[extropy-chat] FWD [forteana] Re: Looking for examples of naturally evolved X-ray vision?

[Dirk Bruere]

On 1/19/06, Terry W. Colvin <fortean1 at mindspring.com> wrote:
>
> 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
> blocked.
> 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
> substitute)
>
> 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.



Which leaves mm wavelength radiation.

Dirk
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