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From: wmartin@brl-tgr.ARPA (Will Martin )
Newsgroups: net.bio,net.origins,net.rec.birds
Subject: Evolution of vision-based instincts
Message-ID: <1654@brl-tgr.ARPA>
Date: Mon, 23-Sep-85 11:24:15 EDT
Article-I.D.: brl-tgr.1654
Posted: Mon Sep 23 11:24:15 1985
Date-Received: Wed, 25-Sep-85 10:55:39 EDT
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Organization: USAMC ALMSA, St. Louis, MO
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Xref: linus net.bio:138 net.origins:2407 net.rec.birds:214

I ran across the following passage in a rather interesting coffee-table
(big-format, lotsa pictures) book called HOW ANIMALS SEE, by Sandra
Sinclair (Facts on File, 1985):

Celestial Navigation

Observation and experimentation in planetariums have shown that birds
navigate by the stars and know their positions. Dr. Sauer of Freiburg
University raised night-migrating warblers in confinement, then took them 
to a planetarium with projected replicas of the major stars. The baby
birds adjusted their position to the direction in which the parents were
already flying. When he changed the positions of the stars, the birds
readjusted themselves. Other experiments with various species of 
night-flying birds heve replicated the reults of these experiments,
some of which were conducted in exterior cages under the stars.

It requires an extremely large eye to detect small points of light
at great distances, and the eye of the bird is certainly big enough
to perceive starlight. What is of greater interest in the
experiments of Dr. Sauer is that knowledge of the stars' positions
appears to be innate, like the innate attraction of young gulls to
yellow and red spots.              (page 97)

***End of quote***

Now, note especially the last sentence above. What came to mind as I
read that was this question: "How could such an innate ability, or
'instinct', evolve?" Especially since the position of the stars
CHANGES over the millenia -- far too slowly to be visible, but 
the pattern(s) of stars in the sky (which presumably is what the
birds are comparing with 'internal templates' to navigate) is not
the same 100,000 years, or a million years, ago.

If "Lamarckism" or the inheritance of acquired characteristics, is
a false concept (as we have been taught), how could the learning
of such CHANGING patterns have ever become an "innate" instinct?
You can postulate the usual random evolutionary methods making
some birds survive because they had a randomly-generated internal
star map installed by mutation that happened to match more accurately
the real night sky, and the others, who got mutated to have wrong
internal star maps, flew out to sea and died, but I would think that
such a mechanism would result in most of the species dying off
fairly quickly.

Also, the newer concepts of "punctuationalism", or brief spurts of
frantic evolutionary change, doesn't work well here -- suppose
that change-spurt happened 200,000 years ago. The birds would then
have 200,000-year-old star maps genetically encoded, and would
either have to have gradual evolution changing those maps over
the intervening years, or have all navigated wrong beginning whenever the
star positions have changed enough to invalidate their genetic 
encoded charts. (And how would such gradualism have occurred over the
intervening years without Lamarck-like processes driving it?)

I find this a rather large puzzle. Please comment!
Will Martin

UUCP/USENET: seismo!brl-bmd!wmartin   or   ARPA/MILNET: wmartin@almsa-1.ARPA