes the parathyroid. The syndrome is due to activating mutations in the RET gene; inactivating mutations of the same gene are associated with Hirschsprung disease.

      Although the gene for MEN2 is dominantly inherited and almost invariably fatal, it continues in the gene pool because some sufferers live long enough to reproduce.

      Paul

      • If/when a particular mutation has some features that allow it to dominate gene pool it is positive. If the mutation causes premature death, sterility etc the faulty genes do not enter the gene pool. This is negative.

        This statement is almost always correct but in the last couple of years I've become aware of a counterexample.
        [...]
        Although the gene for MEN2 is dominantly inherited and almost invariably fatal, it continues in the gene pool because some sufferers live long enough to reproduce.


        That's probably one of the things that made me think that evolution of human has ended. I mean, what chance would the man carrying this gene have to reproduce if it wasn't for today's medicine?

        Of course he (or his genes ;) wouldn't be in problem if the gene was activated only after he is mature and with numerous offsprings.

        But then again, we weren't made to live a hundred years. We were made (by evolution) to create lots of offspring by 21 and die from tuberculosis at 25. What happens after 25 is bonus anyway ;)

        Robert
        • That's probably one of the things that made me think that evolution of human has ended. I mean, what chance would the man carrying this gene have to reproduce if it wasn't for today's medicine?

          Quite good, actually. And it's not just "the man", as the mutation is not on a sex-linked chromosome.

          Some of the people afflicted with MEN2 die of thyroid cancer before they reach ten years. Others die of it in their fifties, long after they've had many chances to reproduce.

          Paul

          • What about Huntingdon's Chorea? More common than MEN2, but doesn't usually present until the carrier is in his/her 40's, after (most) people who are going to have a family have a family.
    • LOL! Human evolution will stop when humans die out.
    • "This is called a mutation"
      I'm sorry but I need to say this... What your saying is that what we could have here is the x-gene!

      Sorry... I'm weak... just too weak... ;)

      I appolgise for the bad joke.

    • Evolution is not personal survival. It requires you to pass on your genes. Humans are evolving into creatures that can attract mates in crowded cities and suburbs.

      Modern medicine keeps people alive when they have problems that might otherwise have killed them, but this does not mean that natural selection is over. It just means that other genes become more important.

    • I don't mean to be crude, but... ah, heck, let's be crude, it demonstrates the point. Do you honestly believe that legless girls with three noses get laid as much as the more conventional folk?
      • Do you honestly believe that legless girls with three noses get laid as much as the more conventional folk?

        There is this Polish saying: ``kazda potwora znajdzie swego amatora''. Loosely translated it means ``every monster's gonna find itself a mate''.

        And I've seen several times, that they really do find a mate and often produce lots and lots of offspring.

        Robert

    • Re:Evolution of human? (Score:4, Insightful)

      by bill_mcgonigle ( 4333 ) on Wednesday February 12, 2003 @01:00PM (#5288358) Homepage Journal
      There ain't no such thing as human evolution (anymore).

      This statement assumes a static environment model, which is uncertain at best.

      Maybe we wipe out the ozone layer, and everybody with light skin dies young from skin cancer.

      Or maybe we blanket the earth with a nuclear winter or there's an mega-killer asterioid hit and everybody with dark skin dies from Vitamin D deficiency. Everybody in temperate climates dies too because it's too cold to grow crops, so only those smart/clever/ruthless enough to migrate south and grow food survive.

      For instance. There may not be any environmental pressures on human evolution at the moment, but that equalibrium is subject to being upset.

    • Evolution itself is evolving. With modern technology, humans are actively tinkering with natural selection. Apparently, this is a successful strategy, otherwise it would not work as well as it seems to.

    • Re:Evolution of human? (Score:2, Interesting)

      by JoeGee ( 85189 )
      There ain't no such thing as human evolution (anymore).

      I suspect it's the nature of life to adapt. In the past our technology has changed quicker than we could adapt to it, but in one area, diet, species change continues. Look at average weights of individuals in many "developed" countries. This is not an evolved feature, but if it persists through many generations it might very well change part of the human species. Adaptations that allow longer reproductive span of individuals who consume high calorie diets, such as better elimination of extra calories, or better tolerance of high blood cholesterol, might prevail. Adaptations such as a more dense bone structure or altered musculature (to carry the weight), might also occur.

      Unwittingly, or intentionally, in many "developed" countries we now segregate out lower functioning (borderline mentally retarded) individuals who in previous generations might have been able to lead "normal" lives. We put them in special schools/classrooms, we give them medications that change their behavior, and by artificially grouping them into separate social groups we decreased their chances of reproduction. I suspect any evidence to back this up would be anectdotal, but I'd wager if the numbers were there you would see a significant decrease in the number of borderline mentally retarded people who father or give birth to children.

      Similarly, although physical prowess is still a strong attractor, I'd be willing to bet that intelligent guys are sexier now than they have ever been. Although we won't live to see the results, you want to bet this subtle eugenics won't have an effect on the species?

      Just because we don't have lions hunting us on most golf courses doesn't mean the genome of h. sapiens sapiens won't continue to change. :)
    • We don't do this.

      Yep. Eyeglasses, contact lenses, and corrective surgery. One could argue that our gene pool is becoming "worse," from a hunter-gatherer standpoint.
    • Evolution is not about who gets killed. It is about who survives. Humans are just pooling largest selection of genes in our species history. By trying to save every human life, we are preserving genetic diversity in our species.

      The real problem is we have a finite amount of space and resources to mantain a large diverse population.
    • You tell em! all these damn cripples and tardos fuckin' up mah gene pool!
    • wouldn't the fact that there isn't much selection going on, provide us with a lot of diversity, that might ensure a fast evolution if some radical change occured?

      I mean... a lot of the genetic defects that are inconvenient but not directly lethal, could prove to be an advantage in the face of some particular disease...
      so while theres not much of a evolutionary pressure, we will probably be able to adabt really fast if something were to happen...

      oh... and it seems that we forget that there are also people living outside the united states and europe... life isn't necessarily as rosy red there...
      I know americans value their low oil prices, and right to cause global warming higher than their lives... but they are still human, and should (for the sake of completeness) be included in discussions about humanity as a whole.
    • All that is required for evolution to occur is for genes to vary and for that variation to have some influence on the number of offspring. Both apply to humans.

      The fact that humans have unique enviornmental conditions merely means that there are unique evolutionalry pressures on humans, not that they do not exist.

      -
    • That is so broad and general it doesn't even make sense anymore.

      We haven't stopped evolving. We just haven't had a major disaster to bottle neck the gene pool. we are always evolving (children). When a distaster does come along, and the people with n features/genes can survive and those without die, then there will be drastic changes in the future species.

      Trust me. we humans did not hit a plateau in our evolution.

      -eddie

  • Human Evolution... (Score:4, Insightful)

    by jsimon12 ( 207119 ) on Wednesday February 12, 2003 @09:11AM (#5286837) Homepage
    "Is global warming also affecting human evolution?"

    The envionment really stopped effecting human evolution once we started to manipulate it, so it is unlikely that you will see any similar effects in humans. If it gets to hot for us, we just crank up the AC.

    • If it gets to hot for us, we just crank up the AC.

      That's only true for the small percentage of "we" on this planet that can afford AC.

      • The point is the fact that humans change their environment rather then adapt to it, whether it be with AC, buffalo skin tents, white clothing or even a simple structure made from fallen branches. The last major physical thing we "adapted" to would probably be UV radiation and the production of vitamin D (hence the reason people have different skin colors).

  • Breaking News? (Score:2, Insightful)

    by gi-tux ( 309771 )
    I remember seeing this in gray squirrels growing up on the farm 30+ years ago. If food is available early then the squirrels had their litters early. If there were bad rains late in the season and the first litter was drowned, etc. then a second litter was usually delivered.

    I wouldn't call this anything evolutionary. It is interesting that their instinct takes care of this for them, but it isn't any kind of change. We have been lucky over the last few years and have had short winters (at least in the southern US) and that has changed the beginning of spring and most likely the birth dates of some animals.

    I bet that they spent a ton of federal money on that study too. Just another waste of taxpayer money trying to prove that God doesn't exist.

    • Just another waste of taxpayer money trying to prove that God doesn't exist.

      Looking for a state-sponsored theocracy? Try the administration of George W. Bush [washingtonpost.com] and his Helpful Friend, John Ashcroft [washingtonpost.com]!

      Scaring the bejeezus out of center-left citizens since January, 2000. :P
      -j

    • Species change in relation to their environment for reasons other than evolution. It's a fairly standard survival adaptation, but it can make for changes in species that people often think are best attributed to evoltion.

      In general, someone whose parents are both Pygmies but who grows up in Spain is going to end up being average height. Turns out a large portion of the reason why pygmies tend to be so short is their diet.

    • We have been lucky over the last few years and have had short winters (at least in the southern
      US) and that has changed the beginning of spring and most likely the birth dates of some animals.

      Well, some people do not call this 'luck' but 'global warming'.

      Your place is not the only place with relatively short and relatively warm winters.

      I remember winters with 30 degrees centrigrade below ZERO. To be precise: 3 or 4 winters in a row.

      And this is in the middle of europe, germany. Now we have sometimes for a week, -10 degrees. But the rest of the winter is *0* and only over night (sometimes) below zero.

      The average temparature might only be 1 degree higher than 20 years ago, the extream temperatures are *10* degrees higher(in winter) and about 5 degrees lower(in summer). This is my personal unscientific observation.

      The gulf stream is allready changing its shape.
      Despite similar high heat feeling produced by the sun, the air temperature close to the sea is lower than 10 years ago, and the water temperature about 2 degrees centigrate lower in the ares I go to vacation each year. The people living there confirm this by changed fish seasons and different "general wether situations" (e.g. no longer sun whole June, but rainy in the start etc.).

      angel'o'sphere

  • Bad News! (Score:2, Funny)

    by jfagan ( 228007 )
    For NASDAQ [nasdaq.com] that is, they have been hit [ncl.ac.uk] twice by those cute furry things. Once in 1987 and then again in 1994.

    In the UK office we still joke about it, much to the annoyance of the management :)
  • Did this change how they taste?

    If it's "Just like turkey!" or "bison!" I'm going to have to file a complaint with Darwin.

    Don't mess with "Just like chicken!"

    I work on a Help Desk, that's my excuse... ;)

  • Affecting evolution? Surely so! (Score:3, Funny)

    by mcgroarty ( 633843 ) <brian@mcgroarty.gmail@com> on Wednesday February 12, 2003 @09:49AM (#5287008) Homepage
    Is global warming also affecting human evolution?

    Yes. We get hungry for squirrel chili about 18 days sooner 'round here.

  • weather forecasting (Score:3, Funny)

    by HyperbolicParabaloid ( 220184 ) on Wednesday February 12, 2003 @10:12AM (#5287137) Journal
    Huh! I thought squirrels were doing well by foecasting if we would have a bad winter; now they are telling us we're going to have a tough millenium!!

  • You are all WRONG-GUH! (Score:3, Funny)

    by amarodeeps ( 541829 ) <dave@dubi t a b l e.com> on Wednesday February 12, 2003 @11:39AM (#5287711) Homepage

    Clearly GAWD-DUH is changing these little squirrels to fit his heavenly PLAN-NUH. Oh, he works in mysterious WAYS-UH. All of those SINNERS who believe in EVOLUTION-NUH will be shown the folly of their ways when the find themselves burning in the unholy HELL-FIRES of HELL-UH!!

  • city squirrels (Score:3, Funny)

    by Parsec ( 1702 ) on Wednesday February 12, 2003 @11:45AM (#5287761) Homepage Journal

    Anyone notice that city squirrels sometimes now pause on the dividing lines on streets? It would be an interesting experiment to transplant some UK city squirrels with US city squirrels to see if the side of the street we drive on is being genetically encoded.

    • That doesn't make sense. We drive on both sides of the road, just different directions per the lane.

      It might be noted that the squirrels are smart enough to be checking that they don't end up squashed, but I'm not sure they know the right-side-rule.

      • That's what I meant. Perhaps it's a cultural reference to say "they drive on the wrong side of the road"? The American driving on the wrong side in the UK and vice versa is practically a cliche on television (depending on the shows one normally watchs).

  • That Explains . . . (Score:1, Offtopic)

    by Dausha ( 546002 )
    Hey, that's it! I know understand why American youths today are so much more obese than of 30 years ago. It's not the sugar in our diet, the super-sized fries (always countered by the giant Diet Coke(R)), lack of self-control or self-esteem, or video games that cause it.

    Global warming is why we Americans are becoming fat-asses. This also probably explains why the rate of teen pregancy is on the rise, and the increasing use of heroine.


  • How do we know that it isn't premature births among squirrels that's causing global warming?

    • Of course the extra body heat they are giving of, not to mention the methane from extra farts.

      And of course more & larger squirrels mean larger fartier Foxes.

      MORE GLOBAL WARMING...

      Quick tell the newspapers, we will be on the morning news tomorrow. Government grant by Thursday...

      I say the only place we can do research is ohhhh .... the B.V.I.

      I'll bring the girls, you bring the booze.... Er... wait ...I MEANT to say I'll bring the research assistants you bring the sterilizing solution. Yea... yea... that's the ticket.

  • soon to publish my research (Score:3, Funny)

    by frovingslosh ( 582462 ) on Wednesday February 12, 2003 @03:27PM (#5289697)
    I have a small ($3 million) study grant from the E.P.A. and after careful study and review I've determined that global warming is caused by squirrels having their litter earlier and earlier.
  • Is global warming also affecting human evolution?

    In other news, scientists report that human evolution has taken its course and human many baby females will be able to reproduce every 18 days once they reach pubirty, effectively overpopulating the planet and showing it who's boss...
  • It just occured to me that climate-specific traits such as this one may be "purposely" fluid. It would make sense in that climate/environment tends to change quick relative to evolution (Ice ages and the like). A survival trait would be to lessen the preservation of a specific birthing pattern (or make it able to vary fairly quickly).
  • Then why hasnt squirrel season opened sooner?

    If you really want to know the truth about squirrels ask someone from VillePlatte,La
    They get off work and school for opening day. But then if global warming hits Louisiana like its aparently hitting canada all our squirrels will be dead after one 150 degree summer. Got to 115 here last year.

  • I've been investigating gestation periods with a variety of squirrels in the Ohio Valley, and not only haven't the periods changed over the last 10 years, but I haven't been able to get a single one pregnant yet.

    Maybe it's me.

  • The article is a bit thin on details. I presume the experiment kept test squirrels from each generation in a controlled temperature environment to ensure these aren't just squirrels with a "bonk when it's warm enough" gene? I've not seen squirrels with diaries, so I'd assume their behavior in these cases was controlled by their environment more than their genetic make up.
  • This doesn't need a genetic explanation. Maybe if an earlier birth is advantageous, then any mutations that help with this would become the norm. However, they may just be adaptive to the conditions. The fact that I have white skin is genetic, but the fact that I get up early on a Monday to put the garbage out isn't.
  • ...I hear that they're less likely to be married at the time. ;)

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