Remember arch-Darwinist Richard Dawkins’ assertion:
Any engineer would naturally assume that the photocells [of the optical device, or eye] would point towards the light, with their wires leading backwards towards the brain. He would laugh at any suggestion that the photocells might point away from the light, with their wires departing on the side nearest the light. Yet this is exactly what happens in all vertebrate retinas. Each photocell is, in effect, wired in backwards, with its wire sticking out on the side nearest the light. The wire has to travel over the surface of the retina, to a point where it dives through a hole in the retina (the so-called ‘blind spot’) to join the optic nerve. This means that the light, instead of being granted an unrestricted passage to the photocells, has to pass through a forest of connecting wires, presumably suffering at least some attenuation and distortion (actually probably not much but, still, it is the principle of the thing that would offend any tidy-minded engineer!).” (Dawkins R., “The Blind Watchmaker,” 1991, reprint, p93).
It’s old news (2007) that “backwards wiring” in the retina does not present a problem; Muller glial cells act as fiber optic cables to deliver light right through to the eye’s photoreceptors:
Although biological cells are mostly transparent, they are phase objects that differ in shape and refractive index. Any image that is projected through layers of randomly oriented cells will normally be distorted by refraction, reflection, and scattering. Counterintuitively, the retina of the vertebrate eye is inverted with respect to its optical function and light must pass through several tissue layers before reaching the light-detecting photoreceptor cells. Here we report on the specific optical properties of glial cells present in the retina, which might contribute to optimize this apparently unfavorable situation. We investigated intact retinal tissue and individual Müller cells, which are radial glial cells spanning the entire retinal thickness. Müller cells have an extended funnel shape, a higher refractive index than their surrounding tissue, and are oriented along the direction of light propagation. Transmission and reflection confocal microscopy of retinal tissue in vitro and in vivo showed that these cells provide a low-scattering passage for light from the retinal surface to the photoreceptor cells. Using a modified dual-beam laser trap we could also demonstrate that individual Müller cells act as optical fibers. Furthermore, their parallel array in the retina is reminiscent of fiberoptic plates used for low-distortion image transfer. Thus, Müller cells seem to mediate the image transfer through the vertebrate retina with minimal distortion and low loss. This finding elucidates a fundamental feature of the inverted retina as an optical system and ascribes a new function to glial cells. (open access)
However, the latest is that Muller cells can also concentrate light and deliver it directly to cones, to improve day vision:
Zooming in on guinea pig retinas under a confocal microscope, the researchers found that each Müller cell was coupled to an individual cone photoreceptor, and that nearly 90 percent of all cone cells were linked to Müller cells. The optical-fiber effect could increase the number of photons reaching a single cone cell nearly 11-fold at its peak concentrating power, but had only a minimal effect on the light reaching rod cells.
“How optimal light guidance is matched to the absorption spectra of the cone photoreceptors is very surprising,” says Franze, who was not involved with this study. Diameter and refractive index are the “two factors [that] determine the color that optical fibers can guide efficiently,” says Labin. “Our immediate next step is to understand the exact mechanism that creates this special phenomenon.”
Here’s the abstract:
Vision starts with the absorption of light by the retinal photoreceptors—cones and rods. However, due to the ‘inverted’ structure of the retina, the incident light must propagate through reflecting and scattering cellular layers before reaching the photoreceptors. It has been recently suggested that Müller cells function as optical fibres in the retina, transferring light illuminating the retinal surface onto the cone photoreceptors. Here we show that Müller cells are wavelength-dependent wave-guides, concentrating the green-red part of the visible spectrum onto cones and allowing the blue-purple part to leak onto nearby rods. This phenomenon is observed in the isolated retina and explained by a computational model, for the guinea pig and the human parafoveal retina. Therefore, light propagation by Müller cells through the retina can be considered as an integral part of the first step in the visual process, increasing photon absorption by cones while minimally affecting rod-mediated vision. (You have to pay to read the article.)
The “bad design” argument gets worse every time we hear about it.
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21 Replies to “Backwards eye wiring: New function found for claimed “poor design””
why is it very surprising?
what were they expecting instead?
Definitely I would call it very interesting, but not very surprising.
Did I miss something?
I look forward, with much anticipation, to reading a detailed description of the exact mechanism that creates this special phenomenon. That must be very exciting!
I just don’t see it. Perhaps I have a blind spot.
The paper appears to be available in full here:
and downloaded in the “View” section.
News link points to doi:10.1038/ncomms5319 behind a paywall,
while your link points to doi: 10.1016/j.cell.2014.03.004.
did I get this wrong?
My apologies – just had a couple of windows open and copied the incorrect link … however, the one linked to above is also interesting :).
This is the link I should have posted:
Yes, the link you posted first is very interesting too.
“The ‘bad design’ argument gets worse every time we hear about it.” – Absolutely. Every time I hear the argument, it always ends up based on ignorance in the end. Asserted with arrogance even after research proves the “bad design argument” of the day wrong.
The odd thing is how presuppositions still drive conclusions. Optimization of the eye would be “exactly what evolution would predict” in the view of Darwin or Wallace. Now bad design is “exactly what evolution predicts”.
Conversely, “an infinite gradation of species” would be what the principle of plentitude in theology would have predicted two or three centuries ago, whereas now it’s what supposedly refutes creation by God.
Let’s face it. The “bad design” argument is made only because Darwinists are not interested in science but in finding ways to attack the Christian doctrine of an all-knowing and all-powerful God. I personally do not subscribe to this doctrine but the Darwinist argument just demonstrates that evolution has never been about science but about religion. The same can be said about their arguments for vestigial organs, junk DNA, multiple parallel universes and the Copernican principle. Darwinism is voodoo science.
That’s probably part of why eyes seem to perceive brighter than cams.
Lesson, if you do not know in detail how a design works, why, don’t jump to conclusions about how poor it is.
This following quote on the optimality of vision is beautiful,,
A finding to which Newton, who studied light, would quip,,
Dolphin-inspired sonar overcomes size-wavelength limitation – Oct 08, 2014 by Lisa Zyga
Excerpt: ,,, Most sonar sources consist of large arrays, and the total size of the arrays is much larger than the wavelength. This problem is known as the size-wavelength limitation.
While this problem plagues man-made sonar, Yangtze finless porpoises don’t seem to have the same limitation.,,,
the animal has,, a relatively small head (compared to man-made sonar) that can manipulate acoustic waves into a beam with high directivity. Porpoises and dolphins use these highly efficient biosonars for foraging, avoiding predators, and group coordination. Studies have shown that, despite serious vision degradation in water, dolphins can locate centimeter-sized objects 100 meters away using echolocation.,,,
Now a team,,, has designed and constructed a biomimetic sonar projector based on dolphin biosonar that achieves high directivity with a subwavelength sound source, overcoming the size-wavelength limitation.,,,
“The biomimetic projector breaks the size-wavelength limitation of traditional man-made sonar systems and provides a new concept for the realization of directional acoustic devices in the subwavelength regime,”,,,
“[Before now,] the compromise in size or frequency has inevitably brought many serious problems, including large physical size for low-frequency sound beams, high power consumption, and strong attenuation at high frequencies that reduces the detection distance,” he explained. “Therefore, it is important to be able to operate a directional sonar in the subwavelength range, which allows the sonar device to be made in small size with high resolution.”
The researchers’ work builds on their recent computed tomography (CT) studies of the complex structure of dolphin biosonar. The CT results show that the Yangtze finless porpoise has three main acoustic elements in its head: a skull, melon (fatty tissue), and air sacs. The researchers designed elements to mimic each of these features: a steel structure to mimic the skull, a gradient-index material to mimic the melon, and an air cavity to mimic the air sacs.
“These three elements collectively could manipulate the omnidirectional wave generated from a subwavelength source into a highly directional one,” ,,
By successfully mimicking a dolphin’s acoustic elements, the researchers could achieve a very high-performing sonar system using a single sound source. Experiments and simulations showed that the bio-inspired sonar system could have both a miniature size and high directivity, breaking the size-wavelength limitation.
Compared to the traditional strategy of using a horn for making directional beams with a bare subwavelength source (without all of the dolphin-inspired acoustic elements), the new biomimetic projector has superior angular resolution by an order of magnitude, in addition to other advantages. As it does not require complex circuitry, such a sonar system also has low energy consumption and very low cost.
These properties make the bio-inspired sound projector promising for applications in underwater sonar, medical ultrasound, and other related areas. The researchers also want to investigate what happens when part of a dolphin’s biosonar is damaged.
“In the future, we will focus more on the function of each component and the physical mechanism of beam focusing using gradient materials,” Cao said. “In principle, a dolphin’s acoustic structure should affect its biosonar function. But, we found a dolphin with partially damaged acoustic structure that lives independently and is able to avoid vessels, which suggests its echolocation ability is still intact. Our next goal is to find out why such acoustic structure damage did not cause catastrophe in the dolphin’s life.
Of related interest:
Sperm whale Vs giant squid – video animation
Any guesses as to why evolutionists and cosmologists are so ofter VERY SURPRISED by what they find in their research and experiments?
How often do we hear these words?!!
It’s like a constant refrain. What it tells me is that the paradigm they are using to make predictions, the line of thinking that results in their “expectations” must be wrong!
It’s more than a case of needing a bit of tweaking. It needs a whole overhaul, but evolution is so pliable that nothing can falsify it. Another big tweak or overhaul and they are good to go another week until they have to do it all over again.
And they call it “SCIENCE”!
This is Darwin’s legacy to us. The way we do science has forever been changed and what we are willing to consider as science has changed as well.
Where else but historical science can scientists get away with such tomfoolery?!
How many times do we hear the Darwinits’ say “we’re surprised” ? haha…
The only bad design here are their arguments against God.
Evolution of the Gaps
Thanks to BA77 @ 13.
When I read BAs comments, and especially the video of the whale, I harkened back to a previous post of mine where I talked about sonar processing. The article is at:
and here are a few sonar snippets I wrote at the time:
In the body of the article –
“In our modern technological world we have analogies to that busy room. Our Navy ships scan the depths of the ocean with sonar. The pulses transmitted from the sonar antenna bounce off; the ocean floor, schools of fish and even the surface of the ocean, returning a bewildering stream of noise that the computers of the sonar must sift through, filter and cluster to present the operators and commanders an array of potential hazards and threats to the fleet. These sophisticated sonar system require sophisticated computational systems and large amounts of memory storage to accomplish the task in real-time. But most fundamentally they require intelligent designers to create the systems required.”
And at comment 4 –
“I was working at a Navy lab in San Diego on a project that was building a prototype for the Advanced Lightweight Torpedo. I was a very junior computer programmer carrying water for some really smart folks.
These folks put acoustic pattern recognition, and more, into a very small torpedo sized package, and I was fortunate to witness mush of this amazing development.
I’ll skip the part of generating the sonar pulse and go to the receive processing as much as I can recall.
First of all, the returning signals from the pulse came from a variety of sources; – reverberation from the ocean bottom, the ocean surface, and from the volume of water containing the pulse; – discrete signal sources such as schools of fish, rocks and other underwater terrain features; and lastly the potential targets.
I was not then, nor have I ever been, an acoustics engineer, but I can appreciate the knowledge that was behind the algorithms used in this processing.
The surface, volume and bottom reverberation filtering I suspect was the easy part, maybe as simple as filtering out particular frequency bands as noise.
The discrete object filtering however, I suspect took some very sophisticated algorithms in order to separate out fish, rocks etc. from the potential targets.
Once the noise was for the most part filtered out, what was left was a set of discrete, and potential targets.
The next step, as I recall, was called ‘clustering’ where returns in close proximity to one another were combined into single discrete items.
I don’t recall, these many years later what was next, but there was probably a ‘tactical’ set of algorithms that analyzed such attributes as motion, size, dispersions over time etc. in order to pick the most likely target.”
The whale pinging animation is very close to what I recall we were seeing as we reconstructed the torpedo sonar processing on a 3-D graphics computer way back in 1975.
Thanks for the memories.
Good grief. How many times have we been over this same subject?
Eye Evolution – It’s Impossible (Part 1)
Eye Evolution – It’s Impossible (Part 2)
Eye Evolution – It’s Impossible (Part 3)
Go and stand in the corner, Dawkins! And face the wall.
‘How many times do we hear the Darwinists say “we’re surprised” ? haha…’
We used to hear it almost every day, humbled, and I was getting a bit worried that maybe Forrest had retired, and taken his box of exciting, new, Darwinian, chocolates with him.
Discovery that glial cells in the retina assist in cone (daytime) vision would interest any evolutionist, but would not shake his/her acceptance of natural selection. Given that the retina is indeed in backwards in mammals (not in all species) and that acute vision can reasonably be expected to increase fitness, selection for a mutation in glial cells that then have this vision-enhancing property would be predicted by natural selection, were that mutation to occur.