You refusal to be relavant to topic makes your argument worthless. I was discussing how complex eyes could evolve from simple light-sensitive cells. Then you tried to refute me Ok I read your post #62 and I'll re-post some of what you put down in that message.
What is needed to make a light sensitive spot? What happens when a photon of light impinges on the retina?
When a photon first hits the retina, it interacts with a small organic molecule called II-cis-retinal. The shape of retinal is rather bent, but when retinal interacts with the photon, it straightens out, isomerizing into trans-retinal. This is the signal that sets in motion a whole cascade of events resulting in vision. When retinal changes shape, it forces a change in the shape of the protein rhodopsin, which is bound to it. Now part of the transducin complex dissociates and interacts with a protein called phosphodiesterase, When that happens, the phosphodiesterase acquires the ability chemically to cut a small organic molecule called cyclic-GMP, turning it into 5'-GMP. There is a lot of cyclic-GMP in the cell, and some of it sticks to another protein called an ion channel. Normally the ion channel allows sodium ions into the cell. When the concentration of cyclic-GMP decreases because of the action of the phosphodiesterase, however, the cyclic-GMP bound to the ion channel eventually falls off, causing a change in shape that shuts the channel. As a result, sodium ions can no longer enter the cell, the concentration of sodium in the cell decreases, and the voltage accross the cell membrane changes. That in turn causes a wave of electrical polarization to be sent down the optic nerve to the brain. And when interpreted by the brain, that is vision. So this is what modern science has discovered about how Darwin's 'simple' light sensitive spot functions. From: Michael Behe, 'Design at the Foundation of Life".
You refusal to be relevant to topic makes your argument worthless. I was discussing how complex eyes could evolve from simple light-sensitive cells. Then you tried to refute me with a paragraph that supposedly would explain how simple light-sensitive cells could not evolve. Nowhere in the above paragraph does this explain that. Instead it goes on about what happens when a photon strikes the retina, the light sensitive region of a highly evolved organ (the eye). What does this have to do with the mutational changes that would be necessary for non-light sensitive cells to become very crude, light sensitive patches? Even single celled bacteria display photo-taxis, a result of the ability to sense light. These cells’ systems are nowhere near as complex as what is described above. What you are trying to do is the typical deceitful creationist tactic of misrepresenting the theory of evolution when you cannot refute it. You (and Behe) are pointing to the workings of evolved retina with the insinuation that evolutionists believe that such a complex system could just pop into being with a few mutations.
This is the problem with evolution it ASSUMES that given enough time anything is possible.
A complete lie. All it assumes is that genetic traits that allows the possesing individual to survive and reproduce will tend to increase in frequency, while those traits which do not promote survival will tend to decrease in frequency.
I have made cut and paste error here. I was changing the format of my response and somehow the first three sentences of this paragraph got duplicated. My apologies.
You refusal to be relavant to topic makes your argument worthless.
Seems you forget what you yourself posted! (of course you could have reread it if you had forgotten it but why waste time, better to just insult the opponent and avoid having to go into details):
A: The creature is blind. This has obvious disadvantages as it cannot see predators approaching, and has to rely on sound, smell etc.
B: A random mutation has given this creature a patch of light-sensitive cells (not a problem - see below).
That is exactly what was addressed in Behe's statements in Post# 62 . While your reductionist comment further down is much better than the nonsense Darwin wrote it still misses quite a bit:
Well, your entire body is covered with light-sensitive cells. Your skin can detect heat radiation, can it not? What is this radiation? Infra-red light! It is easy to see how small mutations could lead infra-red sensitive cells to become more sensitive to shorter wavelengths of light, ie. "visible" light. Also, photons of certain wavelengths are absorbed by certain pigments/chemicals, affecting the chemistry of the cell in a manner that the brain may detect.
For one thing, I have never seen the sun with my skin. Doubt anyone else has either. It takes a lot to 'see the light' as Behe shows:
What is needed to make a light sensitive spot? What happens when a photon of light impinges on the retina? When a photon first hits the retina, it interacts with a small organic molecule called II-cis-retinal. The shape of retinal is rather bent, but when retinal interacts with the photon, it straightens out, isomerizing into trans-retinal. This is the signal that sets in motion a whole cascade of events resulting in vision. When retinal changes shape, it forces a change in the shape of the protein rhodopsin, which is bound to it. Now part of the transducin complex dissociates and interacts with a protein called phosphodiesterase, When that happens, the phosphodiesterase acquires the ability chemically to cut a small organic molecule called cyclic-GMP, turning it into 5'-GMP. There is a lot of cyclic-GMP in the cell, and some of it sticks to another protein called an ion channel. Normally the ion channel allows sodium ions into the cell. When the concentration of cyclic-GMP decreases because of the action of the phosphodiesterase, however, the cyclic-GMP bound to the ion channel eventually falls off, causing a change in shape that shuts the channel. As a result, sodium ions can no longer enter the cell, the concentration of sodium in the cell decreases, and the voltage accross the cell membrane changes. That in turn causes a wave of electrical polarization to be sent down the optic nerve to the brain. And when interpreted by the brain, that is vision.
So my post was completely 'on subject'. It was you who did not want to discuss the subject because you were willfully ignoring evidence showing your statements to be false, and you knew it. Without the foundation, the house cannot stand. Without the foundation of the light sensitive cells:
I was discussing how complex eyes could evolve from simple light-sensitive cells.
You would have nothing to work with. Now what all the above has to with the development of the eye is pretty obvious. You need numerous steps to get there and you do not get sight until all the steps have taken place. Now since we know that a mutation which does not provide a large advantage will not spread through the population and die shortly after its appearance, this makes the evolution of the eye-spot impossible.
You also have quite a few problems even after that. To give you an idea of how complex is the sight system, one third of our brains is dedicated just to seeing. However, the place where the rubber meets the road and evolution can never explain is:
Since the “language” of the nervous system is electric signals, each of the many types of receptor cells must convert, or transduce, its sensory input into an electric signal.
From: Sensory Transduction
So what needs to happen here is that information in protein form has to be translated into electrical signals. Now, it's pretty hard for humans to translate from one language even to another fairly similar one. Imagine how difficult it is to translate from protein to electricity! Guess evolution sent all these eye parts to langauge school!