You bring up a good point Karlis. I've seen the same thing occur - even with this very point. I call it labeling. A skeptic, or evolutionist will take your point, define it (what I call labeling) and then actually believe they just proved or disproven a point. I've seen it happen dozens of times in this forum. Then they're shocked when you don't admit you "got owned." It's irrational.

I still would like to see if evolutionists can bring forth a good, sound argument "to prove" evolution of life from inanimate matter; and then this primitive life evolving into more and more complex forms of life.

Of course ... since I am an ignoramus regards scientific terminology, it goes without saying that an article to convince me about evolution of complex life would have to be written in a fairly basic "lay-man's language"; which also contained scientific proof -- NOT just scientific theories.

Or is that too much to ask from proponents of evolutionists?
Karlis

Perhaps you should learn more about science and scientific terminology... or is that too much to ask?

How do you expect people to prove a complex theory to you while dumbing it down immensly too? Do you also want us to prove the theory of relativity to you by "dumbing down" the math and the physics? Sometimes, it just doesnt work that way, and you need background knowledge.

Good to see you know exactly how all science articles are written, highlighting words like 'may' and 'is believed', like this in anyway shows that the scientists researching the topic of eye evolution have no idea what they are taking about. All science articles in research or experiments is done this way. Scientists are conditioned to write this way since their first undergraduate lab course. You can never just write "eye evolution evolved this way and thats final". You can't make such far reaching conclusions based on your research.

Well, if indeed, "All science articles in research or experiments is done this way ..." then I guess I will never be convinced that life evolved from inanimate matter, and continued to evolve into more and mor complex life forms, culminating in Mankind.

I actually was hoping that evolutionists had some real proof for their theories ...
Karlis

Yes we do. I personally wouldn't work in a field that we don't have proof for.
For some reason or another, you have no qualms about gravity, general relativity, chemistry theories, but you are so readily to dispute evolution, for the sole reason that it happens to conflict with your belief system. ALL scientific articles are written in the manner I described, not just evolutionary ones.

Some of us have been asking the same thing from creationists and all we get are misrepresentations of science designed to poke holes in evolution. I have not ever seen evidence of creationism. I have only seen creationists trying to bring down evolution.

Follow me on this, if you will:
The absence of one truth does not equate to the validity of another.

The following argument, in premise and conclusion form, is basically what is seen when I see people trying to debunk evolution:
For you "evolutionists" (misnomer) please pretend for a moment that evolution actually didn't happen. Obviously I believe it did, but for the sake of this argument we're going to temporarily suspend our belief.

1. If evolution is incorrect than creationism must be true.
2. Evolution is incorrect.
------------------------------------------
3. Therefore: Creationism is correct.

This is an invalid statement. Just because one thing is not true it does not automatically make another valid.
You cannot prove creationism solely on "disproving" evolution, not that it looks like anyone can at this point.
In order to prove creationism you actually have to find evidence of creationism, not the lack of evidence of evolution.

Again, another premise-conclusion form argument:
1. Evolution is a scientific theory.
2. The theory of evolution has some holes in it.
-------------------------------------------------------
3. Therefore: Evolution is false

True, the above argument is a straw man, but it is not a straw man to specifically bring down creationism, but rather to prove my point again (sometimes you have to pound it in over and over and over...). You cannot prove Creationism by negating Evolution. Even if evolution were not true that would only mean just that: That evolution wouldn't be true. The opposite of evolution is not creationism, its "non" evolution, if you will. That evolution didn't happen. Just as the opposite of Creationism is not Evolution, it is "non" creationism. Scientists don't try to prove evolution by negating creationism. If creationists actually want to be respected in the scientific community, why don't they actually make an effort to show that creationism is correct instead of that evolution is false?

Proving that evolution is false does NOT prove creationism. Not that any creationist has been able to do so so far, except in his own mind.

Interesting point. I recently stumbled across some good videos on why creationists would have to reject not just evolution, but gravity and pretty much all other scientific discoveries.

Here are the links:
Why YECs must deny gravity, part 1
Why YECs must deny gravity, part 2
Why YECs must deny gravity, part 3
Why YECs must deny gravity, part 4
Why YECs must deny gravity, part 5

This guy is pretty good, he does a nice job with it. I know, I know, the videos are long, but seriously, they are really good. Id appreciate some creationists at least taking a look-see, if only for the sake of debate.

Cimber -- I have no qualms about matters such as gravity, chemistry theories, etc., because such theories are not based (I hope! ???) on suppositions; at least not on such nebulous suppositions/theories as in the wiki article I under-scored in blue.

And you are mistaken that I dispute evolution because it conflicts with my personal beliefs. If anything, I accept that "basic evolution" (??? pardon my overly simplistic phrase) is real. It's just that this wicki article is so obviously lacking in ANY proof -- yet is claimed to prove evolution. As I asked earlier, can you show me any shred of actual proof of evolution in that article? -- I mean proof that is not based on theories?

Thanks for trying to help me understand,
Karlis

And I am constantly going to refer you back to journal articles from Science and Nature. Your not going to get better proof than that. If you are serious about 'searching' for proof then subscribe to the journal.

Evolution isn't based on suppositions either. You obviously never read articles that relate to astrophysics or chemistry or anything else for that matter. They all use the same type of language.

Karlis, I would recommend that when you have the time you watch those videos I posted.

Hhmmm -- you could be right.

I have no argument with that.

Again I agree.

Again, we agree.

Of course; that is obvious.

As far as I can understand it -- creationists can NOT prove that creationism is correct, simply because there is no scientific proof (as I can discern, anyway) for creationism. Creationism simply depends on belief in God as Creator.

I agree that creationists should not base their "proofs" by attacking and disproving evolution.

In my opinion, creationists should examine the proofs supplied by evolutionists, to see if life can evolve from non-living matter, and then evolve further into more and more complex life forms. Unfortunately an article as this one in wicki has no proofs whatsoever. Will you agree with me on this particular point, at least, please?

What you say above is correct. However, seeing the lack of proof for evolution in this wicki article, showed that evolution was only proved in the mind of that particular author. Or, do you disagree?

I can only go by the evidence,
Karlis

Hi again Cimber, in reply, may I again repeat what I asked in the previous post, as follows?

~~~ ... this wicki article is so obviously lacking in ANY proof -- yet is claimed to prove evolution. As I asked earlier, can you show me any shred of actual proof of evolution in that article? -- I mean proof that is not based on theories?

Thanks for trying to help me understand,
Karlis

Yes, I will watch at least one of these videos ... more of them if the first one is interesting AND valid.

However, as I asked Cimber, I will again also ask you;

~~~ ... this wicki article is so obviously lacking in ANY proof -- yet is claimed to prove evolution. As I asked earlier, can you show me any shred of actual proof of evolution in that article? -- I mean proof that is not based on theories?


Now, if no proponent of evolution is able to show where there is proof of evolution in that article; why is it so?
Karlis

If you are going to complain about the scientific term theory, I suggest you learn what it means. Unfortunately for you, anyone with a scientific background understands that it does not mean supposition. It is very difficult to get to the status of scientific theory.
If you want to know where the article got its information, the links to the scientific papers are at the bottom of the page.

But I would not start complaining about terminology you don't understand.

It is no wonder you are beginning to see a trend. I am being absolutely evenhanded here, there is no malicious intent when I say that every time this subject is debated on this board, we come to this exact same point. Creationist supporters, after having their arguments vigourously examined and found wanting, say those words "... it doesn't matter HOW much evidence we come up with..." and every time, the evidence is the same. Every time. I reject, and attempt to counter the same arguments each time (or Cimber, BBall, Leo, etc) mainly because people who don't know better, read these debates, and I do not want them thinking that there is no reply to creationist stories. I know I will never change your, or WWFs mind, but that is not the point.
You ask:

Why would I let false science stand? I just don't understand why you think it's a good idea to agree with something you know is wrong, just for the sake of it. And no, no-one who loves science would ever state anything is a certainty - I'm sure people have expressed this to you before - I have no problem stating that, when things that are considered to be facts by the mainstream of science, they are in fact, facts.

Wait... so what are you arguing?

Ok, awesome. That is as it should be.

...now, you see, that doesn't make sense. "we should not try to disprove evolution to prove creationism. We should instead poke holes in the Abiogenisis hypothesis to disprove Evolution."


Then look at the evidence!
For the Nth time; there are NO proofs for anything other than mathematical conjectures.

I know I am repeating and repeating what I wrote, but ...
~~~ ... this wicki article is so obviously lacking in ANY proof -- yet is claimed to prove evolution. As I asked earlier, can you show me any shred of actual proof of evolution in that article? -- I mean proof that is not based on theories?

I mean, if the wicki article has proof, surely someone can copy-paste those particular sentences from the article, to the UM forum?
Or, is it that there is no proof in the article itself, but there is proof contained in the footnote-sources? Sounds weird, does it not?

Thanks for trying to help me understand,
Karlis

Well, maybe you could help out, by copy-pasting facts about proof of evolution within this wicki article, DogsHead?

Nobody else seems to want to answer, except to point to the footnotes,
Karlis

Sorry -- I missed reading your post earlier, DogsHead.

Ok, now I "think" I understand as to why no evolutionist will post proof/s of evolution within that wicki article.

Just to triple-check with you -- you ARE saying that the only proof for life evolving out of inanimate matter, and then further evolving into more and more complex life forms, is based on mathematical conjectures?

Oh well .. so I was correct that evolutionists base their beliefs on faith. Faith in mathematics, it seems.

Or am I still missing something???
Karlis

Not exactly, Karlis.

What DogsHead is saying is that 'proof' is a term used in mathematics to show a conjecture is 'true'. In science there is evidence, fact and Theory - but they do not use 'proof' such as is used in mathematics because no science can be considered 'exact' as mathematics is (which is not to say science can not show how something is with a VERY low degree of uncertainty).

Hope this clarifies.

As for faith in mathematics, while someone might philosophically consider all things faith-based, can anyone show how mathematics is not exact and is, in fact, based on faith (outside of philosophy)?

Many thanks, Leonardo ... what you write makes sense.

On a different level -- can you possibly explain what are the proofs of evolution in that earlier wicki article? And "why" is nobody willing to address this particular article as having real evidence for evolution?

Thanks,
Karlis

There are no proofs of evolution. There are facts and evidence supporting the theories comprising Evolutionary Theory.

Some of the evidence I would point to in that article (and it is not discussed there in depth, you would have to research it to understand WHY it is evidence) are the mentions of the PAX6 gene which appears to be common among organisms with eyes (or photoreceptors) and seems to be a 'master gene' controlling development of this organ in the organism, and the fossil record showing photoreceptors in various stages of development during preceding (or successive) eras.

What are you talking about? It even has a picture!!!!



We see evidence of eye evolution all the time - the way a baby's eye develops in the womb is exactly the same - but because its growing and not evolving it happens quicker - it still goes through the same stages though.

I wish people would stop using the example of the eye as "proof" that evolution isn't true.

Thanks for your response, Emma. However, I think you may have completely missed the meaning of what I wrote.

I know that, a bay's eyes develop from conception to birth, and so on. But that is not an example of evolution, is it? It's an example of procreation, agreed?

Now, "please" read through the post which I sent earlier (copied below). Try to be very, very objective as you read it, and then please tell all of us just WHERE in this article there is any proof that eyes evolved?

I think you will not find any proof of evolution there, Emma;

PLEASE carefully read the phrases highlighted in blue.
Please note that all these phrases are *conjecture*, and the reader is supposed to accept these *conjectures as proof for evolution*.

What do you really think about this? Is this reasonable or not?
~~~~~~~~~~~


EVOLUTION OF THE EYE – from Wicki: this is your link:-
http://en.wikipedia.org/wiki/Evolution_of_the_eye

Is this article actually supposed to *prove* that eyes evolved???
The article consists of lots and lots of “suppositions” and "theories", plus, detailed information as to how eyes are able to see.

These is absolutely *no proof at all* that eyes evolved, anywhere within this article. FACT!

I will highlight in blue the “suppositions” and "theories" I found in the article.
Would someone please care to show us where is there *any PROOF” in this article, that “eyes evolved”???
-=-=-

[Excerpts from above wicki article.]
…. The development of the eye is considered by some experts to be monophyletic; that is, all modern eyes, varied as they are, have their origins in a proto-eye believed to have evolved some 540 million years ago.[1][2][3] Much of the evolution is believed to have been concentrated in just a few million years: the first predator to gain true imaging would have initiated an "arms race".[citation needed] Prey animals and competing predators alike would be forced to rapidly match or exceed any such capabilities to survive. …

... Since 1802, the evolution of a structure as complex as the projecting eye by natural selection has been said to be difficult to explain.[6] …

… It is a matter of debate whether the "eye" evolved once, or independently in many clades.
The genetic machinery employed in eye development is common to all eyed organisms. This may mean that genes have coded for "eyes" in the first place. Alternatively, they may originally have fulfilled a different purpose, and later been co-opted for use in optical machinery.[8]

… One hypothesis is that the sensory organs evolved before the brain did.[12] …

…The fossil record suggests that eyes appeared during the lower Cambrian period (about 540 million years ago). …One of many hypotheses for "causes" of this diversification (backed up by scant evidence) holds that the evolution of eyes initiated an arms race that caused a rapid spate of evolution.[citation needed]

Since the fossil record, particularly of the Early Cambrian, is so poor, it is difficult to constrain the rate of eye evolution. Simple modelling, invoking nothing other than small mutations exposed to natural selection, demonstrates that a primitive optical sense organ could evolve into a complex human-like eye within under a million years.[13] David Berlinski, an intelligent design proponent, questioned the basis of the calculations,[14] and the author of the original paper refuted Berlinski's criticism.[15][16]

…Early eyes
… the majority of major developments in eyes are thought to have occurred over the span of only a few million years. In the book In the Blink of an Eye, Andrew Parker discusses a theory that the evolution of the eye was the catalyst for the Cambrian Explosion. [21]
[End of excerpts.]

Hope someone can show exactly where and how proof of evolution is presented in this article,
Karlis

Karlis scientific theory requires a lot a evidence and fact to back it up. It is not the same as some one just coming up with an idea and suggesting it. You have to understand scientific terminology and it has been explained, yet you continue to use the same arguments. What is there has been statistically analysed to 95% confidence otherwise it would not be used. It is not supposition it is the result of very hard and long work. If it was just supposition then it would never get published in a journal.

A lot more. I need to know that they are actually doing the best they can.

Clearly it is a subject you do not understand, sporkling. Tell you what go and get your self a BSc and then you'll be in a position to comment.
Failing that subscribe to some scientific journals and read them through.
You comments are insulting to anyone who is a scientist.

I'm not necessarily against evolution, but I was reading through that article on the evolution of the eye, and I did see a lot of conjecture - "may have indicated".... "could have been this way".... "one hypothesis states"..... that kind of thing. I do think Karlis may have been overzealous in colouring some of the sections (not all of them refer to conjecture), but even though I am not opposed to evolution, I must agree that the article seems quite uncertain of the issue.

I understand the requirements of scientific theories are not the same as philosophical/psychological theories, but this article reminds me of the many studies I have read supporting other controversial topics, ie, something along the lines of "Studies have suggested a possible link with controversy x"

Just a thought,

Well -- I'm just about at a loss for words, after reading your reply.

Do you mean that evolutionists look at, and describe in great and minute detail, existing life forms, or aspects of these life forms, from many, different and varied viewpoints; then combine many of these observations into a choreographed script, and then present a THEORY that *purports to explain* how evolution "must have" or "possibly did" occur?

Wow ...
"Say no more; say no more. ... nudge, nudge, ... wink, wink".
Karlis

PS: Please, everybody -- please do not look at my weird attempt at humour as "flaming", or other disruptive tactic,
K

And your comments are belittling to anyone who is not a scientist. If completing a science degree or subscribing to science magazines were the requirement to share opinions on scientific matters, then (and I hope I don't offend your sensibilities), that eliminates 99% of the people who post here. And even if they do a science degree, there is no guarantee that they will arrive at the same conclusion. Someone earlier mentioned Dr Monty White, who did do a science degree (a PhD, even), and he came to the conclusion of Young Earth Creationist ideals.

Though perhaps I could use a similar argument next time I see someone grossly misquoting the Bible - "Clearly the Bible is something you do not understand. Tell you what, go and get yourself a Theology degree and you'll be in a position to comment. Failing that subscribe to a Theological Correspondance Course and read through it". But I don't want to turn this into a discussion on the Bible, so I won't go further than that.

I do see what you are saying, but this is the first post that this member has made since page 55, so I'm just trying to understand why there was a need for such a vitriolic response. As far as I am aware, people are free to share their opinions, regardless of what level of knowledge they have on the subject.

No good scientists make anything definite, especially in biology. You always have to cover your back so to speak. However theory in science has a lot of weight. It means there is a very large amount of supporting evidence.

BTW there is no such thing as an evolutionist.

I feel personally insulted by PA, sorry if I seem angry, but I apologise if I insulted anyone.

Well it is only the Wiki article though, it does provide links for further reading though. I just wanted to show that there is plenty of study on the eye and that the it is not irreducibly complex. Some of it is no definitive, however even looking at extant species you can see animals with vary development of the eye.

And my apologies if I have insulted you, that was not my intent. I was seriously trying to understand the point you were raising. None of us here are scientists (well, there are a few, but most of us are not), and it was perplexing to understand why someone who disagrees with science needs to subscribe to a science magazine to share their thoughts. It's like a person who disagrees with the Bible needing to subscribe to theological seminars in order to share their thoughts. I just didn't see where it all fit together.

All the best, Mattshark

Oh sorry PA. Didn't mean you insulted me!
I was referring to disagreement with science being real. He is in no position to make such a statement. By the same token I do not consider myself in a position to criticise the bible because I simply haven't read it.

That is as I stated as well, but I was addressing the issue that people use eyes as an example where evolution couldn't develop something as complex and that it is "irreducably" so. The development of the foetal eye clearly mirrors that of the evolutionary model, therefore it is evidence supporting evolution.

Ahh, I see. No worries, Matt. All the best

Hi Emma -- I feel that any scientist worth his salt would have issues with what you just wrote, in my opinion.

How can you seriously suggest that, "The development of the foetal eye clearly mirrors that of the evolutionary model ..."???
That's like saying the birth of any animal mirrors the evolutionary model", is it not?

I mean, are you not confusing reproduction with evolution? They are far from being one and the same thing, agreed?

And, "IF" reproduction is accepted by proponents of evolution as PROOF of evolution, I will be most amazed ... and, I think I may give up discussing pros and cons of evolution, if that is proposed by scientists who support evolution.

Hope you can clear up some things here,
Karlis

PS: So -- I gather you will not attempt to show us how evolution was "proven" in the wicki article, where I highlighted the "suppositions" in blue?
K

Get this 'supposition' word out of your head. These are not suppositions. These are conclusions that were met based on the research being done.

All I see here is people talking about HOW evolution happened. There is nobody at all saying that it didn't.
Doug

OK ... are you saying that "conclusions without proof" prove evolution of complex life forms?

If "Yes", then that brings me back to ye olden wicki-article hobby horse; a horse that must be nearly dead by now!

Getting straight to the point:
Is there proof supporting evolution in that wicki article "on evolution of eyes"?
A "Yes" or "No" answer will be fine; except a "Yes" answer will need quotes from that article.

What say you?

Karlis

PS: I will keep bringing up this wicki article, as long as posts here keep on supporting evolution, without giving proof for evolution.
Fair enough, or not? Or, should I draw in my head and quit?
K

Karlis,

When a scientist writes an article they use language which is very different to how we might speak everyday - and I'm not talking of the technical terminology. The uncertainties you notice - the perhaps's, the possibly's - these are all commonly used in scientific literature (and lecture) because science does not claim to set the limits of our knowledge. If it did that science would use definitive language in describing things.

For example (a little extreme but it shows my point) 6 scientists examines a cube they are told is identical when examined from any side. The scientists can each only see 1 [different] surface of the cube and all those are described by the scientists as flat, square and blue. The scientists writes an article describing the cube and, in it, state "the cube appears to be identical in all respects when viewed from any of its surfaces."

Why say "appears to be" instead of "is"?

Because no single scientist can observe and test each side of the cube and because the observation/description of each side of the cube is subjective for each scientist. Also, each scientist is aware of the subjectivity of their own observation. It is, however, a cube and that shape has 6 flat surfaces of equal dimension and none of the scientists are colour-blind. Thus the likelihood the scientists are correct and each side is identical is high - but there is still that uncertainty of subjectiveness and the "I didn't observe it myself" factor. So the conservative language option is used.

*sigh*

You're missing the point. Creationists argue that the human eye is too complex to have evolved from an earlier simpler stage. The evolutionary model claims it changed from a flat, light sensitive patch to an eye in stages, each stage adding a level of complexity to the structure and a level of benefit to the user.

Creationists say this isn't possible, as you take any part of an eye away and it doesn't work.

But the eye of a foetus forms in exactly this way, proving that this sort of growth is possible in nature.

As for you points highlighted in blue, Doug is spot on. Its like saying that gravity is a myth because we don't know exactly how and why it works. But it isn't a myth - you can feel it pulling you down to the ground. Evolution is a scientifically accepted fact - and you are not going to suddenly discover an earth-shattering mistake in the theory by posting bits of wikipedia on a forum.

No, it's not a rhetorical question. It is a completely legitimate question. Are you not claiming, by disproving evolution, that we came into existence by the hand of a creator? Is this not CS? Unless I'm mistaken, it is. Above, you defined CS "is concerned with the idea of promoting the scientific study of the evidence of a "Creator." Is this not your argument, Y?

On Creation Science ... Then how about "Intelligent Design"? Or simply Creationism? Whatever you wish to call it. And in your opening statement, you said that you were going to provide what scientific evidence you can in favor of Creationism. You stated:

... I've decided that the best way to clear this up is to just come out and offer my perspectives and what scientific evidence I can provide. My arguments in favor of Creationism will take the form of the following ...

1. The Creation Itself
2. The Holy Bible
3. Problems with Abiogenesis
4. Problems with Evolution
5. Problems with the Fossil Record
6. Problems with Radiometeric Dating Methods
7. Unexplained Phenomenon
8. Personal Testimony
9. Miracles and Healings
10. Prophecies and Other Proofs

As you know Creationism is really a religious belief and like any other belief; it requires faith. Still, if there is anything to it, we should be able to provide reasonable arguments and evidence supporting it.

Again, are you not trying to prove that humanity came from the hand of a Creator by disproving a well-established theory? Your above statement certainly makes this claim. Or am I mistaken (certainly wouldn't be the first time )?

That said, do you believe Intelligent Design and/or Creationism--whatever you wish to call it--should be taught alongside evolution in our schools?

As for the whole "Eye" argument that has been brought up ... This is a favorite of Creationists and apologists. The eye is a complete mess! How many people use glasses/contacts and/or have to have laser surgery? If you don't, you almost certainly will! Studies have shown by the age of 40 or so, eyesight begins to deteriorate. And what about cataracts? My farther just had the lenses in both his eyes replaced because of cataracts--as has a whole slew of his friends.

Unintelligent Design by Robyn Williams (p., 64-66):

So are eyes perfect? Well, not according to the evidence of the glasses on my nose as I write, nor the immense range of eyes in the animal kingdom, nor the ghastly set up of our eye structure compared to, say, that of the octopus. This is superbly demonstrated, again, in Dawkins’s The Blind Watchmaker and I recommend that anyone still favouring Argument from Personal Incredulity should look at those sections of his book. The detail is overwhelming—and fun. Descriptions of light-sensitive cells pointing the wrong way, of optic nerves barging right through pivotal areas and causing blind spots, of components going bung—the indictment of this ‘divine perfection in design’ is extraordinary. Any thoroughgoing examination of our optical system shows compromise, adjustment, re-routing and patching up. It is like when you buy an old house and every electrician and plumber you call in shakes his head over the bodgie jobs done by his predecessor: ‘Ooooooh dear, I can see what he tried to do there. Hopeless. Had to cover it up with laster. Lucky we found it, mate, or you’d have been in trouble. Must have been an amateur. One less brain cell and he’d have been a Brussels sprout! ’Fraid it’s going to cost.’ Eyes are excellent, and I insist on keeping mine, but let’s not get carried away: we have a case for compensation.

Take Andrew Walker’s recent books on the role of light-sensitive cells in causing the evolutionary explosion two billion years ago. From a world where life was not much more than clusters of single cells or parts thereof, where the greatest attainment in the accretion of slight modifications was not much more than pond scum, simple eyes gave some living things huge advantages. They could perceive (see is too grandiose a term for those first little devices reacting to not much other than light or shade) things to eat and other things to avoid. From this, says Walker, came the Cambrian proliferation of species 540 million years ago. Because they were now able to exploit many more places to live, millions more animals evolved over this key period in organic history. Seeing was the key breakthrough. It is a sensationally better alternative to not seeing at all. The eye, in its various forms, thereafter evolved separately at least forty times. In squid, octopuses, insects, worms, snails—the creator must have been extremely busy.

Their Own Eyes

...defeat them doubly. First, creationists trot out that old saw about how "nothing as complex as an eye could evolve in stages, since a half-eye is no good at all." Darwin himself trounced that one roundly by merely observing that there are creatures alive today with eyes in all "stages of development," from a few light-sensitive cells, to a cup-shaped receptor with no proper lens, to eagle eyes far sharper than ours. Other creatures seem to get along fine with half-eyes and even 1/100 eyes.

Then for the final insult, human (the pinnacle of creation) eyes are clearly an engineering mistake! The retinas are inside out. The nerves and blood vessels come out through the light-sensitive area of the retina, producing a blind spot, then spread over the front of the light-receptor cells, so that light has to get past the fibers into the receptors. Why aren't the nerves and capillaries behind the receptors, where they would be out of the way and there would be no need for a blind spot? Squid eyes are arranged just that way. Since ours aren't, one is reminded of the maxim that evolution has to work with the materials at hand, adapting systems already in place, with results that often seem jury-rigged or needlessly complicated. Would an Ultimate Engineer make such an obvious blunder, especially having got it right in creatures created earlier?--The Blind Watchmaker, Dawkins, Richard, p., 93

Most kindly,

Sean

Karlis,

I realize that sometimes pages such as wiki can be unsatisfying. Mattshark has a very good point about understanding terminology used and it is one you need to consider if you want to possess the knowledge to discuss these issues.

As I stated in another post, if you want an exact pathway through which evolution happened, then good luck to you. That we will never have. We can find transition fossils, but we can never be 100% certain that one group is the direct ancestral group to another group rather than a split off of the ancestral group and dead branch. This however, does not negate the evidence fossils provide that support phylogeny and nested hierarchies. We can speak on nested hierarchies more if this is something that confuses you.

Right now I would like to take the time to address the eye, however.

As I seem to have become fond of saying, these topics require knowledge –without knowledge this is an object lesson in futility.

That said, lets first cover some basics of the eye. There are main types of eyes. The first type is the positive lens or “camera eye”. This type of eye is found in vertebrates and some invertebrates, it also happens to be the type of eye we possess.


The second type of eye is the simple eye, which we can think of as having two subheadings. Pinhole eyes, found in mollusks and only resolve object location and the concave mirror eye, found in some clams and Ostracods. This eye is capable of bright imagery, low-resolution pictures.

(Note: The eye of the Cyclops is the single red spot).

The third type of eye is the compound eye, made of ommatidia receptors which each function as a visual receptor. Again we have two types of compound eyes: The apposition eye, where the ommatidia function independently. And the Superposition eye, where the ommatidia work in parallel with one another to superimpose images on the retina.


Now that we have our types of eyes, let’s talk for a moment about photoreceptor cells. There are two types of photoreceptors cells, Rhabdomeric and Ciliary. Rhabdomeric cells are found mainly in compound eyes, like that of insects. Ciliary cells, are the type that we humans have as well as other vertebrates. So this is the type I’ll talk mainly about.

Ciliary receptor cells have lots of folds that look like CD’s stacked on one another, this increases surface (which as a quick insert if you are ever unsure of an answer in biology, go with “because it increases surface area”!). This provides more membrane space for the cell to carry out its light sensitive reactions.


So now that you understand some eye basics, we can delve into some eye evolution.

To understand what I am going to talk about, we need to understand a little bit about basic phylogenetics. I am going to make an assumption, that readers of this have a little understanding of phylogenetics, which could get me in to trouble. So if you are having a hard time understanding it, let me know and we can go over some basics.

Today we have many groups with various types of eyes. Looking back in history, we have many fossils that correspond to transitionary eye forms and we have living examples of the branching descendents of these groups.


The long evolution of the eye starts some 600 million years ago, with a new gene that gave rise to light-sensitive pigments that could be incorporated in specialized cells. One can imagine the benefit bequeathed by these pigments. A small mobile organism with the ability to detect light would have been a huge evolutionary advantage and this likely started the arms race of eye evolution.

As I said we have many groups with various developments of the eye alive today. One only needs Google image some of the names above. Let’s focus on vertebrates however.


Above is a simplistic tree taken from a Nature review on vertebrate eye evolution in 2007.

Some 580 million years ago, our last common ancestor with bilaterally symmetrical animals diverged. 530 million years ago animals with skulls appear (craniates). And 500 million years ago, vertebrates show up.

Somewhere between 540 and 500 million years ago (a time during the Cambrain “explosion”), image-forming eyes developed. If we look at the oldest living divergent vertebrate, the lamprey, we see an eye markedly similar to ours. Though we find some glaring differences. Lampreys lack some of the musculature that later vertebrates do. Interestingly, Lamprey larvas have eyes almost identical to that of the hagfish (our outlier).

We see even more evidence in the development of the vertebrate eye when looking at the cellular level.



What we see is a very clear transition in the alignment of photopigment membranes. Leading up to the “CD” stacks we see in our eyes.

We also have molecular evidence to suggest evolution of eyes as well.


Here we see a comparison of opsin genes and key amino acid positions. Note, the center column labeled bovine residue. Similar amino acids are shaded in blue and greens. What we see is this transitionary stepwise change at the amino acid level. It goes from opsins at the top of chart, unused by vertebrates, to ones, which are used. This shows that the molecular components of vertebrate eyes cells were modified from those found in invertebrates.


It appears I am pressed for time, so we will have to conclude here for now. I would recommend some further readings and purchasing the review in Nature. References listed below.

Lamb, D.T., S.P. Collin and E.N. Pugh. 2007. Evolution of the vertebrate eye: opsins, photoreceptors, retina and eye cup. Nature Reviews Neuroscience 8: 960-976

I would also recommend this very interesting study done on the amount of time to evolve a camera type eye.

Nilson, D.E. 1994. A pessimistic estimate of the time required for an eye to e