Any engineer would naturally assume that the photocells would point towards the light, with their wires leading backwards towards the brain. He would laugh at any suggestion that the photocells might point away from the light, with their wires departing on the side nearest the light. Yet this is exactly what happens in all vertebrate eyes. Each photocell is, in effect, wired in backwards, with its wires sticking out on the side nearest to the light. This means that the light, instead of being granted an unrestricted passage to the photocells, has to pass through a forest of connecting wires, presumably suffering at least some attenuation and distortion
Blindguide: Richard Dawkins
http://en.wikipedia.org/wiki/The_Blind_Watchmaker
Tuesday, May 29, 2007
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