First eyes appeared 700 million years ago

[klr]

http://www.theregister.co.uk/2012/10/30 ... _of_sight/

First eyes EVER SEEN (by definition) appeared 700 million years ago

Here's looking at you, jellyfish

By Brid-Aine Parnell • Get more from this author
Posted in Science, 30th October 2012 14:29 GMT

Animals were seeing stuff a lot earlier than previously thought, a new study suggests.

When exactly the ability to see evolved in animals has been hotly contested among boffins, but researchers from Bristol and Maynooth universities reckon a group of marine animals first "saw" the light 700 million years ago.

Using computer modelling, the scientists figured out how and when opsins evolved in a group of marine animals including jellyfish, which are considered to have had the world's earliest eyes. Opsins are the protein receptors which confer the ability to sense light in all animals that have had sight throughout time.

The program used data from every hypothesis of opsin evolution to date as well as all the available genomic information from a recently discovered group of sponges called Oscarella carmela and Cnidarians, or jellyfish.

The team, from Bristol Uni's School of Earth Sciences and National University of Ireland Maynooth, now reckon that an opsin ancestor common to all the group started showing up 700 million years ago. That opsin was 'blind' but over the next 11 million years it evolved genetically to allow it to detect light.

"The great relevance of our study is that we traced the earliest origin of vision and we found that it originated only once in animals," Dr Davide Pisani of Bristol said. "This is an astonishing discovery because it implies that our study uncovered, in consequence, how and when vision evolved in humans."

The study was published in the Proceedings of the National Academy of Sciences (PNAS). ®

[Gawdzilla Sama]

"So, those eyes just POPPED into existence?" /fundie.

Interesting that eyes are a one-off, and we might not have them. I'm sure animals would have developed "something else" if eyes weren't available. I wonder what that would have been?

[klr]

Cue for one of the great Darwin quotes out of context:

To suppose that the eye, with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection, seems, I freely confess, absurd in the highest possible degree.

The cretinists omit the next bit:

Yet reason tells me, that if numerous gradations from a perfect and complex eye to one very imperfect and simple, each grade being useful to its possessor, can be shown to exist; if further, the eye does vary ever so slightly, and the variations be inherited, which is certainly the case; and if any variation or modification in the organ be ever useful to an animal under changing conditions of life, then the difficulty of believing that a perfect and complex eye could be formed by natural selection, though insuperable by our imagination, can hardly be considered real. How a nerve comes to be sensitive to light, hardly concerns us more than how life itself first originated; but I may remark that several facts make me suspect that any sensitive nerve may be rendered sensitive to light, and likewise to those coarser vibrations of the air which produce sound.

Maybe they just don't like long sentences ...

[Gawdzilla Sama]

No, they lie.

[Tero]

What's interesting about mammal and other eyes is that they connect directly to the brain. It does not go through the spinal cord. Yet the light sensitive spots were on the skin. Like in planaria.

[odysseus]

"So, those eyes just POPPED into existence?" /fundie.

Interesting that eyes are a one-off, and we might not have them. I'm sure animals would have developed "something else" if eyes weren't available. I wonder what that would have been?

I always thought that the eye evolved independently in many different lineages, but a quick search suggests that it was lenses that did that. I need to read more into this....

[Rum]

It isn't complicated. God did it.

[odysseus]

It isn't complicated. God did it.

Yes. Yes. Sorry....

[Horwood Beer-Master]

"So, those eyes just POPPED into existence?" /fundie.

Interesting that eyes are a one-off, and we might not have them. I'm sure animals would have developed "something else" if eyes weren't available. I wonder what that would have been?

I'm pretty certain animals on this planet would have developed eyes.

[JimC]

In reality, the research is not about the first eyes, but about the first light detecting cells, and the pigments that allowed this to occur...

[Berthold]

What's interesting about mammal and other eyes is that they connect directly to the brain. It does not go through the spinal cord. Yet the light sensitive spots were on the skin. Like in planaria.

Well, the epidermis as well as the nervous system are derived from the ectoderm, if I remember my school biology correctly.