[extropy-chat] FWD [forteana] Re: Looking for examples of naturally evolved X-ray vision?
Terry W. Colvin
fortean1 at mindspring.com
Thu Jan 19 03:09:48 UTC 2006
On 1/18/06, Terry W. Colvin <fortean1 at mindspring.com> fnarded:
> 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?
Several reasons why not:
1. Animals don't generate the light they see by, by and large, they detect
light generated by the sun or by other animals.
2. Therefore the light that is used to see by must be something that is
reflected by the things you want to see.
3. X-rays mostly go right through things you might want to see. Infrared is
mostly absorbed by them.
4 Given that early life evolved in water, the visible spectrum is the about
the only bit *not* blocked by atmosphere plus water. IR, X-rays, Radio, and
UV are all blocked by water. Not much point seeing a frequency which is
5. X-rays are extremely energetic, and actually break down biological
tissue; hard to make a biological detector.
6. X-rays are extremely energetic, and would be hard or impossible for
living systems to generate.
Certain animals (e.g. Snakes) can "see" infra-red (Humans can detect IR, too
- just stand near a fire.....)
Certain animals (e.g. Bees) can "see" UV (I believe that humans can see near
UV if the lens of the eye has been removed or replaced by a synthetic
Radio waves certainly reach earth,and I suppose could be a good thing to see
by, except that they are faint, and receiving them requires rather large
receivers, probably not practical for biological systems. They are also
absorbed, rather than reflected by lots of things.
Excellent question, though.
"Only a zit on the wart on the heinie of progress." Copyright 1992, Frank Rice
Terry W. Colvin, Sierra Vista, Arizona (USA) < fortean1 at mindspring.com >
Alternate: < fortean1 at msn.com >
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