>From: Lars Henrik Mathiesen <[log in to unmask]> > >I read an anecdote about an astrophysicist who had the lenses in his >eyes removed/replaced (for some medical reason). It turns out that >it's the lenses that filter out the low UV part of the spectrum --- >the blue cones readily detect it, so he was suddenly able to see well >beyond purple in the spectrum. (And, I'm guessing, was likely at risk >of his retinas burning out if he lived in a sunny climate --- there's >bound to be an evolutionary tradeoff between the utility of seeing >extra details in nature, and keeping your eyesight all life). > >The source I read didn't go into stuff like how many different colours >he perceived in the new wavelengths, or how much it changed the look >of everyday objects --- more that his colleagues though it was neat >how he could calibrate their UV spectrometers without a photometer. > >Lars Mathiesen (U of Copenhagen CS Dep) <[log in to unmask]> (Humour NOT >marked) I imagine this "oversight" <groans welcome> of nature is only because there really isn't much utility in seeing UV for primates - given the typical primate diet and the normal environmental threats to our safety. I'm guessing we probably only have colour vision at all because our ancestors lived in trees and were active during the day (thus well developed nightvision and sense of smell were less important)... What is truly fascinating though is that our blue cones can detect UV even after all these generations of living with optic lenses that filter it out... it suggests that there is only a limited number of ways to produce a biological mechanism that can detect blue light - I feel just a tad closer to kinship with bumble-bees now... Andy _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp.