Notices
Results 1 to 15 of 15

Thread: Four-legged duckling - Evolution in action?

  1. #1 Four-legged duckling - Evolution in action? 
    New Member
    Join Date
    Feb 2007
    Posts
    2
    Hello all,

    I was reading the BBC news pages as I do when I came across the following story;

    http://news.bbc.co.uk/1/hi/england/h...re/6371901.stm

    It's about a four legged duckling. The story goes on to say that although rare, this "mutation" had been reported all over the world.

    I though this was an interesting story and it got me thinking. Is this evolution in action? Will in the next 1000, 100,000, 100,000,000 years we ducks with 4 legs as standard?

    And if so, why? Is this a start of a much greater plan of nature? Much like monkeys evolving?

    Perhaps I’m getting a little carried away (my level of science definitely falls in the “popular” category). But it really is fascinating.

    Thanks in advance,
    Neil.


    Reply With Quote  
     

  2.  
     

  3. #2  
    Guest
    It's a mutation, it occurs as they said. I suspect it is a mutation that fails everytime. For one thing the extra legs may be present but a whole lot of other would be needed to make them 'usable' these would include muscular and skeletal support. THis could just be a simpler form of 'siamese twins' where virtually the whole of the other embryo is absorbed. Interesting though.


    Reply With Quote  
     

  4. #3  
    New Member
    Join Date
    Feb 2007
    Posts
    2
    Oh well, there goes my "planet of the ducks" theory then
    Reply With Quote  
     

  5. #4  
    Guest
    Yeah, I should have added that if it was a 'siamese' mutation rather than a genetic anomoly then even if the little ducker survived and reproduced it would only pass on 'normal' genes. If somebody, anybody had already successfully reared ones of these to that point it would account for why there is no 'population of them' - if you think about it!

    I wonder if the little critter will be donated to science after it's brief attempt to become a quadraped?.
    Reply With Quote  
     

  6. #5  
    Moderator Moderator AlexP's Avatar
    Join Date
    Jul 2006
    Location
    NY
    Posts
    1,838
    i read that its not even a mutation: it was an embryonic development problem.
    "There is a kind of lazy pleasure in useless and out-of-the-way erudition." -Jorge Luis Borges
    Reply With Quote  
     

  7. #6  
    Forum Freshman
    Join Date
    Nov 2006
    Posts
    65
    Hi Neil,

    This is definitely not evolution in action. As was mentioned by Megabrain, this is not a genetic change that will pass through the germ-line and even if the change to four legs were to somehow give a survival advantage to this individual (which I seriously doubt because a duck with four legs will probably be a much less effective swimmer than with two legs), it wouldn't have any influence on his descendants. I'm guessing, but this might be due to a stem cell problem in early embrio development. At a certain stage in early development the cells are still all very similar and have the ability to develop into virtually anything. Two similar cells might therefore turn into a heart and a wing respectively. If something goes wrong at this stage a cell which was supposed to form a part of a muscle or skin for instance, turned into legs by "mistake". This type of change will thus not be represented in the sex cells and will not be passed to the next generation. This type of "mistake" will also almost always result in non-functioning limbs, because the extra legs will probably not be connected by the correct type of muscles to the correct places on the rest of the sceleton for it to work. In fact, most of the time an embrio starts developing like this the individual is not viable at all and a spontanious abortion will occur.

    I guess it's difficult to prove one way or the other, but another reason why this is not evolution in action is that unlike this example evolution is probably a subtle process with gradual, rather than sudden changes. On the other hand it might also be argued that sudden changes that give an immediate survival advantage are more likely to establish themselves and therefore change the genetic adaptedness of the whole species to it's environment, whereas small gradual changes will have so small an effect on the chances of that individual to have more descendants than it's peers that it will never become the norm.

    Sorry to have busted your hopes of cute little feathered quadropeds running around for your great grandchildren to play with, but this isn't going to happen! I don't think there has been even one example of an extra limb ever forming through evolution in any species (after the basic configuration of four limbs and a head with two eyes and ears etc has been set) for the whole history of earth, so that just shows you how unlikely (impossible) this is. In fact, I've heard this being mentioned as a criticism of the evolution theory - If there is not even one example of a species changing radically by the addition of an extra limb or two to form another new species, it looks like evolution might only be able tweak an existing species a bit but can't form brand new species or new forms of living things, so some other type of process was responsible for speciation!?
    Reply With Quote  
     

  8. #7  
    Forum Senior
    Join Date
    Jan 2007
    Posts
    321
    No, but think of the ducking as an 'extreme'. The outmost 1% of mutation. Now think the other way...the least 1% impact on the organism. Perhaps a 2% longer bill or eye iris ever so slightly different shaped pigmented.
    It's the non-extreme or subtle mutations that can impact a species in taking some evolutionary tangent.

    There's also a good point above about whether there is actual genetic mutation or was the the impact environmental on embryonic developmnet. That, however, can also be a form of genetic mutation at work. In this case genetic material either in the mother or embryo 'may' be more susceptable to certain influences in the environment than that of other individuals. Two individuals, for example, might be exposed to identical radiation levels but subtle differences in their DNA 'might' lead to different reactions.

    Some paleontologists in my field have argued that mutation itself is not haphazard but an evolutionary strategy for survival as much as any other. When a fish, for example, lays 10,000 eggs does she 'put all her eggs in one basket'? No, it's thought that among those 1000's are a few produced with subtle variations (mutations) that will be able to adapt ever so slightly better if environmnetal conditions are ever so slightly different than the norm. Instead of all 10,000 eggs dying because temperature is a half degree too cold....5 of those eggs are slightly different and can survive that half degree difference. Of course, those 5 eggs are just an insurance policy and probably the water temperature is fine for the other 9,995 offspring.

    The permutations of slight differences becomes part of survival strategy to carry on genetic lineage.
    Reply With Quote  
     

  9. #8  
    Forum Freshman
    Join Date
    Feb 2007
    Location
    The Netherlands
    Posts
    21
    hehe, i have to agree with the 2 posters above me, this has to have happened by some mistake in the womb(perhaps relatively common in this species of ducks)

    mutations are small changes in an organism's DNA. if, in one generation, these ducks suddenly got 2 more legs it must've been some kind of genetic manipulation :P

    such mutations have never been observed, and are a statistic impossibility
    grtz.
    -FaTaL_eRRoR
    Reply With Quote  
     

  10. #9  
    Forum Freshman
    Join Date
    Feb 2007
    Location
    Boston
    Posts
    8
    perhaps it was a faulty HOX gene? dont they tend to control growth of appendages. If this was the case, than maybe these 4 leggeded ducks have some sort of genetic abnormallity, or faulty maternal contributions even? Since this isnt the first 4 legged duck, it must have some sort of shared genetic characteristic for this to be happening?

    If that be the case, than surely some sort of evolutionary stressor is leading to this direction? so possibly this might have a weird evolutionary purpose, i dont know if the phenotype has worked itself out yet, but who knows..... maybe raising duck populations for production makes them heavier, so that they have more meat to sell. So this might have caused a stress on the legs, or support structure of the animal. Thus why not have 4 legs to take off the strain??? survival of the fittest :wink:
    Reply With Quote  
     

  11. #10  
    Forum Freshman
    Join Date
    Nov 2006
    Posts
    65
    Quote Originally Posted by Netrin
    perhaps it was a faulty HOX gene? dont they tend to control growth of appendages. If this was the case, than maybe these 4 leggeded ducks have some sort of genetic abnormallity, or faulty maternal contributions even? Since this isnt the first 4 legged duck, it must have some sort of shared genetic characteristic for this to be happening?

    If that be the case, than surely some sort of evolutionary stressor is leading to this direction? so possibly this might have a weird evolutionary purpose, i dont know if the phenotype has worked itself out yet, but who knows..... maybe raising duck populations for production makes them heavier, so that they have more meat to sell. So this might have caused a stress on the legs, or support structure of the animal. Thus why not have 4 legs to take off the strain??? survival of the fittest :wink:
    Remember that evolution and the gene's that cause it is blind. When you say that some sort of evolutionarry stressor is leading in this direction, you're possibly attributing some sort of foresight to the mutation (or I might have misunderstood you because of you not elaborating too much?). Mutations are completely blind and can't be forced to happen more often by environmental pressure.

    The correct way to describe this is that once the mutation happened randomly, it will be tested by the environment to see if it improves the survival potential of the individual, which might then gradually become the norm of the whole species.

    All of this is however very hypothetical as far as this example is concerned, because I seriously doubt if this is a trait that will be passed to offspring.
    Reply With Quote  
     

  12. #11  
    Forum Senior
    Join Date
    Jan 2007
    Posts
    321
    Quote Originally Posted by Burger
    Quote Originally Posted by Netrin
    perhaps it was a faulty HOX gene? dont they tend to control growth of appendages. If this was the case, than maybe these 4 leggeded ducks have some sort of genetic abnormallity, or faulty maternal contributions even? Since this isnt the first 4 legged duck, it must have some sort of shared genetic characteristic for this to be happening?

    If that be the case, than surely some sort of evolutionary stressor is leading to this direction? so possibly this might have a weird evolutionary purpose, i dont know if the phenotype has worked itself out yet, but who knows..... maybe raising duck populations for production makes them heavier, so that they have more meat to sell. So this might have caused a stress on the legs, or support structure of the animal. Thus why not have 4 legs to take off the strain??? survival of the fittest :wink:
    Remember that evolution and the gene's that cause it is blind. When you say that some sort of evolutionarry stressor is leading in this direction, you're possibly attributing some sort of foresight to the mutation (or I might have misunderstood you because of you not elaborating too much?). Mutations are completely blind and can't be forced to happen more often by environmental pressure.

    The correct way to describe this is that once the mutation happened randomly, it will be tested by the environment to see if it improves the survival potential of the individual, which might then gradually become the norm of the whole species.

    All of this is however very hypothetical as far as this example is concerned, because I seriously doubt if this is a trait that will be passed to offspring.
    True. (However, i think Netrine was being witty.)

    Your comment addreses the most common misunderstanding of evolution and that is one of purpose and direction. This is made sometimes in predicting the future of human evolution where we are all mistakedly assumed to have bigger brains, limbs atrophy and so on. Do the most intelligent in your modern society have the most children who, themselves, go on to breed?

    Similarly with some future colony on Mars, etc. A thousandth generation Martian would be no more adapted to live on Mars than a second generation unless there was selective breeding and selective medical intervention.
    Reply With Quote  
     

  13. #12  
    Forum Freshman
    Join Date
    Nov 2006
    Posts
    65
    Your comment addreses the most common misunderstanding of evolution and that is one of purpose and direction. This is made sometimes in predicting the future of human evolution where we are all mistakedly assumed to have bigger brains, limbs atrophy and so on. Do the most intelligent in your modern society have the most children who, themselves, go on to breed?

    Similarly with some future colony on Mars, etc. A thousandth generation Martian would be no more adapted to live on Mars than a second generation unless there was selective breeding and selective medical intervention.[/quote]

    Interesting point about the most intelligent people not producing the most children. We've been discussing this same thing in another thread a few weeks ago. It seems to me that social development become a negative selector once it reaches a certain level in human societies (based on the severe decrease in the average amount of children in "advanced" societies). It is however very early days now and there's only been about two generations with this decrease in reproduction, which means nothing on an evolutionary scale. I also made the point that even though the more "advanced" societies might be less successful at the moment if you look purely at their reproduction rate, a future global catastrophy might show that the more advanced societies are better equipped to handle change (adaptable vs adapted) because of better infrastructure and foresight (which is to a large extent the result of higher intelligence and development) and that the apparent selection against advanced societies will be shown to be the stronger phenotype eventually. All of this is based on the presumption that there is really a significant genetic basis for the differences between "advanced" and other societies and that it isn't in fact ony the result of different social and cultural characteristics.
    Reply With Quote  
     

  14. #13  
    Guest
    Maybe it was just a genetic typo, you know, Quad Quad instead of Quack quack.....
    Reply With Quote  
     

  15. #14  
    Forum Freshman wonkothesane's Avatar
    Join Date
    Feb 2007
    Location
    Brisbane, Australia
    Posts
    47
    Even supposing this was a mutation and not an embryonic mishap as has been suggested these kinds of "macro-mutations" have little chance of benefitting the organism. Apart from the good observations that the duck's extra limbs would not fit well with the rest of it's anatomy I would also suspect that the duck's brain is ill fit for coordinating them (two left feet? ).
    Fry me a kipper skipper, I'll be back for breakfast!
    Reply With Quote  
     

  16. #15  
    Guest
    Wouldn't survive in the wild, hell, along comes a predator and the damn thing tries to run in two different directions at once...
    Reply With Quote  
     

Bookmarks
Bookmarks
Posting Permissions
  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •