The human eye consists of over two million working parts making it second only to the brain in complexity. Evolutionists believe that the human eye is a product of millions of years of mutations and natural selection. As you read about the amazing complexity of the eye please ask yourself: could this really be a product of evolution?
The lens of the eye is suspended in position by hundreds of string like fibres called Zonules. The ciliary muscle changes the shape of the lens. It relaxes to flatten the lens for distance vision; for close work it contracts rounding out the lens. This happens automatically and instantaneously without you having to think about it.
How could evolution produce a system that even knows when it is in focus? Let alone the mechanism to focus.
How would evolution produce a system that can control a muscle that is in the perfect place to change the shape of the lens?
A visual system
The retina is composed of photoreceptor cells. When light falls on one of these cells, it causes a complex chemical reaction that sends an electrical signal through the optic nerve to the brain. It uses a signal transduction pathway, consisting of 9 irreducible steps. the light must go all the way through. Now, what if this pathway did happen to suddenly evolve and such a signal could be sent and go all the way through. So what?! How is the receptor cell going to know what to do with this signal? It will have to learn what this signal means. Learning and interpretation are very complicated processes involving a great many other proteins in other unique systems. Now the cell, in one lifetime, must evolve the ability to pass on this ability to interpret vision to its offspring. If it does not pass on this ability, the offspring must learn as well or vision offers no advantage to them. All of these wonderful processes need regulation. No function is beneficial unless it can be regulated (turned off and on). If the light sensitive cells cannot be turned off once they are turned on, vision does not occur. This regulatory ability is also very complicated involving a great many proteins and other molecules - all of which must be in place initially for vision to be beneficial. How does evolution explain our retinas having the correct cells which create electrical impulses when light activates them?
Making sense of it all
Each eye takes a slightly different picture of the world. At the optic chiasm each picture is divided in half. The outer left and right halves continue back toward the visual cortex. The inner left and right halves cross over to the other side of the brain then continue back toward the visual cortex.Also, the image that is projected onto the retina is upside down. The brain flips the image back up the right way during processing. Somehow, the human brain makes sense of the electrical impulses received via the optic nerve. The brain also combines the images from both eyes into one image and flips it up the right way… and all this is done in real time. How could natural selection recognize the problem and evolve the mechanism of the left side of the brain receiving the information from the left side of both eyes and the right side of the brain taking the information from the right side of both eyes? How would evolution produce a system that can interpret electrical impulses and process them into images? Why would evolution produce a system that knows the image on the retina is upside down?
Constant level of light
The retina needs a fairly constant level of light intensity to best form useful images with our eyes. The iris muscles control the size of the pupil. It contracts and expands, opening and closing the pupil, in response to the brightness of surrounding light. Just as the aperture in a camera protects the film from over exposure, the iris of the eye helps protect the sensitive retina. How would evolution produce a light sensor? Even if evolution could produce a light sensor.. how can a purely naturalistic process like evolution produce a system that knows how to measure light intensity? How would evolution produce a system that would control a muscle which regulates the size of the pupil?
Cone cells give us our detailed color daytime vision. There are 6 million of them in each human eye. Most of them are located in the central retina. There are three types of cone cells: one sensitive to red light, another to green light, and the third sensitive to blue light.
Isn’t it fortunate that the cone cells are situated in the centre of the retina? Would be a bit awkward if your most detailed vision was on the periphery of your eye sight?
Rod cells give us our dim light or night vision. They are 500 times more sensitive to light and also more sensitive to motion than cone cells. There are 120 million rod cells in the human eye. Most rod cells are located in our peripheral or side vision. it can modify its own light sensitivity. After about 15 seconds in lower light, our bodies increase the level of rhodopsin in our retina. Over the next half hour in low light, our eyes get more an more sensitive. In fact, studies have shown that our eyes are around 600 times more sensitive at night than during the day. Why would the eye have different types of photoreceptor cells with one specifically to help us see in low light?
The lacrimal gland continually secretes tears which moisten, lubricate, and protect the surface of the eye. Excess tears drain into the lacrimal duct which empty into the nasal cavity.
If there was no lubrication system our eyes would dry up and cease to function within a few hours.
If the lubrication wasn’t there we would all be blind. Had this system not have to be fully setup from the beginning?
Fortunate that we have a lacrimal duct aren’t we? Otherwise we would have steady stream of tears running down our faces!
Eye lashes protect the eyes from particles that may injure them. They form a screen to keep dust and insects out. Anything touching them triggers the eyelids to blink.
How is it that the eyelids blink when something touches the eye lashes?
Six muscles are in charge of eye movement. Four of these move the eye up, down, left and right. The other two control the twisting motion of the eye when we tilt our head.
The orbit or eye socket is a cone-shaped bony cavity that protects the eye. The socket is padded with fatty tissue that allows the eye to move easily. When you tilt your head to the side your eye stays level with the horizon.. how would evolution produce this? Isn’t it amazing that you can look where you want without having to move your head all the time? If our eye sockets were not padded with fatty tissue then it would be a struggle to move our eyes.. why would evolution produce this?
Some have claimed that the eye is wired back to front and therefore it must be the product of evolution. They claim that a designer would not design the eye this way. Well, it turns out this argument stems from a lack of knowledge.
The idea that the eye is wired backward comes from a lack of knowledge of eye function and anatomy.
Dr George Marshall
Dr Marshall explains that the nerves could not go behind the eye, because that space is reserved for the choroid, which provides the rich blood supply needed for the very metabolically active retinal pigment epithelium (RPE). This is necessary to regenerate the photoreceptors, and to absorb excess heat. So it is necessary for the nerves to go in front instead.
The more I study the human eye, the harder it is to believe that it evolved. Most people see the miracle of sight. I see a miracle of complexity on viewing things at 100,000 times magnification. It is the perfection of this complexity that causes me to baulk at evolutionary theory.
Dr George Marshall
Evolution of the eye?
Proponents of evolutionary mechanisms have come up with how they think the eye might have gradually evolved over time but it’s nothing more than speculation.
For instance, observe how Dawkins explains the origin of the eye:
Observe the words ‘suppose’, ‘probably’, ‘suspect’, ‘perhaps’ & ‘imagine’? This is not science but pseudo scientific speculation and story telling. Sure, there are a lot of different types of eyes out there but that doesn’t mean they evolved. Besides, based on the questions above you can see how much of an oversimplification Dawkins presentation is.
The human eye is amongst the best automatic camera in existence. Every time we change where we’re looking, our eye (and retina) is changing everything else to compensate: focus & light intensity are constantly adjusting to ensure that our eyesight is as good it can be. Man has made his own cameras… it took intelligent people to design and build them. The human eye is better than the best human made camera. How is the emergence of eyes best explained, evolution, or design ?!
Objection: Why are our eyes not perfectly made ?
Answer: The vertebrate eye is quite an exceptional organ in terms of its function. Light passes through the cornea, then through the lens where it is focused on the retina, which contains the photoreceptors (rods and cones) for detecting this light (see diagram to right). Each rod and cone that receives light fires a signal to the neural apparatus, which transmits the signal to the optic nerve, which goes to the brain for processing. The brain does some fancy processing, including inverting the image and interpreting what is seen (this is a whole other story that cannot be covered here). 2
The invertebrate eye is much simpler and is quite different, especially in the design of its retina. The invertebrate retina is composed of the photoreceptors, which face the incoming light, followed by the neural layer, and the underlying layers that supply nutrients and oxygen through a capillary bed. However, the vertebrate retina is said to be "inverted," since the neural layers face the light and the photoreceptor cells actually face away from the incident light. Evolutionists say that this arrangement was the result of improvised evolution in which obvious errors in "design" were accommodated through successive mutational alterations to make the apparatus work in a functional manner. According to Richard Dawkins, a leading proponent of evolution:
"Any engineer would naturally assume that the photocells 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 ï¿½blind spotï¿½) 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). I donï¿½t know the exact explanation for this strange state of affairs. The relevant period of evolution is so long ago."4
Dawkins doesn't know why the vertebrate retina is designed this way because he doesn't really understand how the eye works. In fact, the retina is designed with slightly suboptimal light gathering abilities so that it will be functional for at least several decades. If it were designed according to Dawkins' "tidy-minded engineer," it would not work at all, as we shall see.
First, we need a short introduction to the physics of light. The electromagnetic spectrum emitted by the sun is composed of many different wavelengths, a small percentage of which are visible to our eyes (370-730 nanometers). The near-visible wavelengths include the longer wavelengths (infrared) and the shorter wavelengths (ultraviolet). The amount of energy within each wavelength is inversely proportional to the wavelength. Therefore, electromagnetic energy that consists of shorter wavelengths (e.g., ultraviolet light) is more energetic.
|Click on animation to enlarge|
Because of continuous damage caused by light, the discs (along with the photopigments) of the photoreceptor cells are continuously replaced by the RPE.5, 6 If this were not the case, the photoreceptors would quickly accumulate fatal defects that would prohibit their function. In addition, the RPE cells contain the pigment melanin, which absorbs stray and scattered light to improve visual acuity. The RPE is in contact with the choroid layer, which contains a very large capillary bed, which has the largest blood flow per gram of any tissue in the body. Why is the blood flow so high in the choroid? Since the RPE and photoreceptor cells are in constant regeneration, they require a high rate of exchange of oxygen and nutrients. In addition, it appears that the high rate of blood flow is required to remove heat from the retina to prevent damage resulting from focused light (the old magnifying glass in the Sun phenomenon).7
So why is Dawkins' "tidy-minded engineer" design such a bad idea? Dawkins thinks that the neural layer should be under the photoreceptors, putting them between the photoreceptors and the choroid. Where would the RPE (which is required to regenerate the photoreceptors) go? If it were between the neural layer and the choroid, it would be too far away from the photoreceptors to constantly regenerate them. In addition, this design would put another layer between the photoreceptors and their blood supply, reducing the exchange of oxygen and nutrients, and minimizing the effectiveness of the choroid in removing heat from the receptors. Dawkins' idea of "good" evolution would prevent the photoreceptors from being regenerated and would likely lead to heat damage. Such a design would certainly fail within the first year of use. It's a good thing that God does not design the way evolutionists would!
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