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 [email protected] https://wordpress.clarku.edu/nthompson/ -----Original Message----- From: Friam <[email protected]> On Behalf Of Prof David West Sent: Saturday, March 13, 2021 2:43 PM To: [email protected] 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 - .... . -..-. . -. -.. -..-. .. ... -..-. .... . .-. . FRIAM Applied Complexity Group listserv Zoom Fridays 9:30a-12p Mtn GMT-6 bit.ly/virtualfriam un/subscribe http://redfish.com/mailman/listinfo/friam_redfish.com FRIAM-COMIC http://friam-comic.blogspot.com/ archives: http://friam.471366.n2.nabble.com/ - .... . -..-. . -. -.. -..-. .. ... -..-. .... . .-. . FRIAM Applied Complexity Group listserv Zoom Fridays 9:30a-12p Mtn GMT-6 bit.ly/virtualfriam un/subscribe http://redfish.com/mailman/listinfo/friam_redfish.com FRIAM-COMIC http://friam-comic.blogspot.com/ archives: http://friam.471366.n2.nabble.com/
