the eye

reply to post by DaMod


Eh, check out some of resonance's other threads, and the dozens of other threads by other posters here. eventually we get someone quoting the bible as evidence. Nipping that silliness in the bud seems like a fairly sound, if somewhat distracting preventative measure.

Heya,

Well all of us certainly didnt evolve at the same time. We already had eyes and legs and hands and feet before we evolved into Homo sapiens.

The eye and the parts of the visual cortex are one system that evolved together perhaps at the same time, but independantly of other systems in organisms.

And as some posters have mentioned the human eye is very badly designed... so although im willing to beleive in the possibility of a creator i doubt hed design an eye that is built inside out.

The axons of the light receptive nerves in the retina (axons are the long "cable" bits of a nerve cell) are infront of the photosensative receptor parts of the nerve. So the light has to get past a barrier of tangled "cables" before it is even detected in the first place. Surely a smart god would put the two the other way around?

Also eyes arnt all that complex.... its just a cavity in the head layered with photosensative nerve cells, which got clossed off to prevent fluff coming in and filled with fluid to help light diffraction (fluid makes sense, stos the cells drying out and lets you give them the nutrients you want, may have been an accident at that). The single conmplicated part of the eye is the lense... but even that is easily explained.

If youve shut away your precious and sensative photoreceptive cells, you need a way to get light to them, so you have the see through bit. Evolution takes care of the rest. The animals who can control the muscles to stretch the lense can focus better hence see better, hence die less. So muscle dexterity or strength in the eye is selected for.

Im a lot more impressed with organs like the liver, does 500 things at the same time and can regrow from 10% of its original mass.

~TR

ah the old eye question ...

A big gun that creationism people always throw at you.

how can something so complicated have evolved on its own?........

just like everything else did slowly over millions and billions of years... want proof about the eye?

There are blind salamanders that have lost there eyes (FACT) over time due to living in total and utter darkness .... so if evolution was in play and a creature loses a feature due to locale and environment.

For me this is proof .. these creature did have fully functioning eyes but lost them over time due to conditions

Yes evolution can make something complicated and unmake it just as easy .
Blind salamanders

Moving up the state, the two populations are divided geographically, with the dark, cryptic form occupying the inland mountains and the conspicuous mimic living along the coast. Still farther to the north, in northern California and Oregon, the two populations merge, and only one form is found. In this area, it is clear that what looked like two separate species in the south are in fact a single species with several interbreeding subspecies, joined together in one continuous ring.

The evolutionary story that scientists have deciphered begins in the north, where the single form is found. This is probably the ancestral population. As it expanded south, the population became split by the San Joaquin Valley in central California, forming two different groups. In the Sierra Nevada the salamanders evolved their cryptic coloration.

Along the coast they gradually became brighter and brighter. The division was not absolute: some members of the sub-populations still find each other and interbreed to produce hybrids. The hybrids look healthy and vigorous, but they are neither well-camouflaged nor good mimics, so they are vulnerable to predators.

They also seem to have difficulty finding mates, so the hybrids do not reproduce successfully. These two factors keep the two forms from merging, even though they can interbreed. By the time the salamanders reached the southernmost part of California, the separation had caused the two groups to evolve enough differences that they had become reproductively isolated.

In some areas the two populations coexist, closing the "ring," but do not interbreed. They are as distinct as though they were two separate species. Yet the entire complex of populations belongs to a single taxonomic species, Ensatina escholtzii.

Ring species, says biologist David Wake, who has studied Ensatina for more than 20 years, are a beautiful example of species formation in action. "All of the intermediate steps, normally missing, have been preserved, and that is what makes it so fascinating."

SOURCE


So in closing here we have a documented case of a single species .. starting at a common point and diverging into two separate species due to conditions and location. in fact every part of the evolutionary process is available to see in these creatures from beginning to end .....

in closing if its light your gonna need eyes .. if its dark your not so evolution will make sure you lose them.

Btw the blind salamanders are considered predators so i guess the loss of eyes make them quite dangerous in there habitat i guess evolution must have provided them with upgraded senses to cope with there living conditions...