How Did Eyeballs Evolve?

[wayfriend]

So which came first, the chicken organism afraid of the dark, or the eye-spot?

Neurotransmitters, moving the signal from the receptor to the brain.

But what good are neurotransmitters without something to transmit? What of any evolutionary advantage would be that first step?

And what good are neurotransmitters transmitting photoreceptic information without being able to react to it? What of any evolutionary advantage would be that next step?

Eyes may not be irreducibly complex. But awareness seems to be.

[Hashi Lebwohl]

This is incorrect. Green plants are green, as I originally said, because those are exactly the wavelengths that are useless for their needs.

In a sense, yes. Chlorophyll re-emits green light because it doesn't need it, so leaves appear to us as green. That chemical's composition makes it a very efficient absorber of yellow light.

That's what we're discussing wayfriend. Clearly, being able to see has tons of advantages over not being able to see for animals so we were looking into the "how" of eyes.

[Vraith]

That's what we're discussing wayfriend. Clearly, being able to see has tons of advantages over not being able to see for animals so we were looking into the "how" of eyes.[/color]

Here's the part that I can't wrap my head around [perhaps cuz I simply don't know the root knowledge]. I get how eyes could evolve, its just energy and chemistry, no matter how complicated [and lets not forgot it took a long damn time and had unfathomable numbers of opportunities to happen]...I get how awareness could happen from that too. I understand how proteins, unimaginable numbers of them, could arise from a simple soup of very basic elements and energy. [I don't know all, or even most of the precise steps involved, but I know enough of the basic rules to see generically how it could happen].
I don't get how/why the step happens from a protein that arose purely through chemistry to a protein that "collects" energy and "gathers" the elements necessary to copy itself. Once that step is accounted for, everything else seems simple [in the most complicated possible definition of simple].

[wayfriend]

Hashi, if I understand what you mean, it's not the eye per se, but the whole system which includes perception, cognition, and reaction as a whole whose origins perpexes you. Is this it?

Vraith: yes, the whole concept of how DNA evolved is unimaginable. Inheritance is the engine of evolution ... so how could it itself evolve?

[Hashi Lebwohl]

Hashi, if I understand what you mean, it's not the eye per se, but the whole system which includes perception, cognition, and reaction as a whole whose origins perpexes you. Is this it?

Well, my original question was really an attempt to figure out how an eyeball could have formed. At some point there are living beings without eyes and then there are, so at some point cells became sepecialized with the ability to detect and respond to photons of visible light. Fascinating stuff.

Vraith, now I need to go back and find the article I saw last week (or was it two weeks ago?) about the team trying to put together "living" cells built only from inorganic compounds.
According to the science, it appears that self-replication is a side-effect of the DNA proteins. If we build DNA from scratch in a lab, it should begin replicating simply because that is what happens when those protein chains exist.

[Vraith]

Vraith, now I need to go back and find the article I saw last week (or was it two weeks ago?) about the team trying to put together "living" cells built only from inorganic compounds.
According to the science, it appears that self-replication is a side-effect of the DNA proteins. If we build DNA from scratch in a lab, it should begin replicating simply because that is what happens when those protein chains exist.[/color]

I might have seen at least a summary/headline about that...I know I didn't see the whole thing.
I did see about a year [or two?] ago about the first guy to experiment with just elements and energy to make organic entities that they thought had failed...but now [30 or 40 years later] they discovered that it actually HAD worked.
I'd love to see that article, if it has even a hint of how/why.
You're original question is still part of it, certainly. It makes perfect sense to me that atoms/molecules/cells can detect light. Meaningful response is the hard part....though I suppose if almost all detect them, then with umpteen million different responses possible, the randomly correct choice would then have an advantage once we solve the replication thing.