Quote:
Originally Posted by squall-lionheart
Hi AREQUIPA 
I swear that I do not want to irritate anyone here , Its just questions that I find worth asking .
I didn't ask about the names ...
I asked about a clear fossil records that I didn't find it anywhere & that's include your answer here .  |
I'm not a bit irritated. It's a worthwhile question, but the fact is that researching out the lines of development from common ancestor (probably a Jurassic shrew) to horses one way and primates-humans the other is taking me some time - and there are other threads to attend to and a life to get on with and in fact such info would really not be very informative, since the lines diverged back in the miocene. One could equally give the line of development to pigs, camels, cats and kangaroos.
ــــــــــــــــــــــــــــــــــــــــــــــــــ ــــــــــــــــــــــــــــــــــــــــــــــــــ ــــــ
Quote:
I know about survival advantage .. but I am asking about the very first time a creature could actually see !!!
The basic components of the eye !!!
We are not talking here about a wood plate placed above the other to make a bed !!!
We are talking about an extremely complex organ !!
Another thing ..
How could you evolve an organ out of survival advantage when you don't even knew about it ?
There were no previous experience !!!
Do you understand what I am coming from ?!! 
A simple word like "survival advantage" just wont work here ...
We are talking about How not Why .
When I asked those 2 questions to my Professor( he is an American) he admitted that there are no convincing answers to those questions and they only remains mere speculations .
Why don't you just admit that there are so many questions left hanging without a convincing answer .
There is no shame in that !!
|
I fully agree that there are a lot of questions and a lot of missing evidence. The only case I am arguing is that Evolution theory fits all the facts we have, all new facts adds to the old evidence and it all supports evolution.
Gaps and doubts and all and given that the amazing results of the hit and miss mutation mechanism may seem hard to believe (though the more you learn abut it the more it stacks up) and the actual process of evolution today, especially in humans seems a bit slow and elusive, but it is actually there.
Thus is not only is the best theory that fits the fact, but it is the only theory that fits the facts.
I will post something on the development of the eye, but if I can find it there was a good You- tube talk by Dawkins on the process.
The evolution of the eye
When evolution skeptics want to attack Darwin's theory, they often point to the human eye. How could something so complex, they argue, have developed through random mutations and natural selection, even over millions of years?...
Through natural selection, different types of eyes have emerged in evolutionary history -- and the human eye isn't even the best one, from some standpoints. Because blood vessels run across the surface of the retina instead of beneath it, it's easy for the vessels to proliferate or leak and impair vision. So, the evolution theorists say, the anti-evolution argument that life was created by an "intelligent designer" doesn't hold water: If God or some other omnipotent force was responsible for the human eye, it was something of a botched design.
Here's how some scientists think some eyes may have evolved: The simple light-sensitive spot on the skin of some ancestral creature gave it some tiny survival advantage, perhaps allowing it to evade a predator. Random changes then created a depression in the light-sensitive patch, a deepening pit that made "vision" a little sharper. At the same time, the pit's opening gradually narrowed, so light entered through a small aperture, like a pinhole camera.
(Arq - that's a good theory, where's the evidence?)
Direct evidence has continued to be hard to come by. Whereas scholars who study the evolution of the skeleton can readily document its metamorphosis in the fossil record, soft-tissue structures rarely fossilize....biologists have recently made significant advances in tracing the origin of the eye—by studying how it forms in developing embryos and by comparing eye structure and genes across species to reconstruct when key traits arose.
“Part of the trouble in tracing the evolution of the eye is that soft tissues don’t tend to fossilise. But the eye cavities in the braincase of these 400 million-year-old fossil fish were lined with a delicate layer of very thin bone. All the details of the nerve canals and muscle insertions inside the eye socket are preserved – the first definite fossil evidence demonstrating an intermediate stage in the evolution of our most complex sensory organ.
(But) The ancient limestone reefs exposed around Lake Burrinjuck in New South Wales have produced exceptionally well preserved placoderm specimens with the braincase intact,” Dr Young said.
The palaeobiologist discovered that unlike all living vertebrate animals – which includes everything from the jawless lamprey fish to humans – placoderms had a different arrangement of muscles and nerves supporting the eyeball – evidence of an “intermediate stage” between the evolution of jawless and jawed vertebrates."
http://www.sciencedaily.com/releases...0101193317.htm
Every change had to confer a survival advantage, no matter how slight. Eventually, the light-sensitive spot evolved into a retina, the layer of cells and pigment at the back of the human eye. Over time a lens formed at the front of the eye. It could have arisen as a double-layered transparent tissue containing increasing amounts of liquid that gave it the convex curvature of the human eye.
various sources
http://www.pbs.org/wgbh/evolution/li.../l_011_01.html
http://www.scientificamerican.com/ar...ion-of-the-eye
http://www.sciencedaily.com/releases...0101193317.htm
I did of course come across Sean Pitman's sites questioning various aspects of evolution, including the eye. The questions are valid, but it's the old problem of finding something that can't be answered right now and pretending that this discredits the whole theory. What's worrying is that (in addition to short -sighted arguments for irreducible complexity (1) it is argued that Dr Pitman appears to use science that is actually
wrong to make his case.
This site, while rather rude about ID does point up recent discoveries which show that some of the ID objections to the mechanism of evolution (including the processes of eye evolution) are being answered.
the evolution of retinal biochemistry is advancing quite nicely. Here is a review article from the same time as Behe’s article referenced above (1996-7), showing, for example, the branching pattern of relatedness in the amino acid structure of the opsin group of proteins used in vision. Here is a slightly more recent article from 2002 which reviews the phylogeny of visual protein systems.
The evidence is there, and growing, but creationists have never been bothered much by the evidence. Behe’s strategy is to just show how gee-whiz-complex the biochemistry of vision is then make the classic argument from personal incredulity. He fails to acknowledge, however, that such complexity evolves not so that the system can work at all but to make the system more sensitive, more specific, or more finely tuned. For example, a protein cascade can amplify the signal, allowing greater sensitivity to light. A less light-sensitive system can still work and provide a survival advantage.
http://theness.com/neurologicablog/i...eye-evolution/
You tube.
http://video.google.co.uk/videoplay?...tion+eye&hl=en
(1) asking what use photon - sensitive spots would be to earthworms looked odd even to a layman like me. The survival advantage to a worm being warned that it was about to poke itself into daylight would be obvious, I'd have thought)
Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
Who's the artist?
