Nick, thank you. I get the metaphor but I think my “definition” is more correct than ‘elaboration of epiphenom’. I get that notion from an essay I am reading on randomness in evolution by John Tyler Bonner
Davew On Sat, Mar 13, 2021, at 2:08 PM, [email protected] wrote: > 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/ > - .... . -..-. . -. -.. -..-. .. ... -..-. .... . .-. . 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/
