Let me attempt to echo what i think I understand from your example and previous discussions where I lurked:
A mutation occurs in an organism resulting in an morphological change — i.e. a nose, modified jaw, and modified brain case. I assume, *first potential error*, that this is a 'singular' change (e.g. a "face"), not three separate mutations and three different morphological changes to three different parts of the organism? [If there are three separate events, then how are they "coordinated?"] One aspect of the original change, the nose, continues to change — is "decorated." Second assumption (*error*): the same forces, mutation/selection, that cued the 'face' are prompting promulgation of new nose morphologies, the 'decorations'; which are selected among. *Core misunderstanding*: it seems as if this demands some kind of "focused," on the nose, "micro-evolution." I do not see how such a weird phenomenon is _not_ required; but cannot fathom from whence, and how, it came. If mutation/selection occurs only at the 'whole', i.e. the face, then I do not see why any aspect of that face is "isolated" such that localized change is deemed somehow independent of global change and therefore merits the label: spandrel. Now that you see how deep I am in a well of misunderstanding, is rescue possible or is it time to pour in the cement and cap the well? davew On Sat, Mar 13, 2021, at 9:21 PM, [email protected] wrote: > Well, “elaboration of an epiphenomenon” was not the core of the mechanism I > described. It was a fancy little idea I added at the end. So what about the > mechanism that I described was difficulty to undertad. > > n > > Nick Thompson > [email protected] > https://wordpress.clarku.edu/nthompson/ > > *From:* Friam <[email protected]> *On Behalf Of *Prof David West > *Sent:* Saturday, March 13, 2021 8:41 PM > *To:* [email protected] > *Subject:* Re: [FRIAM] Spandrel > > Nick, > > first apologies for arrogance in first reply. I should have said that I find > the definition derived from Bonner to be more understandable — to me — and, I > think, it offers an actual mechanism / rationale that is absent, again to me, > than "elaboration of epiphenomenon." I am enjoying the essay and i see an > interesting connection with Wegner's *Arrival of the Fittest* book. That > means Jenny Q will have to read it because and I are working on a paper in > that area. > > davew > > > On Sat, Mar 13, 2021, at 5:37 PM, [email protected] wrote: > > Bonner's a great guy, but I think he's wrong on that, or you're wrong > > in interpreting him. The whole thrust of Lewontin and Gould's work is > > that there are developmental constraints in evolution. Even according > > to orthodox Darwinian theory, mutation is random, but only with respect > > to the opportunities a mutation affords. Nothing says that a mutation > > can' be predictable, yet random in this sense. Any "random" assertion > > requires a point of view from which the stated variable is random. Any > > geneticist can tell you which mutations are more likely than others. > > > > 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 6:04 PM > > To: [email protected] > > Subject: Re: [FRIAM] Spandrel > > > > 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/ > > > > > > - .... . -..-. . -. -.. -..-. .. ... -..-. .... . .-. . > > 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/ >
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