"New eye discovery further demolishes Dawkins"

"Backwardly wired retina an optimal structure"

Incl. intelligent design, belief in divine creation

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Re: "New eye discovery further demolishes Dawkins"

#301  Postby DavidMcC » Jun 23, 2014 11:33 am

halucigenia wrote:
DavidMcC wrote:Sorry to be such a purist, and refer to the OP topic, but something was left unsaid throughout this thread (mainly because I did not look at it for a long time):
Dawkins misunderstood vertebrate eye biology for a long time, and that made him vulnerable to criticisms along the lines of the OP linked creationist article. He had not understood that the selective traits of the vertebrate eye were very different from those of the cephalopod eye, cause the latter was based on maximum sensitivity to light sacrificing maintainability, whereas the former sacrificed some sensitivity, but achieved a much greater useful life in daylight, making it possible for some vertebrates to be sometimes much longer lived, and hence bigger, stronger, cleverer than most invertebrates, who are compromised by the "design" weakness of their retinae from that POV.

EDIT: A key cell type in the vertebrate eye is the retinal pigment epithelial cell. This is the real work-horse of retinal maintenance, as one of its key functions is the daily recycling of the hindmost opsin discs in its associated photoreceptor cell.


DavidMcC wrote:... The evolutionary biologist who pioneered work that showed that the hagfish is a protovertebrate was Trevor Lamb, working in collaboration with Pugh and others. The main point here being that hagfish eyes are non-imaging, but already have a large retina, and a convex exterior.
EDIT: These features were both for efficient light-gathering in a very low light enviroment (scotopic).
My theory goes that, when some ancient hagfish-like animals were forced by geological upheavals into shallow, photopic seas, they rapidly evolved imaging vision from those simple eyes, because the shallow seas were a battleground, full of sighted invertebrates at the time.

Kind of arguing against yourself there aren't you? :doh:

Not at all. Please explain why you think that.
EDIT: Oh, I think I see what your misunderstanding is: The point is that hagfish "eyes" are adapted to non-imaging vision in very low light levels. By the time the population of hagfishes that were forced to shallow waters had adapted to that, they were not hagfish any more. Modern descendants of such animals would be at least some of the lampreys, which have an almost vertebrate type of eye.

DavidMcC wrote:Dawkins, who had an inadequate model of vertebrate eye evolution - he saw it as being mollusc eyes plus one extra step to turn the retinae inside out!
Citation required. :snooty:

It's in at least one of his famous (and generally excellent, apart from the eye biology) books on evolution for the layman.
I haven't got the exact book/page reference, but I well remember a sequence of diagrams illustrating the stages of the "evolution of the eye", in which all but the final one referred to one species or other of mollusc, but the final one was the human eye! The large internal differences between the last two, in terms of retinal structure, were played down by using vague diagrams. The unspoken implication was that vertebrate eyes were just the final stage of mollusc eye evolution!
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Re: "New eye discovery further demolishes Dawkins"

#302  Postby halucigenia » Jun 23, 2014 12:50 pm

DavidMcC wrote:
halucigenia wrote:
DavidMcC wrote:He had not understood that the selective traits of the vertebrate eye were very different from those of the cephalopod eye, cause the latter was based on maximum sensitivity to light


DavidMcC wrote:These features [large retina, and a convex exterior in hagfish] were both for efficient light-gathering in a very low light enviroment (scotopic).

Kind of arguing against yourself there aren't you? :doh:

Not at all. Please explain why you think that.
The highlighted bits seem to be saying that you think that both types of eye evolved in response to light sensitivity/efficient light-gathering. Rather than arguing a valid reason why they are different you seem to be arguing that they are different for the same reason.
DavidMcC wrote:EDIT: Oh, I think I see what your misunderstanding is: The point is that hagfish "eyes" are adapted to non-imaging vision in very low light levels. By the time the population of hagfishes that were forced to shallow waters had adapted to that, they were not hagfish any more. Modern descendants of such animals would be at least some of the lampreys, which have an almost vertebrate type of eye.
However above this you stated that the cephalopod eye was based on maximum sensitivity to light, presumably in low light levels too, so they both evolved as non imaging eyes adapted to light sensitivity under low light levels, and it is not relevant where/how the later imaging/maintenance mechanisms evolved, no?
The fact that the eye structure of the vertebrate and the mollusc happened to start out as non imaging eyes of different structure regarding whether the nerve fibres are in front or behind the retina is the relevant point, not how or what other mechanisms they then evolved. Obviously the inverted and non inverted retina evolved differently and had the propensity to evolve different repair mechanisms etc. I simply cannot see how your argument, which appears to contradict itself, in any way backs up your claims regarding Dawkins “bad design” argument.
DavidMcC wrote:
halucigenia wrote:
DavidMcC wrote:Dawkins, who had an inadequate model of vertebrate eye evolution - he saw it as being mollusc eyes plus one extra step to turn the retinae inside out!
Citation required. :snooty:

It's in at least one of his famous (and generally excellent, apart from the eye biology) books on evolution for the layman.
I haven't got the exact book/page reference, but I well remember a sequence of diagrams illustrating the stages of the "evolution of the eye", in which all but the final one referred to one species or other of mollusc, but the final one was the human eye! The large internal differences between the last two, in terms of retinal structure, were played down by using vague diagrams. The unspoken implication was that vertebrate eyes were just the final stage of mollusc eye evolution!
Well you had better come up with that reference because your “unspoken” implication is totally unsupported unless we can all see the figure and explanatory text for ourselves. Most likely Dawkins was just using different types of eyes from different extant organisms to show the general stages through which eye evolution could have taken place and never even “unspokenly” implied that there was “one extra step to turn the retinae inside out”. I am sure that Dawkins knows fine well that vertebrate eyes did not develop from mollusc eyes or the retinae ever had to turn inside out in the way in which you assert him to, but started out that way in the in the vertebrate lineage. I suspect that your position is simply a strawman argument. As I said, a citation for this absurd claim is required.
Edit: fixed quote tags
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Re: "New eye discovery further demolishes Dawkins"

#303  Postby DavidMcC » Jun 23, 2014 1:25 pm

halucigenia wrote:
DavidMcC wrote:
halucigenia wrote:
DavidMcC wrote:He had not understood that the selective traits of the vertebrate eye were very different from those of the cephalopod eye, cause the latter was based on maximum sensitivity to light


DavidMcC wrote:These features [large retina, and a convex exterior in hagfish] were both for efficient light-gathering in a very low light enviroment (scotopic).

Kind of arguing against yourself there aren't you? :doh:

Not at all. Please explain why you think that.
The highlighted bits seem to be saying that you think that both types of eye evolved in response to light sensitivity/efficient light-gathering. Rather than arguing a valid reason why they are different you seem to be arguing that they are different for the same reason.
DavidMcC wrote:EDIT: Oh, I think I see what your misunderstanding is: The point is that hagfish "eyes" are adapted to non-imaging vision in very low light levels. By the time the population of hagfishes that were forced to shallow waters had adapted to that, they were not hagfish any more. Modern descendants of such animals would be at least some of the lampreys, which have an almost vertebrate type of eye.
However above this you stated that the cephalopod eye was based on maximum sensitivity to light, presumably in low light levels too, so they both evolved as non imaging eyes adapted to light sensitivity under low light levels, and it is not relevant where/how the later imaging/maintenance mechanisms evolved, no?
No. What I neglected to menton this tine around is that cephalopod eyes evolved in the photopic shallow seas, but were none-the-less competing for sensitivity.
The fact that the eye structure of the vertebrate and the mollusc happened to start out as non imaging eyes of different structure regarding whether the nerve fibres are in front or behind the retina is the relevant point, not how or what other mechanisms they then evolved. Obviously the inverted and non inverted retina evolved differently and had the propensity to evolve different repair mechanisms etc. I simply cannot see how your argument, which appears to contradict itself, in any way backs up your claims regarding Dawkins “bad design” argument.

My point is that cephalopod eyes cannot protect the opsins in their photoreceptors against photo-chemical damage by light. The vertebrate eye can, exploiting the fact that the photoreceptors can be maintained by the RPE cells, with their rich blood supply from the choroid layer. The choroid layer is only possible because of the "inverted" structure of the retina.
DavidMcC wrote:
halucigenia wrote:
DavidMcC wrote:Dawkins, who had an inadequate model of vertebrate eye evolution - he saw it as being mollusc eyes plus one extra step to turn the retinae inside out!
Citation required. :snooty:

It's in at least one of his famous (and generally excellent, apart from the eye biology) books on evolution for the layman.
I haven't got the exact book/page reference, but I well remember a sequence of diagrams illustrating the stages of the "evolution of the eye", in which all but the final one referred to one species or other of mollusc, but the final one was the human eye! The large internal differences between the last two, in terms of retinal structure, were played down by using vague diagrams. The unspoken implication was that vertebrate eyes were just the final stage of mollusc eye evolution!
Well you had better come up with that reference because your “unspoken” implication is totally unsupported unless we can all see the figure and explanatory text for ourselves. Most likely Dawkins was just using different types of eyes from different extant organisms to show the general stages through which eye evolution could have taken place and never even “unspokenly” implied that there was “one extra step to turn the retinae inside out”. I am sure that Dawkins knows fine well that vertebrate eyes did not develop from mollusc eyes or the retinae ever had to turn inside out in the way in which you assert him to, but started out that way in the in the vertebrate lineage. I suspect that your position is simply a strawman argument. As I said, a citation for this absurd claim is required.
Edit: fixed quote tags

It is not a strawman. I now have a page reference for the bad biology:
"Climbing Mount Improbable", chapter 5, page 153, Fig,5.14 from Nilsson and Pelger.
The reader is left to assume that the "fish" referred to in the fish-eye sequence is a vertebrate fish, because othing to the contrary is mentioned in the text. The sequence I have referenced is not the only one I know of, but it is the only one that I can find at the moment.
I accept that RD was not the instigator of this mistake, but he certainly propagated it, aided and abetted, it seems, by an aquaintance of his, who works for Nikon!
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Re: "New eye discovery further demolishes Dawkins"

#304  Postby DavidMcC » Jun 23, 2014 1:36 pm

halucigenia wrote:
DavidMcC wrote:
halucigenia wrote:
DavidMcC wrote:He had not understood that the selective traits of the vertebrate eye were very different from those of the cephalopod eye, cause the latter was based on maximum sensitivity to light


DavidMcC wrote:These features [large retina, and a convex exterior in hagfish] were both for efficient light-gathering in a very low light enviroment (scotopic).

Kind of arguing against yourself there aren't you? :doh:

Not at all. Please explain why you think that.
The highlighted bits seem to be saying that you think that both types of eye evolved in response to light sensitivity/efficient light-gathering. Rather than arguing a valid reason why they are different you seem to be arguing that they are different for the same reason.
DavidMcC wrote:EDIT: Oh, I think I see what your misunderstanding is: The point is that hagfish "eyes" are adapted to non-imaging vision in very low light levels. By the time the population of hagfishes that were forced to shallow waters had adapted to that, they were not hagfish any more. Modern descendants of such animals would be at least some of the lampreys, which have an almost vertebrate type of eye.
However above this you stated that the cephalopod eye was based on maximum sensitivity to light, presumably in low light levels too, so they both evolved as non imaging eyes adapted to light sensitivity under low light levels, and it is not relevant where/how the later imaging/maintenance mechanisms evolved, no?
The fact that the eye structure of the vertebrate and the mollusc happened to start out as non imaging eyes of different structure regarding whether the nerve fibres are in front or behind the retina is the relevant point, not how or what other mechanisms they then evolved. Obviously the inverted and non inverted retina evolved differently and had the propensity to evolve different repair mechanisms etc. I simply cannot see how your argument, which appears to contradict itself, in any way backs up your claims regarding Dawkins “bad design” argument.
DavidMcC wrote:
halucigenia wrote:
DavidMcC wrote:Dawkins, who had an inadequate model of vertebrate eye evolution - he saw it as being mollusc eyes plus one extra step to turn the retinae inside out!
Citation required. :snooty:

It's in at least one of his famous (and generally excellent, apart from the eye biology) books on evolution for the layman.
I haven't got the exact book/page reference, but I well remember a sequence of diagrams illustrating the stages of the "evolution of the eye", in which all but the final one referred to one species or other of mollusc, but the final one was the human eye! The large internal differences between the last two, in terms of retinal structure, were played down by using vague diagrams. The unspoken implication was that vertebrate eyes were just the final stage of mollusc eye evolution!
Well you had better come up with that reference because your “unspoken” implication is totally unsupported unless we can all see the figure and explanatory text for ourselves. Most likely Dawkins was just using different types of eyes from different extant organisms to show the general stages through which eye evolution could have taken place and never even “unspokenly” implied that there was “one extra step to turn the retinae inside out”. I am sure that Dawkins knows fine well that vertebrate eyes did not develop from mollusc eyes or the retinae ever had to turn inside out in the way in which you assert him to, but started out that way in the in the vertebrate lineage. I suspect that your position is simply a strawman argument. As I said, a citation for this absurd claim is required.
Edit: fixed quote tags

It is not an absurd claim. Dawkins genuinely thought that the vertebrates' inverted retina, with the ganglion nerve fibres running across the retina, over the photoreceptor layer, was "bad design", rather than a good trade-off, sacrificing some sensitivity to light (occurring AFTER the hagfish phase) for better maintainability against photo-chemical damage to opsins.

EDIT: To be fair to RD, he was not the only one to fail to appreciate the effect of photo-oxidative damage to opsins on vertebrate eye evolution.
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Re: "New eye discovery further demolishes Dawkins"

#305  Postby Animavore » Jun 23, 2014 1:48 pm

DavidMcC wrote:
It is not a strawman. I now have a page reference for the bad biology:
"Climbing Mount Improbable", chapter 5, page 153, Fig,5.14 from Nilsson and Pelger.
The reader is left to assume that the "fish" referred to in the fish-eye sequence is a vertebrate fish, because othing to the contrary is mentioned in the text. The sequence I have referenced is not the only one I know of, but it is the only one that I can find at the moment.
I accept that RD was not the instigator of this mistake, but he certainly propagated it, aided and abetted, it seems, by an aquaintance of his, who works for Nikon!


Looking at the diagram now.

What's the problem? It's a computer model based mathematical principles and allowed to 'evolve' on it's own in a simulation with eyes being selected for which have a 1% change in magnitude of one of its properties to go forward to the next 'generation'. The steps shown are taken after every few 'generations'. It states this clearly.
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Re: "New eye discovery further demolishes Dawkins"

#306  Postby DavidMcC » Jun 23, 2014 1:55 pm

Animavore wrote:
DavidMcC wrote:
It is not a strawman. I now have a page reference for the bad biology:
"Climbing Mount Improbable", chapter 5, page 153, Fig,5.14 from Nilsson and Pelger.
The reader is left to assume that the "fish" referred to in the fish-eye sequence is a vertebrate fish, because othing to the contrary is mentioned in the text. The sequence I have referenced is not the only one I know of, but it is the only one that I can find at the moment.
I accept that RD was not the instigator of this mistake, but he certainly propagated it, aided and abetted, it seems, by an aquaintance of his, who works for Nikon!


Looking at the diagram now.

What's the problem? It's a computer model based mathematical principles and allowed to 'evolve' on it's own in a simulation with eyes being selected for which have a 1% change in magnitude of one of its properties to go forward to the next 'generation'. The steps shown are taken after every few 'generations'. It states this clearly.

OK. That makes it somewhat abstract, but his known position on vertebrate retinae is that they are "badly designed", because they don't match the predictions of the simple computer model, or those of the "well designed" cephalopod eyes.
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Re: "New eye discovery further demolishes Dawkins"

#307  Postby Animavore » Jun 23, 2014 1:59 pm

untitled.JPG
untitled.JPG (45.96 KiB) Viewed 28395 times


Diagram in question. It's a theoretical evolutionary model which the computer came across all by itself just by giving it a starting point and entering simple parameters for 'improvement'.

From the text on that page.

However we choose to run our model, whether in ‘natural-selection mode’ or in ‘systematic exploration of the mountain mode’, we have to decide upon some rules of embryology: that is, some rules governing how genes control the development of bodies. What aspects of shape do the mutations actually operate upon? And how big, or how small, are the mutations themselves? In the case of NetSpinner, the mutations act upon known aspects of the behaviour of spiders. In the case of biomorphs, mutations act upon the lengths and angles of branches in growing trees. In the case of eyes, Nilsson and Pelger began {162} by acknowledging that there are three main types of tissue in a typical ‘camera’ eye. There is an outer casing to the camera, usually opaque to light. There is a layer of light-sensitive ‘photocells’. And there is some kind of transparent material, which may serve as a protective window or which may fill the cavity inside the cup — if, indeed, there is a cup, for we are not taking anything for granted in our simulation. Nilsson and Pelger's starting point — the foot of the mountain — is a flat layer of photocells (grey in Figure 5.14), sitting on a flat backing screen (black) and topped by a flat layer of transparent tissue (off-white). They assumed that mutation works by causing a small percentage change in the size of something, for example a small percentage decrease in the thickness of the transparent layer, or a small percentage increase in the refractive index of a local region of the transparent layer. Their question really is, where can you get to on the mountain if you start from a given base camp and go steadily upwards? Going upwards means mutating, one small step at a time, and only accepting mutations that improve optical performance.

So, where do we get to? Pleasingly, through a smooth upward pathway, starting from no proper eye at all, we reach a familiar fish eye, complete with lens. The lens is not uniform like an ordinary man-made lens. It is a graded index lens such as we met in Figure 5.13b. Its continuously varying refractive index is represented in the diagram by varying shades of grey. The lens has ‘condensed’ out of the vitreous mass by gradual, point by point changes in the refractive index. There is no sleight of hand here. Nilsson and Pelger didn't pre-pro-gram their simulated vitreous mass with a primordial lens just waiting to burst forth. They simply allowed the refractive index of each small bit of transparent material to vary under genetic control. Every smidgen of transparent material was free to vary its refractive index in any direction at random. An infinite number of patterns of varying refractive index could have emerged within the vitreous mass. What made the lens come out lens-shaped’ was unbroken upward mobility, the equivalent of selectively breeding from the best seeing eye in each generation.
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Re: "New eye discovery further demolishes Dawkins"

#308  Postby DavidMcC » Jun 23, 2014 2:04 pm

Yes, but he also thought that that was how the vertebrate eye should look, if it was "well designed", like a cephalopod eye.
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Re: "New eye discovery further demolishes Dawkins"

#309  Postby Animavore » Jun 23, 2014 2:05 pm

DavidMcC wrote:Yes, but he also thought that that was how the vertebrate eye should look, if it was "well designed", like a cephalopod eye.


No he didn't. That is not the point he was trying to make at all.
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Re: "New eye discovery further demolishes Dawkins"

#310  Postby DavidMcC » Jun 23, 2014 2:20 pm

You can kid yourself, maybe, but I have found another old reference, this time in "The Greatest Show on Earth", chapter 11, "History written all over us", p354:
"But now, suppose I tell you that the eye's 'photocells' are pointing backwards, away rom the scene being looked at. The wires connecting the photocells to the brain run all over the surface of the retina... That doesn't make sense...". (My bold) His problem might be that Nikon don't make self-maintaining CCD arrays, so his technical advice was bad from the start. (He quoted his Nikon friend at some point, on camera design.)
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Re: "New eye discovery further demolishes Dawkins"

#311  Postby Oldskeptic » Jun 23, 2014 7:44 pm

DavidMcC wrote:You can kid yourself, maybe, but I have found another old reference, this time in "The Greatest Show on Earth", chapter 11, "History written all over us", p354:
"But now, suppose I tell you that the eye's 'photocells' are pointing backwards, away rom the scene being looked at. The wires connecting the photocells to the brain run all over the surface of the retina... That doesn't make sense...". (My bold) His problem might be that Nikon don't make self-maintaining CCD arrays, so his technical advice was bad from the start. (He quoted his Nikon friend at some point, on camera design.)


There is no problem with Dawkins' argument because it is not an argument for evolution of the eye, that's already a given. Nor is it an argument against a creator/designer, it's an argument against an intelligent creator/designer. And he's not arguing that the eye as it is now isn't excellent at what it does. The argument is that an intelligent designer wouldn't have had to put in as many patches and fixes to make it excellent. If designed properly and intelligently it wouldn't need to be as complicated as it is.

All the arguments in the original post article are for how well the eye works now, which is something that Dawkins never argued against, so it's rather pointless, and amounts to little more than agreeing with Dawkins and then crowing about how right they are in the end.

The main argument in the article is that the backward wiring is required for regenerating photoreceptors after a flash or bright light, but misses the point that if intelligently designed that too could have been done better, making all the fixes and patches unnecessary. A good design is one that accomplishes the goal in the simplest way possible, and the eye is not an example of this.

Let's look at this from the stand point of a good intelligent designer. If the design was set, was simple, and achieved the goal, but with one problem. Do you think that a good intelligent designer would scrap the whole design, turn it backwards and rewire the whole thing, then make other hardware and software fixes to accommodate the new complicated design? I don't. I think that a good intelligent designer would find one fix for the one problem and maintain the simple effective design.
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Re: "New eye discovery further demolishes Dawkins"

#312  Postby Calilasseia » Jun 23, 2014 10:07 pm

The only "intelligent" designer I know of that would do this, would be one being paid a huge sum of money to do it by an extremely rich committee. :mrgreen:
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Re: "New eye discovery further demolishes Dawkins"

#313  Postby Calilasseia » Jun 23, 2014 10:20 pm

Meanwhile, a thought has just crossed my mind.

The idea that photo-oxidative damage to opsins could be a factor here, omits one key feature. Namely, that opsins are replaced over time. We don't just start off with one collection of opsin molecules, which have to serve us for the rest of our lives. Replacement opsins are manufactured metabolically. Otherwise, why would Vitamin A be an essential part of our diet?

Plus, vertebrate opsins are different from those of invertebrates. According to here, vertebrates use Go and Gs family opsins, whilst arthropods and molluscs (including cephalopods) use Gq family opsins.

Furthermore, according to this page on the Visual Cycle, recharging of "spent" opsins is performed by at least one reducingenzyme. Which would seem to be a factor mitigating against oxidative damage, if the same reducing process is found in organisms other than vertebrates. Metabolic replacement of opsins damaged oxidatively in ways unrecoverable by those enzymes would solve the problem in any case.

EDIT: A far more comprehensive treatment can be found here, a page devoted to comprehensive physiology and molecular biology of the eye.
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Re: "New eye discovery further demolishes Dawkins"

#314  Postby halucigenia » Jun 24, 2014 2:03 am

DavidMcC wrote:
It is not a strawman. I now have a page reference for the bad biology:
"Climbing Mount Improbable", chapter 5, page 153, Fig,5.14 from Nilsson and Pelger.
The reader is left to assume that the "fish" referred to in the fish-eye sequence is a vertebrate fish, because othing to the contrary is mentioned in the text. The sequence I have referenced is not the only one I know of, but it is the only one that I can find at the moment.
I accept that RD was not the instigator of this mistake, but he certainly propagated it, aided and abetted, it seems, by an aquaintance of his, who works for Nikon!
Well, there's no reference there to the backwards retina, nor to molusk eyes at all, never mind “one extra step to turn the retinae inside out”.
Come on, admit it, you were making this up all along. :nono:

DavidMcC wrote:You can kid yourself, maybe, but I have found another old reference, this time in "The Greatest Show on Earth", chapter 11, "History written all over us", p354:
"But now, suppose I tell you that the eye's 'photocells' are pointing backwards, away rom the scene being looked at. The wires connecting the photocells to the brain run all over the surface of the retina... That doesn't make sense...". (My bold) His problem might be that Nikon don't make self-maintaining CCD arrays, so his technical advice was bad from the start. (He quoted his Nikon friend at some point, on camera design.)
Quite, as I thought, this is a separate claim from the sequence of possible steps to form a modern vertebrate or cephalopod eye. It is a claim that the initial arrangement "...The wires connecting the photocells to the brain run all over the surface of the retina... That doesn't make sense..." rather than anything about its subsequent evolution to form a "camera" type eye which then had to take “one extra step to turn the retinae inside out”.
His point, and the title of the chapter "History written all over us" confirms this, is that it is historical happenstance that the structure of the eye in vertebrates happened to be the way that it is in respect of the inverted retina and that it became the way that it currently is with respect to its current functionality simply because of this, rather than because of the foresight of an intelligent designer.
Even if Nikon did decide to make self-maintaining CCD arrays, without referencing vertebrate eye structure, do you think that they would have started off with a CCD array "pointing backwards" and build from there, or do you think that at some point they would even take the step to turn the array the other way around and re-design from there as you have suggested that Dawkins thought happened in the evolution of the vertebrate eye? Are you suggesting that this would be "good/intelligent" design practice? :ask:

Building a self repairing CCD array that requires software to ignore the wiring running all over the surface and the point at which all the wiring all goes through the array at one position might make it possible but it would still seem like a kludge to me. :dunno:
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Re: "New eye discovery further demolishes Dawkins"

#315  Postby Jayjay4547 » Jun 24, 2014 8:07 am

Oldskeptic wrote:

Brain does attribute jaw bones at Swartkrans to leopards, but he is wrong. What they are is jaw bones of ancestors of leopards. Leopards had not evolved yet, and what left those jaw bones was no a more a leopard than the bones left by Australopithecus were human.


You don’t say where you get the information to contradict Dr Brain. The Wiki entry on leopards cite Uphyrkina et al(2001) to support the origin of modern leopard lineages 470000-825000 years ago. http://www.biosoil.ru/files/00001386.pdf

That study is based on worldwide genetic differences between living leopards assuming constant-rate genetic changes. The rate of change was calibrated from Turner and Anton (1997) report of leopard and lion fossils from Laetoli, 3.5ma. So it was adopted that lion and leopard lineages diverged at that date. From this calibration, the date of first divergence of living leopards was estimated to be up to 0.825 ma. Please note, Turner reported “leopard” not “ancestral leopard”. Indeed it’s quite tricky to declare some species as ancestral to another, it can easily turn out that that the branch point was earlier. There is no support for your claim that there were no leopards in the days of Australopithecus.

Oldskeptic wrote:
The tooth marks on the skull, if that's what they are and not just a coincidence, is not evidence that the cat killed the Australopithecus, at best it is evidence that the cat may have dragged a dead Australopithecus into the cave by the head. Did the cat kill or scavenge? We don't know.


Just coincidence? The match was a noteworthy discovery. It wasn’t achieved by a random computer search. Here’s the scenario. Bob notices dents on the Kranskop skull. My word thinks Bob. Could these be marks from a leopard’s teeth? He goes along the shelves containing 250 000 fossils from the Kranskop site till he finds the mandible. And gosh, it’s a perfect fit. Of course it could be coincidental, but it’s noteworthy and the ability to note is one of the things that has made Brain a scientist’s scientist; with honorary doctorates from four top universities in his country, in addition to his two professional doctorates.

Yes, it’s possible the Kranskop individual died from natural causes and the leopard just dragged it into the cave.
Oldskeptic wrote:
Saber-toothed cats most likely preyed on large slow herbivores, and were not well suited for catching smaller prey. This is where the evidence leads.


It’s almost incredible that you can say “That’s where the evidence leads” just after you have noted the possibility that the Kranskop leopard just dragged in a scavenged carcass. Well yes it’s also possible that the eagle that put its talons through the eyes of the Taung child had scavenged that.

There has been speculation that the sabretooth was a specialized hominin hunter, using its big teeth to make a quick kill and get away before the troop could concentrate. It may be though that once a habituated cat could get its teeth into a primate it could make a quick kill anyway. Boesch (1991) reports a leopard crushing a chimp’s rib cage
http://www.eva.mpg.de/primat/staff/boes ... dation.pdf

Even if the sabretooth was not an intentional hunter of australopiths it could have denied them foraging space the same way a Abram tank stops bickering between fighters armed with AK47s. It’s unlikely sabretooths were a negligible factor .

Oldskeptic wrote:
The ancestral hyenas of the time were not well suited for catching prey at all. With their strong heavy jaws they were very well suited to scavenge the carcasses of the large prey left behind by saber-toothed cats. This is where the evidence leads.


The evidence leading you seems to be the merest conventional knowledge of hyena. In this National geographic feature, http://ngm.nationalgeographic.com/ngm/0506/feature3/
hyenas are shown to be proficient hunters [i]Hyenas have an undeserved reputation as thieves and scavengers that subsist on the leavings of the larger predator. "But it is far more frequent that the lion will steal a kill from the hyenas," says Kay Holekamp of Michigan State University.

Oldskeptic wrote:
I'm making no assumptions here that Australopithecus wasn't prey to some predator or that it was. It could be either way or somewhere in the middle. We don't know.

Just as we don't know how much time Australopithecus might have spent in the trees or on the ground we don't know if any of the big cats of the time were adept at climbing trees.


You can’t discount Brain’s paleontological evidence that leopards lived with and probably preyed on the robust australopiths- or Paranthropus. Leopards are highly adept at tree climbing- as are felids generally, excepting ground-adapted lion and cheetah. Australopith feet were not adapted to grasping branches. We have tracks of them walking on the ground:

Image

What we can know about the australopiths is that like all species in Africa they faced multiple predation threats and had a set of rules for responding to each. The degree of threat depended fluidly on circumstance; as with baboons, they could sometimes ignore a particular predator, in other circumstances it would prove fatal. They were under adaptive pressure to be able to forage in places as suited them, at times that suited them, in numbers that suited them, in all seasons and in all contexts of availability of alternative prey species.

Oldskeptic wrote:
How about admit that you don't have enough information to build a model. Never mind that there were no leopards at the time, and what saber-toothed cats there were preyed on large slow herbivores, and the ancestors of modern hyenas at the time had jaws suitable for bone crushing and scavenged what the saber-toothed cats left behind.


I’m not obliged to admit your jury-rig. Whether it’s a fossil australopith, T. rex or an algal mat, as soon as you see the fossil you can start to build a picture of its relation with its environment and it’s natural to do that. With the australopiths you start with a recognition that they lived in the larder of a cohort of proficient predators who had also alternative prey- and the alternative prey were proficient at avoiding predation. That’s the essential context and your blindness to it is astonishing, it requires an explanation. My explanation involves the influence of atheist ideology.

Oldskeptic wrote:
JayJay wrote:
There were leopards, and you are taking a simplistic view of hyena. In this study of predation on livestock in Tanzania Kissui(2008) “A total of 396 attack events were reported on cattle, goats/sheep, donkeys and dogs during the 19-month study period: 58% (n= 231) were by hyenas, 25% (n= 99) by lions and 17% (n= 66) by leopards.

http://www.cbs.umn.edu/sites/default/fi ... ersion.pdf


I'm just using what I've read about leopards and hyena ancestors, and not simplifying anything.

Tell me what modern African predators and livestock they kill and how they are killed as retaliation has anything to do with what is being discussed.


The modern context is a usable proxy for the African context a couple of million years ago. The link above demonstrates that hyenas are active predators, not just scavengers.

Oldskeptic wrote:
JayJay wrote:
The hidden contrary assumption you are making is the australopiths didn’t have any significant predators. Uniquely in their biome, they paid no forfeit in biomass to the top of the trophic pyramid, they could go anywhere at any time of their choice in any array as suited them without fear of predation. None of that is reasonable.


I didn't make any assumption. I said we don't know, and that is not an assumption.


You are doing a very interesting thing, which is choosing to not picture the australopiths at all, and calling that not making any assumption.
Oldskeptic wrote:
JayJay wrote:
I certainly don’t admit that[that I simply don't know if they even used weapons]. It’s a strong inference that the australopiths used hand-held weapons against predation, maybe as strong as the inference originally made of T. rex, that it was a meat eater.


Of course you don't admit it because you want to make inferences and assumptions based on nothing but your wishful thinking.


Make up your mind. You say I admit, then that “of course” I don’t admit. Get it straight. I don’t admit
Oldskeptic wrote:
JayJay wrote:
From the inference one can predict that these weapons will be found, taphonomy permitting.


See, no weapons found, but you still want to assume that they were used.

Nope, no weapons found, just the fossil of the body that used the weapons. Just like, when the first T. rex was found, it was inferred from its body that it ate meat.
Oldskeptic wrote:
JayJay wrote:
The inference is drawn (again) from the australopiths eye teeth being unsuitable for tearing in conjunction with the use of the arms, from general primate use of biting, from lack of branch-grasping by their hind feet, their apparent lack of sprinting ability and from their descendant’s known use of hand weapons against predation.


Inference drawn from more baseless assumptions. Who says that australopiths couldn't climb trees or weren't fast sprinters? Some evidence suggests otherwise. That they were well suited for walking on tree branches and walking and running on land.


I’m sure australopiths could climb trees and did climb them to escape from some predators some of the time. And to get away from irritable buffalo etc. But their feet were not adapted, as tree-adept primates are, for grasping branches, which is useful for avoiding predation by adept climbing predators. Darwin recognised this difference by calling apes “quadrumana”.

The ostrich is a bipedal adept sprinter. Its high-mass muscles are at the top of its legs, with relatively thin, long lower legs. Quadruped antelope prey species that are good sprinters embody the same logic of lowered inertia in the lower limbs. Modern man, who has inherited the gross features of australopiths, is known to be a poor sprinter, see this extract from a table by
http://www.infoplease.com/ipa/A0004737.html

Cheetah70.00mph, Thomson's gazelle50.00, Wildebeest50.00, Cape hunting dog45.00, Hyena40.00, Ostrich40.00, Zebra40.00, Jackal35.00, Rabbit (domestic)35.00, Giraffe32.00, Cat (domestic)30.00, Wart hog30.00, Human27.89, Elephant25.00, Black mamba 20.00

Glad to hear we can outsprint an elephant and a mamba. Seems we can also outsprint a squirrel, chicken, house mouse, spider, three-tailed sloth and garden snail.

Oldskeptic wrote:
JayJay wrote:
It’s standard atheist operating procedure to reserve weapon use to a creature with “smarts”, as part of their origin myth of man-the-atheist. In doing that, atheists have managed to fuck up the history of human evolution, inverted it from the truth that our ancestors were led by the nose through the logical implications of creative relations between African species.


Which atheist said that it takes human intelligence to use a stick or a rock as a weapon? It wasn't me. And what is this atheist origin myth, did I miss a meeting? How have atheists fucked up the history of human evolution, by leaving God out of the process?


You said, á propos of australopiths supposedly not having had an optimized defensive weapon using :

And with a brain the same size a chimp you think that australopithecus had any more of a clue than chimps do today? You're projecting human like traits on a primate with a brain 1/3 the size of the human brain, a brain only 2/3 the size of homo habilis; the first rudimentary tool maker.


Your post illustrates this fuck-up . You consistently discount the ability of any predator to have acted on the australopiths. According to you hyena were mere scavengers, sabretooth too big and slow, leopard weren’t there at all. In this way you avoid discussing how other actors could have impacted on the morphology of human ancestors. Without such driving factors, the human origin narrative becomes an act on a stage as opposed to a process acting on a creature embedded in a set of relations. You claim it’s impossible to model the relationship between our ancestors and the biome they lived in. But it’s the relations between things in this biome that worked together in just such a way as to create the australopiths- and in turn Homo out of them. I say “create” because this process produced more out of less- a talking animal where a billion years earlier there had only been algal mats. You might agree with some of that in the abstract, but the actual narrative you dismiss is the one of embeddedness and intimate relations within a greater context.

Another aspect of the fuckup has to do with the role of role of mindfulness in the human origin narrative. You insist on associating tool making with the brainier Homo although we have been discussing the ecology of Australopiths, who according to Wiki, do appear to have chipped pebbles to make Oldowan tools. The essential element you aren’t admitting into the origin narrative is that of mindlessness - that our ancestors could have been mindlessly led by the nose along a creative path- No Clarke/Kubrik-style ape epiphany, no narrative of the intellectual awakening of Man.

Oldskeptic wrote:
What does this [the pom-pom crab] have to do with anything except you trying to refute something I didn't say?

You did say this: ”And with a brain the same size a chimp you think that australopithecus had any more of a clue than chimps do today? You're projecting human like traits on a primate with a brain 1/3 the size of the human brain, a brain only 2/3 the size of homo habilis; the first rudimentary tool maker.”

An animal doesn’t need a brain of any size to speak of, to optimize its use of a found object to defend itself. If chimps are clueless at it and australopiths were proficient, that had nothing to do with their brain size but with the particularities of their relationship with other creatures.
Oldskeptic wrote:
JayJay wrote:
There is a characteristic mean-spiritedness or selfishness behind this intent to pull every animal ability towards the present exalted humanity. Animals as simple as caddis worms use materials in well-chosen sophisticated ways, It’s absolutely endemic throughout nature, up to crows winkling food out of bottles using wires.


What the fuck are you talking about?

I was trying to identify an aspect of the character of the atheist origin narrative that has been constructed over the last decades.
Oldskeptic wrote:
JayJay wrote:
Come, take up my challenge to visualize a better body plan than Australopithcus, for applying simple hand-held weapons against predators.


No one is disputing that Australopithecus had hands capable of grasping sticks or stones or tree branches so I don't know what you're going on about.


Optimisation of a weapon-using defense would go further than just a hand-grip, it would work on the whole body. Picture the following non-optimal forms:
Picture a knuckle-walking ape having to carry a stick and a stone everywhere, in case it’s attacked while foraging. Compare that with a bipedal hominin, tucking a stick under its arm and holding the stone while walking.

Picture an ape confronting a leopard eye to eye, compared with a tall australopiths, ready to smash a stone down on the leopard’s skull.

Picture a ground-living ape, good at sprinting so with spindly shanks, confronting a hyena that darts around the side
Picture a curve-backed chimp smashing a stone onto a hyena’s skull, compared with a long-straight- backed australopiths doing that.
In a nutshell, what makes us better at tennis than a chimp is having inherited some of this optimisation.
Oldskeptic wrote:
Chimps on patrol groups don’t carry sticks and stones. What would happen if a hominoid species needed to do so while foraging? The great doors of logic would shift around them into a new of co-evolution with those sticks.


What are these great doors of logic shifting then? Were you talking about the sticks thinking logically?


Carrying a stick around and using it in a context that optimizes it’s quick and forceful use in a group defense of a primate troop, would dramatically change the constraints determining morphology. For example if the eye teeth are not used to rip chunks out of the predator that allows the teeth to lie in a plane and so the jaw can adapt to move sideways, grinding hard seeds.- as with Paranthropus. More portentously, a thinking head that doesn’t double as a war-head has different constraints. Socially a successful fighting defense allows for longer nurturing of young.

No the sticks don’t think logically.
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Re: "New eye discovery further demolishes Dawkins"

#316  Postby Thomas Eshuis » Jun 24, 2014 8:33 am

More assumptions based on ahistorical inferences.
No evidence whatsoever.
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Re: "New eye discovery further demolishes Dawkins"

#317  Postby theropod » Jun 24, 2014 1:10 pm

Thomas Eshuis wrote:More assumptions based on ahistorical inferences.
No evidence whatsoever.


...and a continuation of the "atheist agenda" bullshit that's been addressed a great many times.

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Re: "New eye discovery further demolishes Dawkins"

#318  Postby DavidMcC » Jun 24, 2014 3:06 pm

halucigenia wrote:
DavidMcC wrote:
It is not a strawman. I now have a page reference for the bad biology:
"Climbing Mount Improbable", chapter 5, page 153, Fig,5.14 from Nilsson and Pelger.
The reader is left to assume that the "fish" referred to in the fish-eye sequence is a vertebrate fish, because othing to the contrary is mentioned in the text. The sequence I have referenced is not the only one I know of, but it is the only one that I can find at the moment.
I accept that RD was not the instigator of this mistake, but he certainly propagated it, aided and abetted, it seems, by an aquaintance of his, who works for Nikon!
Well, there's no reference there to the backwards retina, nor to molusk eyes at all, never mind “one extra step to turn the retinae inside out”.
Come on, admit it, you were making this up all along. :nono:

DavidMcC wrote:You can kid yourself, maybe, but I have found another old reference, this time in "The Greatest Show on Earth", chapter 11, "History written all over us", p354:
"But now, suppose I tell you that the eye's 'photocells' are pointing backwards, away rom the scene being looked at. The wires connecting the photocells to the brain run all over the surface of the retina... That doesn't make sense...". (My bold) His problem might be that Nikon don't make self-maintaining CCD arrays, so his technical advice was bad from the start. (He quoted his Nikon friend at some point, on camera design.)
Quite, as I thought, this is a separate claim from the sequence of possible steps to form a modern vertebrate or cephalopod eye. It is a claim that the initial arrangement "...The wires connecting the photocells to the brain run all over the surface of the retina... That doesn't make sense..." rather than anything about its subsequent evolution to form a "camera" type eye which then had to take “one extra step to turn the retinae inside out”.
His point, and the title of the chapter "History written all over us" confirms this, is that it is historical happenstance that the structure of the eye in vertebrates happened to be the way that it is in respect of the inverted retina and that it became the way that it currently is with respect to its current functionality simply because of this, rather than because of the foresight of an intelligent designer.
Well of course there were no "foresights of an intelligent designer". HOWEVER, the inverted retinal structure turned out to be a lucky break for the vertebrates. Without that bit of "bad design" we would have the same problems as invertebrates with our eyes failing after only a few years in a photopic environmnent, or having to ut up rwith the "cheap and cheerful" stalk-eyes of some lobsters, or as with many ant species, having short-lived servants to collect the food while the queen stays underground, etc , etc.
Even if Nikon did decide to make self-maintaining CCD arrays, without referencing vertebrate eye structure, do you think that they would have started off with a CCD array "pointing backwards" and build from there, or do you think that at some point they would even take the step to turn the array the other way around and re-design from there as you have suggested that Dawkins thought happened in the evolution of the vertebrate eye? Are you suggesting that this would be "good/intelligent" design practice? :ask:
Building a self repairing CCD array that requires software to ignore the wiring running all over the surface and the point at which all the wiring all goes through the array at one position might make it possible but it would still seem like a kludge to me. :dunno:

Oh, gosh, where to start! It's a pity that my original posts in richarddawkins.net are lost, because I went to great lengths there to marshall the evidence. Maybe NineBerry can actually supply the missing content as he claims?

On the photoreceptors "facing the wrong way", that was one of RD's worst mistakes. They DO NOT FACE BACKWARDS! What actually happens, if you know the biology, is that the photo-receptor cell body guides the light through to the outer segment, where the opsin discs are. This narrows the aceptance angle for light received by any one photoreceptor, at the price of losing some of the light (but light that would only cause resolution and glare issues in any case).
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Re: "New eye discovery further demolishes Dawkins"

#319  Postby DavidMcC » Jun 24, 2014 3:12 pm

halucigenia wrote:Come on, admit it, you were making this up all along. :nono:

No, I damn well wasn't! Dawkins reson for publishing the simulation scheme already mentioned was that he saw parallels between them and various actual eye types. The problem was that all except the last were, or could have been, mollusc eyes, whereas the final one was a vertebrate eye (the penultimate being an octopus eye)! The gross structural difference between those last two was masked by the vagueness of the diagrams.

EDIT: In short, I am saying that Dawkins was so keen to show what a "bad idea" the vertebrate eye is, that he failed to realise the big advantages over any invertebrate eye that it had, not withstanding the smaller problems associated with the more complex layout. Loss of vision is a bigger problem than the snags with vertebrate eyes, which are two "expensive" to simply throw away and replace every few years.
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Re: "New eye discovery further demolishes Dawkins"

#320  Postby DavidMcC » Jun 24, 2014 4:50 pm

... BTW, halucigenia, although self-maintaining CCD arrays do not exist, AFAIK, the technology for self-repairing circuitry does exist, and, guess what? It requires that the wiring be on top!

Self-repairing circuits
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