Evolution and its Adversaries (Part – 16)
With failure staring hard on their faces, the evolutionists have attacked the ‘design’ concept. They cite the eye as a prime example of ‘poor design,’ claiming that light in the human eye has to travel through the neuron layers before it reaches the retina photoreceptors. They argue that this design reflects poorly on an Intelligent Designer and provides clear evidence that no designer exists. However, the fact remains that the retina is not a simple information transforming center. During the development of the fetus (in the womb), some of the differentiated cells acquire the strange quality of transferring electrical signals to other cells far away at a distance from them, writes SYED IQBAL ZAHEER.
Michel S Gazzaniga, Director of the Center for Neurobiology at the University of California writes in his book “Nature’s Mind”: “One organ over which the gladiators of evolutionary theory battle, is the eye.” (P. 21)
But why has the eye been chosen to battle over? There isn’t an organ in the body but which creates insurmountable difficulties for the theory of evolution. But perhaps the eye deserves special attention because it was Darwin himself who declared in his Origin that it was a baffling issue. He was committed to the idea of extreme gradualness and the development of the eye did not fit in the scheme. Its dozens of specialized cells, lining up so perfectly, defied chance assembly. That millions of years were required, during which various parts, scattered around, lay idle, waiting for other specialized cells to arrive, for the assembly beginning to see an object, seemed to require a planned construction. It defied his theory of slow, step by step changes. He wrote:
That natural selection generally acts with extreme slowness I fully admit… I do believe that natural selection will generally act very slowly, only at long intervals of time … Slow though the process of selection may be…. As natural selection acts solely by accumulating slight, successive, favourable variations, it can produce no great or sudden modifications; it can act only by short and slow steps. (The Origin of Species, PDF version, p. 123 & 537)
He wrote about the eye:
Although the belief that an organ so perfect as the eye could have been formed by natural selection, is enough to stagger any one … I have felt the difficulty far too keenly to be surprised at others hesitating to extend the principle of natural selection to so startling a length. (The Origin of Species, PDF version, p. 227 & 202)
His camp followers of the modern times, therefore, hasten up with some sort of explanation that their master couldn’t conjure up. The explanation needed was about what were the specialized cells doing, stuck for millions of years at the eye spot, useless for a long time to come, until rest of the parts arrived to complete the system. If the various complicated parts, with complicated functions, did wait, for millions of years, then, that suggests somebody was planning.
Dawkins therefore, the atheist, instead of explaining the route the eye adopted during its evolutionary journey, deflects his readers away from that question, into a maze of explanations about how stupid the design is. He thinks that – without the brain’s Photoshop abilities – “it’s the design of a complete idiot.” (Richard Dawkins, The Greatest Show on Earth, p.354, Black Swan Publications, 2019). But the stupid design is a working eye. According to Dawkins, evolution, having committed blunders in the design of the eye, came back later to do some tinkering, and edge polishing, to make a perfect eye, just as astronauts were sent to the Hubble Space Telescope to tinker its lens when, after launch, it was found to be defective!
Nothing can be more misleading than assuming that the eye is like a camera. A camera, however advanced, is no more than a dialysis machine when compared to a real kidney. No human invention, including computer-assisted cameras, can begin to rival the eye. The eye is capable of self-focusing, adjusts itself for light intensity, has a self-cleaning lens, and sends the data to the brain faithfully after reading out the message brought by the photons reflected from what it sees. Then, in co-operation with the brain, it interprets the message of the photons as images. And more. It also ignores to see what is of no immediate use to it. An eye will immediately shut off if exposed to the sun and keep modifying every micro-second while a camera will continue to film the sun when focused on it. In response to what the ears hear, the eye can display fear, happiness, amazement, anger, love, tenderness, and the most subtle of emotions, bashfulness. It functions for a hundred years.
How does the Eye work?
The in-coming light from an object first passes through the transparent front part of the eye called Cornea. The major task of focusing on objects is done by the cornea; the rest by the lens. Pupil is the black round hole in the center of the eye. Iris is the colored circle that surrounds the pupil. It controls the amount of light that will enter through the pupil. The iris regulates the size of the pupil controlling how much light will be allowed to go through. Passing through the pupil light strikes the lens. From there it is focused on to the retina. The retina contains many photoreceptor cells that convert light into electric signals. These signals are processed further and then the processed message travels through the optic nerve heading to the brain which actually interprets the electric signals into images.
Fig. 16-1: Anatomy of the Eye
The jelly-like lens is not a fixed apparatus like that of a camera. Its size and distance from the retina is controlled by muscles. When the eye has to see a close object the lens is contracted. It happens in micro-seconds:
Fig. 16-2: A more rounded lens can focus on near objects
The lens becomes more elongated (or stretched) to focus on objects that are far away:
Fig. 16-3: A more elongated/stretched lens can focus on distant objects
Retina, (about 0.25 mm thick), is actually part of the brain, with a number of fibers – called optic fibers – between it and the brain proper. It is an amazing structure. It converts the incoming photon into nerve signals.
The cells at the back of the retina have rods and cones which are light receptors. Rods are far more numerous than cones. They are responsible for vision in dim light. Cones are responsible for observing the fine detail and for color vision. Both are in millions. In the very center, there are only cones. This area is about half a millimeter in diameter.
Because rods and cones are at the back of the retina, the incoming light has to go through the other two layers – the ganglion cells and the bipolar cells – in order to stimulate the rods and cones. The arrangement seems to be to prevent light being reflected back, and to restrain scattering around inside the eye.
Rods and cones and the retinal ganglion cells are three types of nerve cells: bipolar cells, horizontal cells, and amacrine cells. Bipolar cells receive input from the receptors. Horizontal cells link receptors and bipolar cells by relatively long connections that run parallel to the retinal layers; similarly, amacrine cells link bipolar cells and retinal ganglion cells.
Fig. 16-5. Note that in actual the retina shown above is merely 2mm thick
One may think of the information flow through the retina as following two paths: a direct path, from light receptors to bipolar cells to ganglion cells, and an indirect path, in which horizontal cells may be interposed between the receptors and bipolar, and amacrine cells between bipolar and retinal ganglion cells.
Each beam of light that hits the eye goes through a series of steps:
- It passes through a thin layer of moisture.
- When light bounces off an object and reaches the eye, it must be bent so that its rays arrive at the retina in focus. Four different surfaces bend the light as it enters the eye: the cornea, the aqueous humor, the lens, and the vitreous humor. When all four of these bend the light appropriately, you see a focused image of the object.
- Light hits the cornea, also referred to as the eye’s “front window.” The cornea is transparent, and is the first layer to begin focusing light within the eye.
- Behind the cornea is another liquid layer known as the aqueous humor. Its job is to maintain pressure levels in the front of the eye as light is passing through.
- Once light has passed through the aqueous humor, it has finally reached the pupil. The pupil is the entryway to the iris.
- Once the pupil determines how much light it will let inside the eye, the job is passed on to the lens.
- The lens figures out how far away you are from the object that the light is reflecting off. It shapes your image into an accurate view of what you’re looking at.
- When light reaches the center of the eye, it’s ready to be processed. It first passes through another layer of moisture, called the vitreous, or vitreous humor. After that, it reaches the final stop in the process: the retina.
- The retina has special machinery called photoreceptors. They are of two types: rods and cones. Rods are used for limited light and color, and cones are used for specific color detail.
Fig.16-6: Rods and cones take light and convert it into electronic signals for the brain to process.
- Then there is an apparatus called Retinal Pigment Epithelium (RPE). This is a tissue layer below the rods and cones which absorbs any extra, unneeded light.
- What happens when the focused light reaches your retina? It triggers a complex chemical reaction in the light-sensitive rod and cone cells. Rods contain a chemical called rhodopsin, or “visual purple,” and cones contain chemicals called color pigments. These chemicals undergo a transformation that results in electrical impulses being sent to the brain through the optic nerve.
- Once the photoreceptors have converted light into an electronic signal, they send a signal to the brain’s visual command center and you have vision.
- When the electrical impulses arrive in the visual cortex of the brain, the brain analyzes the color and light information from the rods and cones and interprets them as light. All this happens almost instantaneously, allowing you to read a book or enjoy a beautiful sunset. Some of the information from the retina is sent to the visual reflex system in your brain. This allows you to react quickly to visual threats. If you see something coming toward your head, your visual reflex system processes this and causes you to duck before you have time to think about it!
- Visual signals pass from each eye along the million or so fibers of the optic nerve to the optic chiasm, where some nerve fibers cross over. This crossover allows both sides of the brain to receive signals from both eyes.
- When you look at a scene with both eyes, the left half of the scene you are watching registers in the cerebrum’s right hemisphere. Conversely, the right half of the scene registers in the cerebrum’s left hemisphere. Putting them together, and removing any haziness or blurring, the brain constructs a single image.
- Scientists know much about the way cells encode visual information in the retina, but relatively less about the lateral geniculate nucleus — an intermediate way station between the retina and visual cortex.
It should be obvious from above, that a complex apparatus like the eye could not have appeared through accidental, gradual mutations taking place over time running in millions of years. Cells reject and degenerate anything within its boundaries that does not serve any immediate purpose. It is not imaginable that the body made, say, a socket in the head by sheer chance, and then waited a few centuries, for Cornea cells to arrive – again by chance – and then waited a few more centuries for chance to play its trick and supply pupil cells, and so on until a fully functional eye appeared a few million years later. Many level-headed scientists have expressed their doubts about the ability of evolutionary process to achieve this amazing feat. W. J. Dakin, the famous British biologist wrote:
“Now it is very difficult to conceive of a complex structure, complex as these eyes, being the final result of a sifting by natural selection of a large number of chance variations, stress being laid on external factors. Indeed there is grave doubt as to whether the presence of any variations that might lead to such organs could have any survival value.” (W. J. Dakin as quoted by Michael Denton, Nature’s Destiny, Free Press, New York, p. 358)
It is also obvious that an organism has a complete eye or has none. Half an eye – let us say with the photoreceptors missing – was of no use. Even 95% of the eye is functionless without the missing 5%. An evolutionary biologist Stephen Jay Gould, a giant in science, who won Darwin-Wallace Medal, had asked: “What good is 5 percent of an eye?” (Nature’s Mind, p. 22), and has not been answered.
At all events, where are the organisms with partially developed eyes? There should be numberless around; but there are none, neither living nor in fossils. The best they could do is to point to a bacterium which has a spot sensitive to sunlight. But what’s its function? Further, where are the animals with 3%, 7%, 11%, 15% eyes?
With failure staring hard on their faces, the evolutionists have attacked the “design” concept. They cite the eye as a prime example of “poor design” claiming that light in the human eye has to travel through the neuron layers before it reaches the retina photoreceptors. They argue that this design reflects poorly on an Intelligent Designer and provides clear evidence that no designer exists. In the words of a biologist:
“Evolutionists frequently maintain that the vertebrate retina exhibits a feature which indicates that it was not designed because its organization appears to be less than ideal. They refer to the fact that for light to reach the photoreceptors it has to pass through the bulk of the retina’s neural apparatus, and presume that consequent degradation of the image formed at the level of the photoreceptors occurs. In biological terms this arrangement of the retina is said to be inverted because the visual cells are oriented so that their sensory ends are directed away from incident light.” (http://creation.com/Is-our-lsquoinvertedrsquo-retina-really-lsquobad-designrsquo).
The evolutionists claim that the rods and cones should have come first in the retina, and then the Ganglion and Bipolar cells. They raise this issue instead of presenting a re-designed eye, from start of the light entry to the finished image in the brain. It has been pointed out, however, by the specialists that the retina is not a simple information transforming center. During the development of the fetus (in the womb), some of the differentiated cells acquire the strange quality of transferring electrical signals to other cells far away at a distance from them.
“When the eye, which is part of the brain, becomes active and can transfer information to higher centers in the brain, this information can influence, for a time, the developing dynamics of the basic neural circuits of the brain, Indeed, all sensory stimuli start to bombard the higher brain centers can modulate electrical activity in the brain, which, in turn, can influence brain development.” (Nature’s Mind p. 40)
“Surprisingly at first sight, the retinal neurons are located between the lens and the light-sensitive parts of the photoreceptors. The tissue scatters some light, which leads to loss of light and image blur. The inverted retina has, therefore, long been regarded as inferior. Here, we provide evidence that the inverted retina actually is a superior space-saving solution, especially in small eyes.” (Space-saving advantage of an inverted retina, Ronald H.H.Kröger, Oliver Biehlmaier) – http:// www.sciencedirect.com/science/)
Peter Gurney a British Ophthalmologist of repute writes:
“The ‘inverted’ arrangement of the vertebrate retina, in which light has to pass through several inner layers of its neural apparatus before reaching the photoreceptors, has long been the butt of derision by evolutionists who claim that it is inefficient, and therefore evidence against design. This article reviews the reasons for our having the inverted retina and why the opposite arrangement (the verted retina), in which the photoreceptors are innermost and the first layer to receive incident light, would be liable to fail in creatures who have inverted retinas. I suggest that the need for protection of the retina against the injurious effects of light, particularly with the shorter wavelengths, and of the heat generated by focused light necessitates the inverted configuration of the retina in creatures possessing it.” (Is our ‘inverted’ retina really ‘bad design’? – http://creation.com/is-our-inverted-retina-really-bad-design)
Fig.16-9: The Rod and Cones of the Retina. Rods are blue and Cones are purple.
Refuting Dawkins, Gurney further explains:
“Light at various wavelengths is capable of very damaging effects on biological machinery. The retina, besides being an extremely sophisticated transducer and image processor, is clearly designed to withstand the toxic and heating effects of light. The eye is well equipped to protect the retina against radiation we normally encounter in everyday life. Besides the almost complete exclusion of ultraviolet radiation by the cornea and the lens together, the retina itself is endowed with a number of additional mechanisms to protect against such damage:
The retinal pigment epithelium produces substances which combat the damaging chemical by-products of light radiation.
The retinal pigment epithelium plays an essential part sustaining the photoreceptors. This includes recycling and metabolizing their products, thereby renewing them in the face of continual wear from light bombardment.
The central retina is permeated with xanthophyll pigment which filters and absorbs short-wavelength visible light.
The photoreceptors thus need to be in intimate contact with the retinal pigment epithelium, which is opaque. The retinal pigment epithelium, in turn, needs to be in intimate contact with the choroid (also opaque) both to satisfy its nutritional requirements and to prevent (by means of the heat sink effect of its massive blood flow) overheating of the retina from focused light.
If the human retina were ‘wired’ the other way around (the ‘verted’ configuration), as evolutionists such as Dawkins propose, these two opaque layers would have to be interposed in the path of light to the photoreceptors which would leave them in darkness!”
This is science and scientific way of investigation. In contrast, the evolutionists go round and round, with baseless allegations, evading the main issues, failing to offer any hard science evidence.
Incidentally, if genes are responsible for developing the eye, over ages and ages, the question that arises is:
- How did the genes, inside the cell, in complete darkness within the nucleus, know that there was something to see outside?
- Further, how did the genes know that the things to see were in colors in millions of shades?
- Again, almost all animals are capable of seeing in the dark. Obviously then, for perhaps a million years, humans would have been – sharing the forest with the rest of creations – able to see in the dark. Why then, did they shed the ability, while every other of the millions of species have retained it?
- Finally, why is the human eye so limited in operation, unable to see an electron, or even a single atom, when a frog is “capable of seeing individual photons?” (The Particle at the end of the Universe, p.126, Sean Carroll, Oneworld Publications, 2015). It is the humans who are in need of such sight, not frogs.
(To be concluded)