Optimistic Optics: Scientific American Makes Bold Claims About the Origin of the Eye

_{Jonathan McLatchie

June 23, 2011

Intelligent Design}

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A couple of weeks ago, an interesting article appeared in Scientific American, titled “Evolution Of The Eye.” The subheading of the article makes the bold claim, “Scientists now have a clear vision of how our notoriously complex eye came to be.” Read More>>>

Comments

Yes, I agree, Mung. I was using the word in the sense in which it is used in population genetics, aka "beneficial". "Beneficial" only means that a mutation increases an organism's chance of survival. It doesn't mean that it will enjoy life more (indeed it may enjoy life less). Ditto with "disadvantageous" and "deleterious". I should also point out that "advantageous" and "beneficial" are also used only with respect to the current environment. And so a series of mutations that enable a Giant Panda to live solely on bamboo shoots, at the expense of being able to survive on anything else, is advantageous to the Panda, only as long as there is plenty of bamboo. Similarly, losing a vitamin C gene is not deleterious/disadvantageous to a primate as long as the population lives in an environment with plenty of fruit and veg. In both cases, however, if the environment changes (the bamboo groves are depleted; the primate goes to sea on ships for long periods) that genotype becomes deleterious. I will try to make this clear in future, although it is standard terminology. In most species, it doesn't make a lot of difference, but I agree, when we talk about complicated organisms like human beings, it matters. It may be hugely advantageous to me to be part of a population with a genotype that confers the intelligence to develop, and make available to me, birth control methods, but it isn't advantageous to my genotype. As a result, my population will probably evolve to have a later fertility window. That might be a nuisance to some people, but it will be advantageous to the population in population genetics terms. I'm sorry if this has not been clear to you from my posts. I hope it is now understood between us. I will henceforth reserve the term "personally advantageous/beneficial" for a trait that merely increases life enjoyment/fulfillment and "genetically advantageous/beneficial" for a trait that increases the probability of the propagation of a genotype, in the current environment, relative to either an immediate or remote ancestral genotype.Elizabeth Liddle_{June 26, 2011
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It really does seem to me that you repeatedly misunderstand what I’m saying, then accuse me of changing what I’ve said!
But not in this case, right? I simply asked you to clarify yourself. I even acknowledged that's how you meant it: "But that’s not what you meant by it at all. What you mean was, I leave more offspring than you." I pointed out that most people don't think of "advantageous" in terms of leaving more offspring than others. Why am I wrong? So to avoid confusion, which is what you say you're trying to do, you should perhaps avoid using "advantageous" when you simply mean to say that there's a reproductive differential. That way I won't have to worry about whether or not you're equivocating. :) An advantageous mutation is a mutation that provides some advantage to the organism. OR An advantageous mutation is a mutation that appears in increasing frequency in the population over time. You do agree there is a difference in those two statements don't you?Mung_{June 25, 2011
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Mung: If we really want to have fun, if two rabbits have 4 offspring, and they all survived, then in the 5 millionth generations we'd have 2^5,000,000 rabbits born! I'm licking my chops!PaV_{June 25, 2011
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Mung:
In the sense that they confer greater net reproductive advantage.
Well, why didn’t you just say so. I mean it’s not like I haven’t been complaining for weeks now about how you keep shifting the way you speak about selection.
Sheesh, Mung, when I have I said anything different! I must have said this a thousand times! Well, perhaps not a thousand, but every time I've mentioned a distribution of selection coefficients (as in all that discussion about Sanford) that is what I've been talking about - selection coefficients. Obviously, it might be an "advantageous" to me, personally, for example, to be able to control, but it's not "advantageous" for my genotype. Ditto with heritable personal advantages that don't confer greater probability that my genes will be passed on. It really does seem to me that you repeatedly misunderstand what I'm saying, then accuse me of changing what I've said! Natural selection has a single definition, and I haven't strayed from it. If you think I have, then there has been a miscommunication. I take, as I've said, partial responsibility for that, but it takes two to tangle.
When us normal folks think of an advantage, we think of the advantage one organism has over another. You know, as in, I can run farther, jump higher, and hold my breath longer than you. But that’s not what you meant by it at all. What you mean was, I leave more offspring than you. Now how that’s more advantageous to me, I don’t know, especially if I have to support them all.
Right. So now we are clear, I hope. Good.Elizabeth Liddle_{June 25, 2011
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Dr Liddle: Would you repost your answer and tell me for which parts you have actual data/hard numbers? For instance, when you say "...That’s the only criteria for “correctness” of the order...", it seems to me that is over simplifying the process. Do we know from experiment the number of mutations that end up being dead ends because none of the next ones would be advantageous? Or "...But we know that fitness landscapes are very high-dimensioned – indeed we are talking about multiple dimensions here...Once you have multiple dimensions, while there remain “traps” in the landscape, they are fairly rich traps....". Doesn't this make matters worse, since every dimension adds a new set of parameters that must be tinkered with, creating even more local maxima?snelldl_{June 25, 2011
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Just for fun, let’s pretend that we have two rabbits who breed and leave two offspring, which in turn breed, and leave two offspring.
Sir! You do not know how to have real fun. Instead, let's pretend that we have two rabbits who breed and leave four offspring. Two of those rabbits breed and leave four offspring. The other two breed and leave 4.01 offspring. Now that, sir, is evolution.Mung_{June 24, 2011
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Mung:
The idea that advantageous mutations inexorably move to fixation is a myth.
Just for fun, let's pretend that we have two rabbits who breed and leave two offspring, which in turn breed, and leave two offspring. Let this go on for 5 million generations---would that be about 1.3 million years. Assuming, as we're told, that there are about 100 mutations per generation, and that there are about 99 harmful mutations to every beneficial mutation (conservative estimate I would think), then the genomes of the offspring would have 99% harmful mutations and 1% beneficial mutations. Something is wrong with this picture, isn't there? Somewhere along the line, the offspring would have both died, and the lineage with it. ______________________ The main role of NS is so-called "purifying selection"; i.e., getting rid of all those harmful mutations. And we know how NS works. By killing off the "unfit". So, how does that ONE beneficial mutation get anywhere when NS has to find some way of "killing off" the 99 harmful ones---meaning, of course, that the beneficial will, with all likelihood, suffer the same fate as the 99 bad ones. To give us a picture where, somewhere within a population, all these needed beneficial mutations are within the reach of organisms just when they need them, is to forget that the rule of genetics is stasis---the Hardy-Weinberg Equilibrium---and that the rule for NS is elimination of harmful mutations, and that the vast majority of mutations are either neutral of harmful. It's the 'rosy', but 'unrealistic' picture of population genetics that makes Darwinism seem "miraculous", as if it could really 'climb' Mt. Improbable.PaV_{June 24, 2011
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Because we can do the math? Apparently the answer to that question is no. Evolutionists are not so gullible because they can do the math. So why are they so gullible? Neil, surely you can answer the pop gen question about the probability that a mutation will be lost. The idea that advantageous mutations inexorably move to fixation is a myth.Mung_{June 24, 2011
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In the sense that they confer greater net reproductive advantage.
Well, why didn't you just say so. I mean it's not like I haven't been complaining for weeks now about how you keep shifting the way you speak about selection. When us normal folks think of an advantage, we think of the advantage one organism has over another. You know, as in, I can run farther, jump higher, and hold my breath longer than you. But that's not what you meant by it at all. What you mean was, I leave more offspring than you. Now how that's more advantageous to me, I don't know, especially if I have to support them all.Mung_{June 24, 2011
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Mung @ 13: Misssd this:
The degree of advantageousness? That’s a new one on me. As in some mutations are more advantageous than others? In what sense?
Mung, are you serious? Yes, some mutations are more advantageous than others. In the sense that they confer greater net reproductive advantage. This is absolutely core to Darwin's theory. Is it really new to you?Elizabeth Liddle_{June 24, 2011
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Taken from the article "My Criteria for Design" link below... The Eye Use: vision, of course. Location: Front of the face, and bilaterally is certainly the best location on the body for the eyeballs. Much better than under the arms or on the stomach. Individual shape: The ball shape allows for rotation in a socket so the eye can view in all directions. Common shape: The ball is the common shape of almost all vertebrate eyes. Owls are a rare exception. Assembly: The optic nerve, visual cortex, eyeballs, and code are all parts that need assembly and must have existed all together for functional vision. The list is, in reality, long, if we add in the lens, retina, iris, oculomotor muscles, nerve controllers for the iris, lens, .... Sub-function: The lens must be able to focus light that enters the eye, the retina must be able to take the image and pass it on to the optic nerve, .... Invention: At one time on the earth there was no vision, and no concept or notion of what vision might be. Copied by man: Digital cameras. Random natural occurrences: There has never been an instance when any man has shown that natural selection and friends can invent and construct a lens, an eyeball, much less a complete visual system. Complexity: What could be more complex than a complete visual system? http://evillusion.wordpress.com/40-my-criteria-for-design/melvinvines_{June 24, 2011
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Because we can do the math?
So first we need a mutation that is specific to the future formation of an eye. What is the probability of such a mutation? Next, what is the probability that the mutation will be lost, just due to chance?Mung_{June 24, 2011
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snelldl: Well, I just specified "an advantageous mutation", i.e. one that goes to fixation (or towards fixation) because it confers some reproductive advantage. That's the only criteria for "correctness" of the order, at least if we ignore the effects of drift (which we must not!). However, the advantage offered at the time may be unrelated to the final advantage. To take the eye: two stages postulated are: a photosensitive patch of surface that gives advance notice of a looming thing somewhere within 180 degrees; a depression in that surface that allows greater precision regarding direction. So you could argue that the depression is useless without the photosensitivity, so the photosensitivity comes first. However, the depression itself could be advantageous for some other reason, or may be a biproduct of some mutation that has some other advantageous phenotypic effect, or might simply be a neutral trait that has propagated by drift. So there's no reason to assume that one had to precede the other. Indeed, it's possible that both photosensitivity and skin depressions had quite different phenotypic advantages (perhaps the photosensitivity primarily gave notice of a heat source, originally), but when an individual inherited both together, the combination was very much more advantageous than either separately. Regarding your second point: this would be true of a very low dimensioned fitness landscape. But we know that fitness landscapes are very high-dimensioned - indeed we are talking about multiple dimensions here. For example there may be a local maximum regarding the degree to which a patch of skin can be tuned to sensitivity in a given part of the visible spectrum; but plenty of scope for improvement in the degree to which the patch is curved; and improvement along that dimension may itself offer for opportunities for selective tuning of different locations on the patch. Then there is protection of the patch by some translucent gene product; the degree to which that translucent body focuses the light; the mobility of the evolving eye, and the degree to which the organism can direct its gaze, etc. Once you have multiple dimensions, while there remain "traps" in the landscape, they are fairly rich traps. You may not be able to get from an octopus eye to a human eye and vice versa (or from a human lung to a bird lung), but that still leaves a lot of scope.Elizabeth Liddle_{June 24, 2011
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Dr Liddle: "...once you have an advantageous mutation, the number of opportunities for a second grow exponentially..." This seems like a serious oversimplification to me. Wouldn't this depend on whether the mutation was in the correct order of the correct sequence of the mutational path to the organ/function? A mutation may be at the peak of a local maximum, in which case there is zero chance for a second mutation to be advantageous.snelldl_{June 24, 2011
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I have serious eye trouble. i want healing of the eye to prevent blindness for me in the future as it is a option. As a YEC who sees a common blueprint to biology. This is how YEC explains the ape/man likeness. Not related but simply we have the best body given to us by God. All creatures are very alike and so we can only look a certain way to have dexterity. Therefore all eyes should be just a continium of the same blueprint for a mechanism to allow seeing. Therefore by studying the eyes of all creatures one could discover the true equations that are what the eye is about. Then heal it. It suits me that all eyes are just using the same principals or laws to give sight to its host. not evolutionary stages but simply more atomic stages of the single mechanism. God didn't make a eye but a bigger equation of sight which components can be broken down depending on need. A higher law of biology.Robert Byers_{June 24, 2011
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You're a funny guy Neil. And I do mean funny haha. I have to give you credit for really doing your homework on this one.
Recently, Scientific American came out with an article on the history of the evolution of the eye. Intelligent Design proponents have used that as the basis for renewing old creationist arguments against the idea that the eye evolved. See here and here.
So now we're using the Scientific American article as the basis for "renewing old creationist arguments against the idea that the eye evolved." And to prove this you cite two sources. Your first source is the ENV article linked to in the OP. And your second source is the OP, which consists mainly of a short comment and a link to the ENV article! Brilliant sleuthing!Mung_{June 23, 2011
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"Why are evolutionists so gullible?" Because if they weren't, Dawkins (the Pope of atheism) would chide them for their personal incredulity.Ilion_{June 23, 2011
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NOPEMung_{June 23, 2011
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oh, wait. You're engaging in that same tactic, aren't you!
The Scientific American article is about the evolution of the physical eye, rather than about the evolution of the visual system. The ID response, too, is about the physical eye. But it is the usual argument about irreducible complexity.
ok, well. Since you don't quote anyone, now I get to follow the two links you posted where I will surely find the claim that the physical eye is irreducibly complex.Mung_{June 23, 2011
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Oh, for the record, no I do not believe the eye to be irreducibly complex.
For the record, does anyone here think the eye is irreducibly complex? Or is that just yet another straw man set up by people like Lamb because they lack any real scientific evidence?Mung_{June 23, 2011
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I have posted some thoughts on the evolution of vision at my own blog. They are not a direct response to the opening post of this thread, but they related to the issue of whether the eye is irreducibly complex. Oh, for the record, no I do not believe the eye to be irreducibly complex.Neil Rickert_{June 23, 2011
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Eye Evolution-It's Impossible: (parts 1,2 & 3) http://www.youtube.com/watch?v=rRDAY39Zd9M http://www.youtube.com/watch?v=W9KQecDfn_o http://www.youtube.com/watch?v=LTYO0GLTkB4melvinvines_{June 23, 2011
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this is very similar to the supposed evolution of the sexes...it sho was clever of evolution to evolve male and female at the same time... and bacteria does quite well without sight...but of course stuff happens for the darwinists...evolution makes giraffes tall and pygmys small...evolution is all in all..praise darwin!tsmith_{June 23, 2011
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this just shows that evolution is nothing more than atheist faith (with racism and eugenics built in of course). the darwinists cannot list the mutations that led to the eye...yet they have no doubts the eye evolved...it had to, the alternative is UNTHINKABLE to them. of course the pax6 gene being at the heart of all the designed of eyes clearly indicates design...but the darwinists never let facts get in the way of their faith.tsmith_{June 23, 2011
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mike1962 said: "Either you can do it or you can’t." === Never underestimate the power of FAITH Mike, no matter whose religion it is.Eocene_{June 23, 2011
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Elizabeth Liddle: As we say in the engineering racket (because we have to - who would fly on our planes if we didnt?), why don't you prove your concept? Given what we know about biological systems, show us a pathway where a vast number of small mutations can lead to an eye. Either you can do it or you can't.mike1962_{June 23, 2011
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Mung: How long did it take for each mutation to become fixed in the population? Depends on the degree of advantageousness.
The degree of advantageousness? That's a new one on me. As in some mutations are more advantageous than others? In what sense?Mung_{June 23, 2011
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Elizabeth Liddle:
...once you have an advantageous mutation, the number of opportunities for a second grow exponentially.
Except the eye is composed of numerous systems of proteins; it is not even enough to get them all at the same time in the same place; they have to be created and used at the right times in the right places. There is no mount-improbable path that leads from sightlessness to sight, any more than, by rearranging the words, letters, paragraphs (Insert lexical component or operation here) you can get from instructions for something brand new from instructions for an existing item. Valid, functioning biological solutions are not situated in "function space" in any manner amenable to traverse by single or double mutations. The only beneficial mutations ever found are extremely simple; the overwhelming majority are neutral or destructive, and even ones that are beneficial are nearly always sabotaging some non-critical function that became vulnerable. Saying "you just need a few (or a thousand) beneficial mutations to make an eye" is like saying you just need a few beneficial tornados to make 747s.SCheesman_{June 23, 2011
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Elizabeth:
However, my more serious point is that there is a tendency, in my experience, for people who regard the evolution of the eye as extremely improbable to forget that once you have an advantageous mutation, the number of opportunities for a second grow exponentially.
The number of opportunities for a second eye? That explains it! Or random mutations aren't really random? So in your view mutations are not independent events? So once a beneficial mutation takes place, it increases the probability that yet another beneficial mutation will take place in the same lineage? Or does the first beneficial mutation have to move to fixation first? What about the rest of the population. Does a beneficial mutation in one member increase the likelihood that other members in that same population who lack that mutation will get the same or a different beneficial mutation? Are these figures published? Is there any way your claim can be put to the test? Is it science, or is it science fiction?Mung_{June 23, 2011
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Because we can do the math?
Elizabeth Liddle, is that your program? Have you come here to make claim after claim of what you can do, only to deliver nothing but polite conversation? You already have a project to complete, do you not? Where is the draft of the simulation you've promised?Upright BiPed_{June 23, 2011
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