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Comment by dekhn | Hacker News Reader

The ratchet is a the simplest universal physical mechanism that seems to fall out of physics into chemistry and biology all the time.

eyes are a bit more subtle. It would be really interesting to know the specific trajectories of evolution that led to the formation of sensitive pigments (probably the earliest vision systems), through the development of lenses, etc.

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You can see a fair bit in the Cephalopod order, from the Nautilus (https://en.m.wikipedia.org/wiki/Chambered_nautilus) which has no lens, the Cuttlefish with monochromatic vision through to the Octopus.

It's interesting to observe the differences, cephalopods don't have blind spots and can perceive polarised light.

I'd rather see the actual historical events that happened (like a movie made by a time machine) rather than reconstructions from extant organisms and fossils.

BTW, humans can kinda see polarized light (https://en.wikipedia.org/wiki/Haidinger%27s_brush).

Interestingly, cuttlefish have monochromatic vision but their camouflage matches the color of their surroundings. Presumably, they get the color signal through color-capable receptors in their skin.

Cuttlefish are weirder than that, the current theory is their W-shaped pupil causes chromatic aberration on the retina and they can use that to detect colour.

http://news.berkeley.edu/2016/07/05/weird-pupils-let-octopus...

Wow! I wonder if we could we potentially infer color from black & white photos of celestial objects, by this technique? Maybe it could be combined with the adaptive optics that attempt to cancel stuff like this?

you can already do similar things with filters, you don't need any exotic biology to do it.

But filters block light, reducing the effectiveness of the telescope. Also, you need to set them up before the photos are taken. I am suggesting a way to process existing grayscale photos, where the operator may have decided that filters weren't worth diminishing the captured light, or the increase in communications bandwidth.

Hmm, I'm skeptical. Beyond meaning they'd need to be reclassified as color-vision with a unique mechanism (in itself interesting), it doesn't really address how the camouflage on the top of the squid matches what's below in (where its eyes can't see).

BTW: a press release and Science paper is not "the current theory".

The Blind Watchmaker discusses the physical evolution of the eye. Here's a video:

http://www.dailymotion.com/video/x3lstd5

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