WASHINGTON - Scientists have traced the origin of eyes back to a transparent blob of living jelly floating in the sea about 600 million years ago.
That creature, the distance ancestor of a modern freshwater animal known as a hydra, could only distinguish light from dark.
But that was such an advantage that it was passed on from generation to generation of the hydra's cousins and their myriad descendants. It was the precursor of the wildly different, ever more complex eyes of fish, ants, flies, giraffes, and people.
The hydra work was reported last month in the journal PLoS ONE by biologists David Plachetzki and Todd Oakley, of the University of California, Santa Barbara.
It helps solve one of the puzzles of Darwinian evolution, the process by which a complex organ such as an eye could arise by random genetic mutations and natural selection.
"These results are significant in advancing our understanding of the early evolution of sight in animals," said Jerry Cook, a program director at the National Science Foundation, which financed the work.
In their research, Oakley and Plachetzki discovered that a gene, opsin -- after the Greek word "ops," meaning "eye" -- exists in hydras but not in sponges, an even more primitive animal.
The scientists calculated that the opsin genes appeared about 600 million years ago, because that's when the evolutionary branch that led to modern hydras split from the line that led to sponges.
Opsin genes direct the production of light-sensitive proteins, also called opsins, that coat the surface of a hydra, especially around the mouth. The opsin proteins would help these simple animals tell night from day and perhaps help them find food.
"Hydra probably uses its light sensitivity to find prey," Oakley said.
According to Oakley, the opsin proteins must have evolved from earlier "signaling" proteins that send chemical messages to other proteins. Signaling proteins exist in all living creatures, from single-celled bacteria to humans.
Other biologists commended Oakley's work. "It makes sense that oceangoing animals such as [the hydra's ancestors] would use light detection to orient themselves or regular a body clock," said Sean Carroll, an evolutionary geneticist at the University of Wisconsin, Madison
That is the full text of the article, re-typed by me. If there are errors in it, it was probably my mistake when typing it up.
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Anyway, I thought it was pretty neat that scientists are tracking down the origin of such complex things as eyes. I wonder what other amazing things will be discovered in the future about the past . It's awesome also because hopefully over time we can get rid of some of the creationist bullshit about the difficulty of evolving something like an eye.
Of course the main reason I actually posted the article here rather than just seeing it in the paper and remarking "cool!" to myself was... <img src='http://teamliquid.net/tlpd/images/Zicon_small.gif'>
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Oh, and yes, the journal really is called PLoS ONE, that wasn't some bizarre typo by me.
I don't understand the link between this thing and our eyes (and all other animals yes)..Its a combination of mutliples evolutions or it means this thing was the origin of everything? (the "blob" evolved in fish and so..)
It helps solve one of the puzzles of Darwinian evolution, the process by which a complex organ such as an eye could arise by random genetic mutations and natural selection.
I dont see how finding an extinct creature that could see light from dark explains the process of the evolution of the eye. The whole problem that people have with the evolution of the eye is that it is so amazingly complex, and there are many peices to the eye that would not evolve on their own; the eye would have to evolve all at once in order for it to work.
So this just says: hey heres something that can sense light and dark, and 600 million years later BAM! we got eyes! Its SCIENCE!!!
This isn't to say I don't beleive in evolution (I do believe to some extent). But they are leaving out many important steps in the evolution of the eye (i.e. the part where we actually evolve one).
It helps solve one of the puzzles of Darwinian evolution, the process by which a complex organ such as an eye could arise by random genetic mutations and natural selection.
I dont see how finding an extinct creature that could see light from dark explains the process of the evolution of the eye. The whole problem that people have with the evolution of the eye is that it is so amazingly complex, and there are many peices to the eye that would not evolve on their own; the eye would have to evolve all at once in order for it to work.
So this just says: hey heres something that can sense light and dark, and 600 million years later BAM! we got eyes! Its SCIENCE!!!
This isn't to say I don't beleive in evolution (I do believe to some extent). But they are leaving out many important steps in the evolution of the eye (i.e. the part where we actually evolve one).
Wow, how can you miss such a simple point? The "hydra" could see without a complex eye, showing that rudimentary sight was possible with only light-sensitive proteins.
So your saying because we haven't found every single mutation and step along the 600 million years, it must have just magically formed an eye? - obviously not. The simple eye will randomly mutate, and maybe that mutation will help it to see better, thus allowing it to survive. In a huge number of very small steps, the complex eye we have today formed, and just because we haven't documented what each step is, that doesn't disprove anything.
It's the same thing with all creationists, they lack a basic understanding of how evolution works.
It helps solve one of the puzzles of Darwinian evolution, the process by which a complex organ such as an eye could arise by random genetic mutations and natural selection.
I dont see how finding an extinct creature that could see light from dark explains the process of the evolution of the eye. The whole problem that people have with the evolution of the eye is that it is so amazingly complex, and there are many peices to the eye that would not evolve on their own; the eye would have to evolve all at once in order for it to work.
So this just says: hey heres something that can sense light and dark, and 600 million years later BAM! we got eyes! Its SCIENCE!!!
This isn't to say I don't beleive in evolution (I do believe to some extent). But they are leaving out many important steps in the evolution of the eye (i.e. the part where we actually evolve one).
On November 09 2007 07:07 Steelflight-Rx wrote: The whole problem that people have with the evolution of the eye is that it is so amazingly complex, and there are many peices to the eye that would not evolve on their own; the eye would have to evolve all at once in order for it to work.
Except that here you have that very thing. A piece of modern eyes that is evolving without the full eye, and being so useful that it sticks around and spreads like crazy.
There's an expression that runs: "In the kingdom of the blind, the one-eyed man is king." The thing about eyes is that you only have to see better than everything else can see and you have an advantage. It doesn't have to give you vision in the sense we think of it today. It just gets better and better gradually, in tiny little steps, and then you end up with an eye.
I'm sure that now they've found this end of the "string", they'll be able to follow it and trace the evolution of other components of modern eyes as well.
It was the same with legs, and spines, and many other features we ended up with in modern-day land animals, including humans. They started off really basic, and not obviously useful compared to what we have now, but back then they were a big deal to the creatures that had them.
I just wanted to second how wrong Steelflight-RX is. And steelflight, if you're going to dismiss the biologists work, you should at least know exactly what they did. One breif news paper article is NOT going to tell you the scope of their research. You need to actually read the scientific paper they published before you can say "So this just says: hey heres something that can sense light and dark, and 600 million years later BAM! we got eyes! Its SCIENCE!!!" Do you really think you can get the full story from a simple newspaper article? You should know better than that.
Also I wanted to add: unfortunately creationists will dismiss the research or just ignore it completely and continue to use the human eye as "proof against evolution." Sad=/
It doesn't matter if the human eye will ever be understood. We don't need to ever understand how evolution could create an eye to believe it over other simply lesser theories. If i was to turn to the idea that god must've created the eye if it was proven that evolution didn't, tell me what logic i would be following? I'd be following the logic that god having created the eye is a reasonable assumption, because there is no better explanation, which might then lead me to search out god. In a world where evolution is a theory without an as of yet perfect array of evidence to back it up, but is still highly plausible, and scientifically there is no reason to believe god exists, that is the same reason evolutionists believe what they do.
I think i might rather read about science articles like this from a scientific magazine so that i know it's not just utter crap on a popular theme, without as necessarily reading the sources and stuff. Seatle times publishes a hugely vague article claiming that the eye's origins have been traced, according to one some guy scientist?
On November 09 2007 09:15 Rev0lution wrote: who says evolution makes you not believe in god? I have tons of christian friends who believe in evolution.
people can say whatever crap comes to their heads, but this does not make the things they say right.
for example: a) you need wings to fly. b) people can't fly because they don't have wings c)someone comes and tells you "I'm a human, but I can fly"
the example kind of sucks, but I hope you get my point.
haha, go to around 23:00 minutes in it says "Evolution and Origin of the eye is likely to remain unsolved!"
~Ouch
I dont see any proof for their claims about the hydra, all just speculation. i will not post anymore im starting to get tired about this discussions. glhf 8/
haha, go to around 23:00 minutes in it says "Evolution and Origin of the eye is likely to remain unsolved!"
~Ouch
I dont see any proof for their claims about the hydra, all just speculation. i will not post anymore im starting to get tired about this discussions. glhf 8/
Try reading their paper then. Of course you won't see any proof for their claims if you don't even look.
This is for those who actually want to read it. Although I must warn you if you arent very framiliar with biology/organic chemistry it's a very tough read
Oh and TesisMech,I'd hate to be condescending (ok not that much ) but seeing as you flat out deny the existance of evolution I'm pretty sure it will be way over your head. However, maybe you could take a look at the enormous complexity of the work they are doing and realize that its far more than simply "specuation". Perhaps you are unaware of the scentific method? Its actually the exact opposite of speculation. If you insist on being ignorant, at least keep quiet about it.
Hydra. They are really fun creatures to feed, I had a jarfull once upon a time, it was an interesting experience.
Really? How do you take care of them? They're probably different from taking care of fish right? I totally want to have a jar of hydras, so whenever my friends piss me off in SC I can open a can of Hydra on their ass, so to speak.
EPT
. It's awesome also because hopefully over time we can get rid of some of the creationist bullshit about the difficulty of evolving something like an eye. ![[image loading]](http://teamliquid.net/tlpd/images/Zicon_small.gif)
![[image loading]](http://www.micrographia.com/specbiol/cnidari/hydrozo/hydr0100/hydra-01.jpg)
