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

Acy Stapp acy.stapp at gmail.com
Thu Jan 19 21:10:08 UTC 2006


Is there any evidence that THz radiation can be perceived by animals?
It seems physiologically feasible (and evolutionarily useful) but
AFAIK the only ambient source of THz radiation is blackbody emission.

Acy

On 1/18/06, Dirk Bruere <dirk.bruere at gmail.com> wrote:
>
>
>
> 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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--
Acy Stapp

"When I'm working on a problem, I never think about beauty. I think
only how to solve the problem. But when I have finished, if the
solution is not beautiful, I know it is wrong." -- R. Buckminster
Fuller (1895 - 1983)



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