[extropy-chat] Looking for examples of naturally evolved X-ray vision?

[Alfio Puglisi]

On 1/17/06, BillK <pharos at gmail.com> wrote:

> You need to read up on 'Evolution of Eyes'.  Try:
> <http://www.karger.com/gazette/64/fernald/art_1_0.htm>
> Read a few more as well, to get other opinions.
>
> Basically, he says:
>
>         Why Do We See What We See?
>
>[...]
> Now, five billion years later,

more like five hundred millions years later. Dry land wasn't highly
priced in the real estate market before then.

> though many animal species have moved onto land where
> the sun's full spectrum is available, eyes
> remain sensitive only to this narrow region.

This is incorrect. The full spectrum emitted by the Sun is not
available this side of the atmosphere. See
 http://en.wikipedia.org/wiki/Image:Atmospheric_electromagnetic_transmittance_or_opacity.jpg

for a pretty drawing of atmospheric opacity. Basically, ultraviolet is
quickly absorbed, while infrared fares a bit better.

Alfio