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Author Topic:   Evolution of Eyes
Equinox
Member (Idle past 5141 days)
Posts: 329
From: Michigan
Joined: 08-18-2006


Message 31 of 52 (460026)
03-12-2008 7:06 AM
Reply to: Message 18 by Lyston
03-11-2008 7:51 PM


Which Bodily Secretion?
Lyston wrote:
How would the fluid start to secrete? You said it would start automatically due to normal growth. Are you saying that it would be something like trapped embryo fluid or something like that inside? Or are you saying that something will secrete the fluid into the space?
Rahvin gave a plausible answer, but like you, I was seeing trapped (something like) amniotic fluid inside. Before hatching or whatever, the whole organism is in some fluid, and so that cavity wouldn't somehow be air filled to start with.
During growth, I'd expect that fluid to be changed as circulation took out some things and put other things in. Rahvin's "filling" method works too, but I'd guess that our (Lyston & I's) embryonic method is more likely.
Of course, fluids (and their chemical composition) fossilize even worse than soft eyes, so there's little fossil evidence. However, there probably are extant animals with eyes like d, does anyone know how their eye fluid progresses over thier lives?
I guess any of multiple routes would work, but I at least don't know which one happened in each eye lineage. Could be (probably is) that different routes are what happened in say, vertebrate eyes, vs. cephalopod eyes, etc.
Have a fun day-
Equinox

This message is a reply to:
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Replies to this message:
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molbiogirl
Member (Idle past 2641 days)
Posts: 1909
From: MO
Joined: 06-06-2007


Message 32 of 52 (460054)
03-12-2008 12:46 PM
Reply to: Message 31 by Equinox
03-12-2008 7:06 AM


Re: Which Bodily Secretion?
However, there probably are extant animals with eyes like d, does anyone know how their eye fluid progresses over their lives?
The fluid doesn't "fill" an empty socket.
Two tissue layers form. When the two layers separate, an aqueous humour fills the gap.
The transparent cells over the pinhole eye's aperture split into two layers, with liquid in between. The liquid originally served as a circulatory fluid for oxygen, nutrients, wastes, and immune functions, allowing greater total thickness and higher mechanical protection. In addition, multiple interfaces between solids and liquids increase optical power, allowing wider viewing angles and greater imaging resolution. Again, the division of layers may have originated with the shedding of skin; intracellular fluid may infill naturally depending on layer depth.
Again. Lys. A little effort on your part (like reading the links we provide) will go a long way.
Edited by molbiogirl, : wiki quote

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Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 33 of 52 (460117)
03-12-2008 8:17 PM
Reply to: Message 8 by Lyston
03-08-2008 4:49 PM


Close, but no. More of, from what I understand from the pamphlet "That was pretty complex for back then, seeing as organisms still have such a structure."
And the sheer depth of confusion that that exhibits makes it hard to answer.
How complex should structures have been back in the Cambrian? Why should a successful structure be removed from living organisms? How?
I can see that the person who wrote your pamphlet is making some collosal mistake, but he's not even specific enough to say what mistake he's making.
It's like trying to punch a fog.
If you will hazard a guess at what point he was trying to prove, I shall explain why he's wrong.
Imagine that you were an expert in physics, and someone came up to you and said "Gold weighs more than it should, and this disproves the theory of gravity", then you'd want to ask him a few questions, like how much should gold weigh, and what the heck he thinks the theory of gravity is, and how it bears on the weight of gold.
I think that a lot of people trying to answer this question have misunderstood it. But this is not to their blame --- what the heck is there in that question that they should have understood?
Edited by Dr Adequate, : No reason given.

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Replies to this message:
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Granny Magda
Member
Posts: 2462
From: UK
Joined: 11-12-2007
Member Rating: 4.0


Message 34 of 52 (460127)
03-12-2008 9:56 PM
Reply to: Message 33 by Dr Adequate
03-12-2008 8:17 PM


Hi Doc,
What you say about confusion being generated by the terms laid out in Lyston's pamphlet is a good point. Here it is again, for reference;
some creationist writes:
The Trilobite Eye.
Millions of Trilobites exist in ancient Cambrian rock. These Trilobites have eyes that are as complex as any eyes that exist today. This fossil fact (and thousands others) falsifies the Theory of Evolution by complex systems appearing suddenly without any transitions.
It sounds to me as though it's argument is "Look! A gap in the fossil record! That proves the whole of evolutionary theory wrong.", a familiar piece of nonsense.
I think that it would be helpful if Lyston were to post a bit more from this pamphlet, the whole thing if it's at all practical.

Mutate and Survive

This message is a reply to:
 Message 33 by Dr Adequate, posted 03-12-2008 8:17 PM Dr Adequate has not replied

Replies to this message:
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molbiogirl
Member (Idle past 2641 days)
Posts: 1909
From: MO
Joined: 06-06-2007


Message 35 of 52 (460145)
03-12-2008 11:47 PM
Reply to: Message 34 by Granny Magda
03-12-2008 9:56 PM


I think that it would be helpful if Lyston were to post a bit more from this pamphlet, the whole thing if it's at all practical.
Be even better if he posted a link.
I googled his quote and came up with nada.
Instead, I found this:
"But if we look at the individual elements of the trilobite eye, we find that the lens systems were very different from what we now have. Riccardo Levi-Setti (a Field Museum research associate in geology and professor of physics at the University of Chicago) has recently done some spectacular work on the optics of these lens systems. Figure 7 shows sketches of a common type of trilobite lens. Each lens is a doublet (that is, made up of two lenses. The lower lens is shaded in these sketches and the upper one is blank. The shape of the boundary between the two lenses is unlike any now in use either by humans or animals. But the shape is nearly identical to designs published independently by Descartes and Huygens in the seventeenth century. The Descartes and Huygens designs had the purpose of avoiding spherical aberration and were what is known as aplanatic lenses. The only significant difference between them and the trilobite lens is that the Descartes and Huygens lenses were not doublets - that is, they did not have the lower lens. But, as Levi-Setti has shown, for these designs to work underwater where the trilobite lived, the lower lens was necessary. Thus, the trilobites 450 million years ago used an optimal design which would require a well trained and imaginative optical engineer to develop today-or one who was familiar with the seventeenth century optical literature." (Raup D.M., "Conflicts Between Darwin and Paleontology," Field Museum of Natural History Bulletin, Field Museum of Natural History: Chicago IL, January 1979, Vol. 50, No. 1, pp.22-29, p.24).
iiNet | naked dsl - broadband - adsl - phone - voip

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Replies to this message:
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AnswersInGenitals
Member (Idle past 150 days)
Posts: 673
Joined: 07-20-2006


Message 36 of 52 (460405)
03-14-2008 7:05 PM
Reply to: Message 35 by molbiogirl
03-12-2008 11:47 PM


Mammalian eyes are doublets.
The human eye (as with all mammals) is a doublet. The cornea actually provides most of the eye's optical power. The lens performs some focusing, but unlike the fixed cornea, is flexible and allows for adjustable focusing.

This message is a reply to:
 Message 35 by molbiogirl, posted 03-12-2008 11:47 PM molbiogirl has replied

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molbiogirl
Member (Idle past 2641 days)
Posts: 1909
From: MO
Joined: 06-06-2007


Message 37 of 52 (460411)
03-14-2008 8:51 PM
Reply to: Message 36 by AnswersInGenitals
03-14-2008 7:05 PM


Re: Mammalian eyes are doublets.
AIG ...
I mentioned the differences between trilobite and brittlestar eyes earlier. (Some creo thought they were "the same thing".) That's why I highlighted that passage.
ABE:
In other words, the creos can't get their stories straight.
Edited by molbiogirl, : No reason given.

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Lyston
Member (Idle past 5825 days)
Posts: 64
From: Anon
Joined: 02-27-2008


Message 38 of 52 (460442)
03-15-2008 2:13 AM


Alright, I must say that I am sorry for not spending more time here. I've been very, very busy, trying to juggle around my priorities the best I could, and this got moved to second to last. I have read through most of this, with (as molbiogirl said) the exception of most links.
If you have something that you would like for me to directly address, reply to this exact message and I will give my best answer ASAP. I will be in this rush until Mid-July, so again, I am sorry.
For now, I will say (for the pamphlet comments) that I am sure you won't find the pamphlet on the internet. It was handed to me by a creationist, and I happened to have read through it (honestly, it was that pamphlet that led me to search for an EvC website). You will not find more about what it says on the eyes even if you were holding the thing. It's called "Six Things Evolutionists Do Not Want You To Know" with 'The Trilobite Eye' being number 5. I would need a new thread to post the other topics mentioned in it. I wouldn't withhold information from you. I'm here for answers, not to prove a point.
Again, if you have something you want me to address, reply to this message. I will, however, read the other messages whenever possible (so don't think I'm ignoring them), but if you want me to answer a specific question, tell me.

Replies to this message:
 Message 39 by Dr Adequate, posted 03-15-2008 5:21 AM Lyston has replied

  
Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 39 of 52 (460446)
03-15-2008 5:21 AM
Reply to: Message 38 by Lyston
03-15-2008 2:13 AM


You will not find more about what it says on the eyes even if you were holding the thing. It's called "Six Things Evolutionists Do Not Want You To Know" with 'The Trilobite Eye' being number 5.
And this sort of rhetoric is singularly dishonest.
The only reason creationists know anything about trilobites the fossil record is because "evolutionists", specifically paleontologists, have spent a lot of time and effort studying trilobites and have published their results. He wouldn't know what a trilobite was if it wasn't for the "evolutionists" he whines about. And then the ungrateful shit has the nerve to sit on his fat idle arse and moan about how evolutionists "don't want you to know" about trilobites.
Funny how they appear in every sodding book about the history of evolution, then, isn't it?
I don't suppose he mentions how the earliest trilobites are eyeless, does he? We evolutionists would like you to know that, too.

This message is a reply to:
 Message 38 by Lyston, posted 03-15-2008 2:13 AM Lyston has replied

Replies to this message:
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Lyston
Member (Idle past 5825 days)
Posts: 64
From: Anon
Joined: 02-27-2008


Message 40 of 52 (460675)
03-17-2008 9:15 PM
Reply to: Message 39 by Dr Adequate
03-15-2008 5:21 AM


I don't suppose he mentions how the earliest trilobites are eyeless, does he? We evolutionists would like you to know that, too.
I actually already knew that from reading the wikipedia article. But, this brings up a new question for me. From between the early eyeless and the more complex-eyed trilobites, are there any signs of the "in between"? I'm not saying "gap means wrong", but I'm sure that their should be some signs of the in between if they have found both eyeless and more complex-eyed in a million(?) year gap.
If someone could post a link that discusses this, it would be much appreciated.

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 Message 39 by Dr Adequate, posted 03-15-2008 5:21 AM Dr Adequate has not replied

Replies to this message:
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molbiogirl
Member (Idle past 2641 days)
Posts: 1909
From: MO
Joined: 06-06-2007


Message 41 of 52 (460679)
03-17-2008 11:16 PM
Reply to: Message 40 by Lyston
03-17-2008 9:15 PM


Lyston,
Did it ever occur to you to google "trilobite eye evolution"?
The first hit.
The Trilobite Eye

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TheWay
Junior Member (Idle past 5844 days)
Posts: 27
From: Oklahoma City, Ok
Joined: 08-21-2007


Message 42 of 52 (461764)
03-27-2008 5:48 PM
Reply to: Message 16 by Equinox
03-11-2008 12:37 PM


So easy a caveman could do it...
Unfortunately your hypothetical 'just so' story didn't involve enough reality to keep my interest. Use more action and drama next time.
Eye evolution was recognized as easy even 150 years ago - Darwin described the process in post #9, long before we found living transitional forms of so may intermediate steps.
I take special issue with this form of guile. If I take common descent as prescribed, I would never use the word "easy" to describe millions of years of change. A remote control for television is a device that could be used to denote "easy." I would like you to elaborate on these transitional forms, and be specific please. I am currently researching the topic of transitional forms and transitional eyes would be greatly appreciated.
Thanks.

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Replies to this message:
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 Message 44 by Blue Jay, posted 03-27-2008 6:23 PM TheWay has not replied
 Message 45 by Dr Adequate, posted 03-29-2008 12:45 AM TheWay has not replied

  
molbiogirl
Member (Idle past 2641 days)
Posts: 1909
From: MO
Joined: 06-06-2007


Message 43 of 52 (461766)
03-27-2008 6:05 PM
Reply to: Message 42 by TheWay
03-27-2008 5:48 PM


I would like you to elaborate on these transitional forms, and be specific please. I am currently researching the topic of transitional forms and transitional eyes would be greatly appreciated.
I suggest you do your own homework.
This very point has been covered at least 3 times in this thread alone.
If, after having read the thread, you have any specific questions about a particular aspect of "transitional" forms, I would be more than happy to answer them.

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 Message 42 by TheWay, posted 03-27-2008 5:48 PM TheWay has not replied

  
Blue Jay
Member (Idle past 2697 days)
Posts: 2843
From: You couldn't pronounce it with your mouthparts
Joined: 02-04-2008


Message 44 of 52 (461769)
03-27-2008 6:23 PM
Reply to: Message 42 by TheWay
03-27-2008 5:48 PM


Re: So easy a caveman could do it...
TheWay writes:
I am currently researching the topic of transitional forms and transitional eyes would be greatly appreciated.
In Message #30, I provided this link (Encyclopedia Britannica article about mollusc eye evolution). It contains a set of diagrams that represent the ocular structures of five living types of molluscs.
Note: limpets, slit-shells and snails are all members of the order Gastropoda ("stomach-foot molluscs), and Nautilus is in the order Cephalopoda ("head-foot molluscs"), along with squids and octopus, an order which is generally considered to have evolved from Gastropoda.
Granted, these pictures don't represent transitional forms per se (seeing how they're all alive today), but they do demonstrate very well the gradient from simple clusters of light-sensitive pigment cells to complex, enclosed eyes with lenses, etc. within a single monophyletic group. This is also given in conjunction with several genetics and taxonomic studies and fragments of the fossil record (mostly shells, which fossilize quite well) of gastropods and cephalopods. So, there is a decent set of backing evidence for the hypothetical scenario that Equinox put forth.

There was a point to this [post], but it has temporarily escaped the chronicler's mind. -modified from Life, the Universe and Everything, Douglas Adams

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Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 45 of 52 (461975)
03-29-2008 12:45 AM
Reply to: Message 42 by TheWay
03-27-2008 5:48 PM


Re: So easy a caveman could do it...
Unfortunately your hypothetical 'just so' story didn't involve enough reality to keep my interest. Use more action and drama next time.
If you find science boring, could I suggest that you take up a less demanding hobby?
I take special issue with this form of guile. If I take common descent as prescribed, I would never use the word "easy" to describe millions of years of change. A remote control for television is a device that could be used to denote "easy."
Your ability to wilfully misinterpret what other people are saying to you is not evidence of their "guile", but your own.
I would like you to elaborate on these transitional forms, and be specific please. I am currently researching the topic of transitional forms and transitional eyes would be greatly appreciated.
The Molluscae display all the intermediate forms in what you describe as a "hypothetical just-so story".
---
Would you like to elaborate on how God made eyes by magic? No, thought not.
Creationists don't get to whine about "just-so stories", pal. 'Cos that's all you've got. God just said it should be so, and it just was so.

This message is a reply to:
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