[FRIAM] Spandrel

[thompnickson2 at gmail.com]

Hi Dave,  

Ok, since you are also a metaphor enthusiast, let me explain a spandrel in
terms of its root metaphor.  A spandrel, originally, is a decoration on the
curved triangular spaces formed by the intersection of two perpendicularly
intersecting archways.  The decorations are so suited to their settings that
one might imagine that the hallways were designed to accommodate them, but,
of course, it is they that are suited to fit the spaces affording by the
intersecting hallways.  The same confusion exists with the human nose.  The
nose is presumably what was left over when the brain expanded, and the gut
and the jaw shrank.  It has been elaborated since to accommodate its new
position, but the nose it self is the result of other adaptations, not of an
adaptation FOR a nose.  The most graphic example, of course, of a spandrel
is the erectal and colored pseudopenis (hypertrophied clitoris) born by the
female stripped Hyena.  It is not an adaptation itself, but a consequence of
powerful selection between female genealogies for feeding competition at the
kill, which has select for high levels of testosterone in females.  (The
females are heavier than the males, and, in general more nasty in every way
-- definitely examples of testosterone poisoning.)  The coloration of the
pseudopenis is the spandrel-part, because selection has subsequently led to
its "decoration".  Put another way, a spandrel is a phenomenon which is an
elaboration of an epiphenomenon.

Does that help at all?

Nick     

Nick Thompson
ThompNickSon2 at gmail.com
https://wordpress.clarku.edu/nthompson/


-----Original Message-----
From: Friam <friam-bounces at redfish.com> On Behalf Of Prof David West
Sent: Saturday, March 13, 2021 2:43 PM
To: friam at redfish.com
Subject: [FRIAM] Spandrel

A while back there was a lot of discussion of spandrels that I failed to
grasp. 

Is a spandrel a stable morphological trait that results from random chance
rather than natural selection?

Or am I still ignorant.

Davew

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