[cap-talk] Bee Eyes
mikesamuel at gmail.com
Mon Feb 2 16:38:58 EST 2009
2009/2/2 Steve Witham <sw at tiac.net>
> About charging into the valley of blindness, Jesus said, "If your right
> eye causes you to sin, pluck it out." But upon consideration he said,
> "First remove the plank from your own eye."
> Evolution seems to have crossed the gap between compound and
> single eyes in both directions. There's a fascinating variety of
> approaches including parabolic mirrors, corner reflectors,
> segment walls that retract under low light, and simple eyes wedged
> within compound eyes. The eye of some flying insects, including the
> bee, has a fovea--an area in the middle that gets better resolution
> using larger lenses.
> I'm pretty sure the gene-activation signal for "form an eye here" is
> the same for humans, bees and octopi, erm,
> While marveling at your own eye
> give a thought to the octopi
> whose optical nerves
> straighten out all the curves
> that cause blind spots for you and for I.
I thought mollusc and vertebrate eyes were a case of convergent evolution.
The different forms of eye in, for example, vertebrates and mollusks are
often cited as examples of parallel
At a cellular level, there appear to be two main "designs" of eyes, one
possessed by the protostomes
<http://en.wikipedia.org/wiki/Protostomes>(molluscs, annelid worms and
arthropods), the other by the deuterostomes
(chordates and echinoderms)
> MarkM says:
> >These have come up before on this list, and we've always concluded
> >(correctly IMO) that HCSs have no technical advantage over pure ocap
> >used with the Horton pattern. However, HCSs may provide the path through
> >valley of blindness that allows us to reach the higher hill.
> By technical advantage you mean in terms of the kinds of effects you
> could achieve if starting from scratch. But, migration also has its
> technical problems. We need a capital-O notation for human effort.
> cap-talk mailing list
> cap-talk at mail.eros-os.org
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