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

On Fri, Jul 27, 2001 at 01:00:06AM -0400, Allan Goodall wrote:
> 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.

	As I understand it, the blind spot is present because the
visual nerves run "inside" the rods and cones. In octopus, on the
other hand, the nerves run "outside" the rods and cones, removing
the need for a blind spot.

	So, there's no _need_ for a blind spot.

-- 
						crawford@iac.net
"Half the harm that is done in this world is due to people who want
to feel important. They don't mean to do harm -- but the harm does not
interest them. Or they do not see it, or they justify it because
they are absorbed in the endless struggle to think well of themselves."
		-- T. S. Eliot