Re: [KV] Colors (was Re: Movies)

On Fri, 27 Jul 2001 10:17:15 +1000, Beth Fulton
<beth.fulton@marine.csiro.au>
wrote:

>>OTOH, they may be colour blind (like cats).
>
>Cats aren't strictly "colour blind" they do retain a few cones, though
have 
>sacrificed a lot for good movement and night vision. They probably
actually 
>see in pale with the definition getting better the closer they get.

Just as dogs aren't colour blind, either.

Another thing could be the placement of the point where the optic nerve
attaches to the retina (assuming a similar structure to humans). This
point
creates a blind spot. It's fairly easy to find that spot. 

Okay, so the blind spot isn't much of an evolutionary disadvantage. How
often
does it come into play, really (he asks, rhetorically)? I read, though,
that
baseball players have a problem with it. Certain pitches will bring the
ball
into the blind spot. At that point, based on the "launch window" for
intercepting the ball with the bat, the blind spot can be nasty. It
doesn't
take too much too much effort to devise an alien where evolution
required a
very small (no? is that possible, biologically?) blind spot.

Or... maybe they DO have a blind spot, perhaps a nasty one. One of the
interesting concepts in the film "Pitch Black" is the blind spot of the
alien
critters, though in this case it was based on extreme binocular "vision"
and
not from a retina. (I think they used sonar to see, as the planet was,
well,
pitch black most of the time.)

This is all neat stuff to think about. There should be an evolutionary
reason
for KV seeing into the IR and UV ranges, and for how far they see into
them. I
like the idea of them being less colour sensitive than humans, but more
sensitive to motion and contrast. More rods than humans but fewer cones.
I
like the PSB potential for hiding from a KV as long as you are VERY
still and
in cammo. Sort of would make sense if the KV came from such a nasty
environment that everthing seems predatory, ready to strike at you
quickly.
(Although in that case I'd suspect that being a critter that hid very
still
would be an evolutionary advantage...)

Allan Goodall		       awg@sympatico.ca
Goodall's Grotto:  http://www.vex.net/~agoodall

"Now, see, if you combine different colours of light,
 you get white! Try that with Play-Doh and you get
 brown! How come?" - Alan Moore & Kevin Nolan,