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Thread: Why do so many guillemot fledglings fail their first flight?

  1. #1 Why do so many guillemot fledglings fail their first flight? 
    Forum Freshman GreatBigBore's Avatar
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    I'm watching Attenborough's "Life of Mammals" for the zillionth time. Man, I love that guy.

    Anyway, in the Arctic, baby guillemots must take their first flight off the cliffs down to the ocean (at around 10:00 into the clip). But there's a lot of land between the cliffs and the ocean, and many of the guillemots fail to make it all the way to the water. These are picked off by the arctic fox.

    The fact that so many fail seems to me to carry some meaning. In an oversimplified situation, one might expect that natural selection long ago would have weeded out those who couldn't survive their first flight to the water. So there must be some evolutionary reason for so many to fail. There must be some other aspect of guillemot childhood that is precariously balanced against the ability to survive one's first flight.

    But I can't imagine what this aspect might be!

    Could it be that the chicks have very little time to build up enough wing muscle to survive the first flight? Growing wings that can slam-dunk the first flight requires more food than the parents can provide during the short growing season? I'm not so much looking for a solid answer (unless someone has such an answer readily available) as looking for a discussion of the possible reasons. Thoughts?


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  3. #2 Re: Why do so many guillemot fledglings fail their first fli 
    Forum Masters Degree Twit of wit's Avatar
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    Quote Originally Posted by GreatBigBore
    The fact that so many fail seems to me to carry some meaning. In an oversimplified situation, one might expect that natural selection long ago would have weeded out those who couldn't survive their first flight to the water. So there must be some evolutionary reason for so many to fail. There must be some other aspect of guillemot childhood that is precariously balanced against the ability to survive one's first flight.
    You are wrong. Evolution does not work that way. Changes don't arise because they are helpful. Changes are random. Yes, mutation that would give them 100% chance would quickly prevail, but it can happen only after such mutation arises by chance.


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    Twit, I don't see that the OP even implied that selection has such capability. The OP is wondering what accounts for the observation that even today after many generations, many don't have the characteristics that would cause them to make it to the water. Despite the fact that many clearly do have the requisite characteristics.

    From this basic observation we can readily conclude that the requisite traits do exist for selection to act on and therefore if selection is the force that is claimed why has it not done its job?

    The OP is surmising that factors other than ability to make it to the water must be balancing or competing.
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  5. #4  
    Forum Masters Degree Twit of wit's Avatar
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    Quote Originally Posted by cypress
    From this basic observation we can readily conclude that the requisite traits do exist for selection to act on
    Wrong.
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    Forum Professor Zwirko's Avatar
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    GreatBigBore, the clip is talking about one specific colony of these birds, which look like Uria aalge to me. The Isle of May which is not too far from where I live, has a Guillemot colony (also Uria aalge). There are neither beaches below the cliffs nor foxes there.



    Many of these birds don't spend their whole lives at one colony either. Some animals just happen to make a living in precarious situations. As a group, the birds are successful and the loss of "a few" chicks is not that significant in the grand scheme of things.
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    Quote Originally Posted by Twit of wit
    Quote Originally Posted by cypress
    From this basic observation we can readily conclude that the requisite traits do exist for selection to act on
    Wrong.
    That's an odd thing to say. How could any make it to the water if they don't have the requisite traits to do so? Answer is that some do have the traits. It is even possible most do. I think your accusation falls flat.

    Meanwhile Zwirko provided an excellent response to the question by showing that overall selection for ability to fly past the beach may not be as important as we might have thought.
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  8. #7  
    Forum Masters Degree Twit of wit's Avatar
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    Quote Originally Posted by cypress
    Answer is that some do have the traits.
    Succes does not depend only on genes.
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  9. #8 Re: Why do so many guillemot fledglings fail their first fli 
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    Could it be that the chicks have very little time to build up enough wing muscle to survive the first flight? Growing wings that can slam-dunk the first flight requires more food than the parents can provide during the short growing season? I'm not so much looking for a solid answer (unless someone has such an answer readily available) as looking for a discussion of the possible reasons. Thoughts?
    Perhaps the wing stubs of chicks aid in balance and coordination. Maybe early cerebellar development is also involved. The reason I say this is that so many young chicks fall by the wayside via falling down and becoming vulnerable or becoming disoriented.
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    The situation is that the advantages of that particular nesting site outweigh its drawbacks, for the guillemots who nest there.

    Where is the mystery? Are we supposed to be assuming that there would be no cost associated with overcoming the flight test? That natural selection on these birds operates only on the flight ordeal that we are paying attention to this week? That every selection pressure can be met by modifications available to the organism?

    It's bad enough when "just so" stories are presented as actual evolutionary paths. When "just not so" stories are presented as challenges to standard theory, we are in the realm of the crackpot.
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    The situation is that the advantages of that particular nesting site outweigh its drawbacks, for the guillemots who nest there.
    What leads you to believe that some of the traits certain young chicks possess might not lead an increased chance of survival? I doubt it's based entirely upon the site of the nest.
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  12. #11  
    Forum Freshman GreatBigBore's Avatar
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    At about 19:00 in the same video (the "Opportunists" video), there is a similar situation with a different species. This time, it's bats instead of guillemots. Attenborough describes how many newborn bats fall from the ceiling to be eaten by skunks and raccoons. Again, a naive expectation would be that the bats who tend to fall in infancy should be weeded out fairly quickly, resulting in a population that is really good at staying safely attached to the ceiling.

    There must be something that balances against the likelihood of falling to the floor. I'm sure that there are examples of this all over the animal kingdom, such as why the cheetah isn't five miles per hour faster, but that trade-off seems more obvious: more speed would mean more body heat, for example, which would have to be dissipated. I wonder what the trade-off is for newborn bats holding onto their perches.

    More thoughts, anyone?
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    Well, the bats do consist of a population that is really good at staying safely attached to the ceiling - that's why the bats haven't all been eaten by racoons yet. Those that do fall are the sick and the unlucky. If you think about it, then you can see that they are indeed weeded out - all those that survive are those that are stuck to the ceiling. Falling or loosing ones grip is probably something that can't be eliminated entirely. Again, like the Guillemots, you need to look at the population as a whole - the vast majority of the bats hold on to the cave roof just fine and live successful lives.
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    Quote Originally Posted by Twit of wit
    Quote Originally Posted by cypress
    Answer is that some do have the traits.
    Succes does not depend only on genes.
    No, but gene configuration is a necessary condition.
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    Quote Originally Posted by gottspieler
    The situation is that the advantages of that particular nesting site outweigh its drawbacks, for the guillemots who nest there.
    What leads you to believe that some of the traits certain young chicks possess might not lead an increased chance of survival? I doubt it's based entirely upon the site of the nest.
    Yes, Iceaura's statement is as presumptive as the one complained about. Only Zwirko's explanation is testable. If the colonies do intermix, that is the colony shown in the film is not reproductively isolated, then interbreeding accounts for the high failure rate.
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  16. #15  
    Forum Masters Degree Twit of wit's Avatar
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    Quote Originally Posted by cypress
    Quote Originally Posted by Twit of wit
    Quote Originally Posted by cypress
    Answer is that some do have the traits.
    Succes does not depend only on genes.
    No, but gene configuration is a necessary condition.
    ??
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  17. #16  
    Universal Mind John Galt's Avatar
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    Great BIg Bore,

    TANSTAAFL

    That explains everything.
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    Indeed Ophiolite.
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  19. #18  
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    The price of adaptive change via a process of random variation and selection is that you have to take many throws of the dice at each generation, and most of them have to fail. We shouldn't be surprised to see that continuing at any point in time, regardless of how long the process has been at work.
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    Quote Originally Posted by TheBiologista
    The price of adaptive change via a process of random variation and selection is that you have to take many throws of the dice at each generation, and most of them have to fail. We shouldn't be surprised to see that continuing at any point in time, regardless of how long the process has been at work.
    Zwirko's hypothesis is testable and it fits observation and uniform experience. Can you offer a mechanism to test and falsifiy your explanation?
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    Quote Originally Posted by cypress
    Zwirko's hypothesis is testable and it fits observation and uniform experience. Can you offer a mechanism to test and falsifiy your explanation?
    Please refer to the last one hundred and fifty years of biological research. You will find numerous examples of what you are (to blind to see) looking for there.
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    Quote Originally Posted by Ophiolite
    Quote Originally Posted by cypress
    Zwirko's hypothesis is testable and it fits observation and uniform experience. Can you offer a mechanism to test and falsifiy your explanation?
    Please refer to the last one hundred and fifty years of biological research. You will find numerous examples of what you are looking for there.
    No I don't think so. Edit: There is a plethora of great research over the years but it doesn't seem to address this issue; much of it seems to avoid this question.

    See Biologista's description begins with an absolute that selection accounts for the diversity we observe but then describes why it is unable to do something that should be simple. The research does not help with this question. However referring again to Zwirko's model it adequately explains how competing factors dilute the presumed power of selection of isolated advantage and it is testable. I would like to see a simple explanation and a description of how Biologista's conjecture might be tested. Referring to authority by hand waving at some unnamed research doesn't cut it.
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    Quote Originally Posted by gottspieler
    What leads you to believe that some of the traits certain young chicks possess might not lead an increased chance of survival?
    Nothing - I don't believe any such thing.

    I'm simply pointing out that assuming some particular small set of those, whose nature you have not investigated or described, are the overwhelmingly critical factors in guillemot reproductive success, at this nesting site or anywhere else, is ridiculous. And the claim of some mysterious failure of Darwinian process here rests on that assumption, among several others equally dubious (such as that the guillemots are not in fact evolving - what was the first flight failure rate a thousand years ago?).
    Quote Originally Posted by cypress
    Yes, Iceaura's statement is as presumptive as the one complained about. Only Zwirko's explanation is testable. If the colonies do intermix, that is the colony shown in the film is not reproductively isolated, then interbreeding accounts for the high failure rate.
    So first you find presumption in my criticism of your previous presumption, and then you make a howler of a further presumption as a bald assertion (that such and such a factor, if present, "accounts for the high failure rate"). Sweet.

    Many possible explanations are testable, Zwirko's among them. So?
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  24. #23  
    Forum Radioactive Isotope skeptic's Avatar
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    The thing about using TV documentaries as a data source, in spite of the reverence we all hold the Great Attenborough in, is that it is non quantitative. The camera men and women spend literally weeks filming, and they capture everything that might be dramatic. At the end of the day, the chicks that fall may be a tiny minority.

    Once we are made aware of this fact, the mystery disappears. It becomes an artifact of sexual reproduction. The whole point of sexual reproduction is that it creates random variability. Some of that variability, in spite of natural selection, makes individuals less fit.
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  25. #24  
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    To the OP, and forgive me, as I have only scanned the replies quickly...but perhaps they are as they have been, and changes within their environment are outpacing adaptive evolution.

    Just a thought.
    "Let your anger be as a monkey in a pinata, hiding with the candy, hoping the children do not break through with a stick."

    "If you can't explain it simply, you don't understand it well enough." *Einstein
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  26. #25  
    Forum Freshman GreatBigBore's Avatar
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    Quote Originally Posted by Ophiolite
    Great BIg Bore,

    TANSTAAFL

    That explains everything.
    Well, yeah, but I'm trying to understand the free lunch mechanism a little better. You're right that the fledgling guillemots can't succeed in their first flight for free. What I'm trying to figure out is what they have to pay in order to have a successful first flight, what they had to sacrifice in order to succeed. I hypothesize that if there were such a thing as a free lunch, or even if there were an easy way to guarantee a successful first flight, then more birds would succeed. So what I'm really trying to figure out is what the trade-offs are that make the first flight such a risky venture.

    For example, maybe stronger wings would solve the whole problem, but stronger wings would require more food, and the breeding habits cause all the available food to be used up. Stronger wings aren't an option when your neighbors are eating all the food that you need for your stronger wings. Dawkins talks about the evolutionarily stable strategy, or ESS, in The Selfish Gene. If a single deviant guillemot parent pair worked harder to get more food for their baby in order to ensure stronger wings, they would have less time to get food for themselves and might, for example, starve to death before they had a chance to strengthen their chick enough for a successful first flight.

    So the ESS here is to grab as much as you easily can and feed as much of it as you can afford to your chick, and hope for the best. Same as all other ESSs: hope for the best.

    I'm having the same question about the baby bats who fall from the roof of their cave: what is the trade-off that makes their lives so precarious, that makes it just slightly more likely for them to fall. Seems like there would be several easy ways to make them stick to the ceiling better, but all of those ways would have a cost, as you have pointed out. Presumably, the cost of sticking to the ceiling better would have to make the babies less likely to survive in the future. I'm trying to figure out what kind of things would make them less likely to survive due to their investment in sticking to the ceiling.

    Does that make any sense at all?
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  27. #26  
    Forum Radioactive Isotope skeptic's Avatar
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    GBB

    What you said makes sense, and there may be a lot of truth in it. However, there is a Great Big Assumption underlying your logic that you need to recognise. This is the fallacy that too many people operate under, when considering matters evolutionary.

    The assumption is that the process of evolution is perfect or approaches perfection. This is so far from the truth that is needs a reminder often. Evolution is a highly fallible process. Evolution makes mistakes, all the time.

    Evolution is based on sexual reproduction and mutation, leading to genetic variability that is as close to random as makes no difference. Random variability leads to an immense number of errors in the way genes are expressed.

    A lot of those young bats and birds are simply genetically different in ways that are counter-survival. They will be selected out of the gene pool, but those differences will reappear.

    In addition, another 'imperfection' of evolution is that a lot of what goes on is not selection at all - just the operation of random chance.

    Sometimes, what we observe is not the operation of natural selection at all. Just random genetic expression, and survival or death by chance factors.
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  28. #27  
    Forum Sophomore LunchBox's Avatar
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    Quote Originally Posted by skeptic
    GBB

    ...The assumption is that the process of evolution is perfect or approaches perfection. This is so far from the truth that is needs a reminder often. Evolution is a highly fallible process. Evolution makes mistakes, all the time.
    The "Red Queen" argument..."you" must change as fast as you can as not to fall behind...as far as I can tell evolution can only keep pace ith their environment...if not, another one bites the dust.
    "Let your anger be as a monkey in a pinata, hiding with the candy, hoping the children do not break through with a stick."

    "If you can't explain it simply, you don't understand it well enough." *Einstein
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