Evolution and the eye

This looks like top grade creationist bait to me.

Oooh, you've brought in religion.
On a scientific thread about evolution and the eye.
 
If you put cheese in a trap, you don't have to have a sign next to it saying.
"Hey mice, nice safe tasty cheese here. Come and take some."

OK that might not work with mice, but creationists can read.
 
Yes, but rpenner has not specified any religious nature to this, we are simply assuming that creationist are still believe the evolution of the eye is a viable argument against evolution and that they will imminently attack such a thread, which they haven't. Perhaps they are stupider then we think? Compare to "Evolution and denial of evolution: add your posts here." sticky.
 
LogicTech said:
Hasn't the evolution of the eye, and other specific organs, been studied for a very long time though?
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Yes, and they continue to be studied. We haven’t ‘solved’ the evolution of internal organs. There will always be unanswered questions that need to be studied.
 
Hercules Rockefeller said:
Yes, and they continue to be studied. We haven’t ‘solved’ the evolution of internal organs. There will always be unanswered questions that need to be studied.
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it more of the amount of detail that can be collected in near infinite. Perhaps in mathematics it could be describe as recording the digits of pi, we have a very useful approximation of pi just like we have a general understanding of eye evolution, but for science a general understanding in never enough... although it does become ridicules once you get past a 1000 digits.
 
I don't want to be considered a thread killer, so I'll venture in where creationists fear to tread.

The notion of a cell becoming sensitive to light, I can see as a natural process of evolution. It would be a useful adaptation, and, in accordance with evolutionary principles, I can see how that could become an organelle with many light sensitive cells, giving information about size and direction. From there we proceed to a fully fledged organ.
But how did the lens develop?
 
Captain Kremmen said:
But how did the lens develop?
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It appears that this course was adopted in early craniates by causing the ballooning eye vesicle to fold inwards upon itself (Fig. 1e–f). The signal triggering this invagination seems almost certain to have arisen from the outer body wall (surface ectoderm) at a specialized region called a placode. Even though this region is given the name “lens placode” in modern vertebrates, our view is that its original function was likely to have been in triggering invagination of the eye vesicle at a stage in evolution prior to the appearance of a lens.
...
However, for the organisms that subsequently became vertebrates, it seems that the tissue of the placode must have thickened slightly, thereby bending incoming light rays and giving rise to a weak optical lens, providing some slight degree of imaging onto the retina. Provided that the retina was able to process such an image and to send this information to an appropriate region of the primitive brain, then the animal would have possessed a rudimentary ability to resolve spatial images; that is, a simple form of “vision” would have existed
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Or in translation: The cells where the developmental signal to infold the photosensitive cells into a cup-like retina evolved -- were selected further to form a cover. Any natural variation which caused a thickness of this cover or transparancy of this cover would have contributed to the image-forming properties of this proto-lens and thus the lens is naturally selected for.

From "The Origin of the Vertebrate Eye" http://www.springerlink.com/content/n4t036300571k8j4/fulltext.pdf

Also "Opening the “Black Box”: The Genetic and Biochemical Basis of Eye Evolution" has a discussion of the special proteins of the lens.
http://www.springerlink.com/content/p52245164l342056/fulltext.pdf

Finally, in the section "Lens", the article "The Evolution of Complex Organs" addresses both sides of the story, with details in other parts of the article.
http://www.springerlink.com/content/t125078h5p201442/fulltext.pdf
 
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It started as a primitive pinhole camera.
Yes, I think I've seen that theory proposed before.
It does make sense.

OK, try this one. It's a variation on the usual argument, so may interest people more than the standard one about irreducible complexity.

The mammalian eye is advantageous only at an advanced stage of development.
Muscles for focussing, lens, etc need to co-ordinate.
Whereas compound eyes can evolve by simple repetition organisation and refinement.

How come nature selected for single eyes in mammals rather than compound?
Surely the early advantage would be with compound eyes, despite the mammalian eye eventually giving superior vision.
The better, more complex eye, would never get the chance to develop, because it's inferior simpler competitor would outperform it.
 
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Captain Kremmen said:
I don't want to be considered a thread killer, so I'll venture in where creationists fear to tread.

The notion of a cell becoming sensitive to light, I can see as a natural process of evolution. It would be a useful adaptation, and, in accordance with evolutionary principles, I can see how that could become an organelle with many light sensitive cells, giving information about size and direction. From there we proceed to a fully fledged organ.
But how did the lens develop?
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you use the word "organelle" incorrectly. Organelle's dont have cells, cells have orgnanellls. They are the parts of the cell which perform specific jobs like the mitacondria.

What i THINK you mean to say is "proto-organ"
 
Thanks. Definitely wrong word. I meant proto organ

or·gan·elle (ôr′gə nel′)
noun
a discrete structure within a cell, as a chloroplast or centriole, characterized by having specialized functions, a usually distinctive chemical composition, and an identifying molecular structure: often found in large numbers in a particular cell
 
kremmen said:
It started as a primitive pinhole camera.
Yes, I think I've seen that theory proposed before.
It does make sense.
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According to the linked articles, it didn't. There are several different starting forms or directions, and the one that led to the mammal eye was not the pinhole camera form.

kremmen said:
The mammalian eye is advantageous only at an advanced stage of development
The better, more complex eye, would never get the chance to develop, because it's inferior simpler competitor would outperform it.
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Doesn't matter - the compound eye never got started in the ancestors of mammals, and so was not present in the organism to outcompete the other. The selection pressure was on the form that got started, and the improvements to that form outcompeted the inferior versions.
 
The eye are a part of our survival adaptation and evolution. 50% of the brain is used to process the information sent by the eye. Threats in our enviroment are quickly detected and processed by the brain. The better we see, the more likely that we will survive.
 
krokah said:
The eye are a part of our survival adaptation and evolution. 50% of the brain is used to process the information sent by the eye. Threats in our enviroment are quickly detected and processed by the brain. The better we see, the more likely that we will survive.
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Not true.

Since there is no such thing as survival of the fittest, you are just as likely to survive with myopia as without.

http://en.wikipedia.org/wiki/Myopia

The global prevalence of refractive errors has been estimated from 800 million to 2.3 billion.[27] The incidence of myopia within sampled population often varies with age, country, sex, race, ethnicity, occupation, environment, and other factors.[25][28] Variability in testing and data collection methods makes comparisons of prevalence and progression difficult.[29]

In some areas, such as China, India and Malaysia, up to 41% of the adult population is myopic to -1dpt,[30] up to 80% to -0.5dpt.[31]

A recent study involving first-year undergraduate students in the United Kingdom found that 50% of British whites and 53.4% of British Asians were myopic.[32]

In Australia, the overall prevalence of myopia (worse than −0.50 diopters) has been estimated to be 77%.[33] In one recent study, less than 1 in 10 (8.4%) Australian children between the ages of 4 and 12 were found to have myopia greater than −0.50 diopters.[34] A recent review found that 16.4% of Australians aged 40 or over have at least −1.00 diopters of myopia and 2.5% have at least −5.00 diopters.[35]

In Brazil, a 2005 study estimated that 6.4% of Brazilians between the ages of 12 and 59 had −1.00 diopter of myopia or more, compared with 2.7% of the indigenous people in northwestern Brazil.[36] Another found nearly 1 in 8 (13.3%) of the students in one city were myopic.[37]

In Greece, the prevalence of myopia among 15 to 18 year old students was found to be 36.8%.[38]

In India, the prevalence of myopia in the general population has been reported to be only 6.9%.[39][38]

A recent review found that 26.6% of Western Europeans aged 40 or over have at least −1.00 diopters of myopia and 4.6% have at least −5.00 diopters.[35]

In the United States, the prevalence of myopia has been estimated at 20%.[25] Nearly 1 in 10 (9.2%) American children between the ages of 5 and 17 have myopia.[40] Approximately 25% of Americans between the ages of 12 and 54 have the condition.[41] A recent review found that 25.4% of Americans aged 40 or over have at least −1.00 diopters of myopia and 4.5% have at least −5.00 diopters.[35]

A study of Jordanian adults aged 17 to 40 found that over half (53.7%) were myopic.
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