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

[kevinfreels.com]

I was helping my daughter come up with some ideas for a school science project and I stumbled onto a couple unknowns.

Animals have evolved a wide variety of abilities to seek food and avoid predators. Echo-location, color vision, and compound eyes are just a few. All provide important information regarding the immediate surroundings. My daughter asked me why the visible light spectrum IS the visible light spectrum. After all, animals hear at a wide range of frequencies that humans cannot, so why not have the same thing occurring in vision? Are there animals with X-ray vision?

My first reaction was to say "no". After all, once you leave the visible spectrum, light becomes considerable less usefull to the purposes of survival. For example, what good is an X-ray if you see right through the animal that is hunting you? I guess a predator that was invisible to visible light but detectable by X-rays would do the trick, but such a thing is impossible (except for some high-tech cloaking and imaging system). I could think of no reason that X-ray vision would be selected for. Of course, there is random chance, but eyes and the brain's ability to interpret what it is seeing are tough developments to attribute to chance.

So I started to look for information on this. According to a small atricle in Wikipedia (http://en.wikipedia.org/wiki/Roentgen_Rays), Brandes and Roentgen discovered that X-rays ARE visible to the dark adapted human naked eye. I really did not know this although I am sure some of you were aware of it. 

Now I am wondering if anyone knows any examples of a natural biological organism that has developed and improved upon the abillity to see X-rays. Google has turned up nearly blank. And if the ability is there, how could it be built upon and used as we take evolution into our own hands? 


 
 
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