tag:blogger.com,1999:blog-1812431336777691886.post8811839446223139748..comments2024-02-29T03:57:00.088-05:00Comments on The Mermaid's Tale: On the mythology of natural selection: Part III. Organismal selectionAnne Buchananhttp://www.blogger.com/profile/09212151396672651221noreply@blogger.comBlogger4125tag:blogger.com,1999:blog-1812431336777691886.post-69007261480675286332014-07-17T22:42:03.855-04:002014-07-17T22:42:03.855-04:00Reply to Anonymous:
Even Darwin recognized vestigi...Reply to Anonymous:<br />Even Darwin recognized vestigial traits. Many traits, as many if not perhaps most individual nucleotides in genomes, have little if any function. Some may at one time have had a function and when environmental or other genomic etc circumstances changed, those traits became irrelevant to selection. Or, they could be the functionless by-product of some, say, developmental process that also yields an important structure or function.<br /><br />There's no one rule--perhaps that IS the rule! <br /><br />The appendix is, however, thought to have some immune and/or other functions (if you Google it you can find out); it's I think out of date to consider it vestigial. Our pheromone sensing vomeronasal system may be closer to that--perhaps.<br /><br />As to 'junk' DNA, that idea is past its sell-by date. Much DNA has little or no known function, but there can be many subtle DNA functions that we simply don't know about. The Encode project is identifying transcribed (into RNA) bits of DNA whose actual function (if any) is currently unknown.<br /><br />If you go to Evolutionary Anthropology and look for my article "Do we understand the genetic basis of evolution?" vol 23 88-92, this year, and my article in the prior issue on "What works works" I discuss some of these things.<br /><br />Functions can come and go, be minor but not zero in strength, or be very indirect. The one thing I believe we can be sure of is that we can't be sure, that 'natural selection' is not the only criterion, especially as regards conservation, and that chance is important--topics coming up in this blog-post series.Ken Weisshttps://www.blogger.com/profile/02049713123559138421noreply@blogger.comtag:blogger.com,1999:blog-1812431336777691886.post-90220820320737051052014-07-17T22:23:53.387-04:002014-07-17T22:23:53.387-04:00Are there traits that neither hinder nor help repr...Are there traits that neither hinder nor help reproductive success (greying of hair) or were all traits originally adaptive but remain as "harmless" vestiges like the appendix? Is the "vestigialization" of traits adaptive or is it like "junk" DNA? What is junk DNA for that matter? It was presumably adaptive at one point or was it just a harmless and not helpful accident?<br /><br />I'm sorry, too many questions; I'll just patiently read-on.<br /><br />Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-1812431336777691886.post-85170557804258604872014-07-17T21:28:51.076-04:002014-07-17T21:28:51.076-04:00Reply to Manoj,
Nobody can explain this at present...Reply to Manoj,<br />Nobody can explain this at present, because nobody knows what consciousness 'is', or what species have it. Going back to Wm James in the 19th century and up through Francis Crick (yes, the DNA guy) and colleagues, all we can do is study the 'neural correlates of consciousness'.<br /><br />But selection by favoring whatever trait works can lead to the evolution of consciousness if the latter has had a history of conferring higher fitness on its bearers. It would not be inevitable, just if the right traits, from rudiment to what exists now, happen to have been present. <br /><br />So I think selection per se is not the issue, indeed, the captivating and mesmerizing appeal of natural selection is just that: it can bring about whatever is presented as alternatives.<br /><br />At the same time, so might the various other forms of differential proliferation that we try to discuss in this series.<br /><br />My own view is that the existence of consciousness, is itself evidence of evolution having favored judgment vs hard-wiring, the ability (however it works) to assess sensory input, think about it, and make what appear to be the best decisions on how to respond. That is a form of flexibility that is the very opposite of the genomic hard-wiring that so many, in our day of hyper genomic determinism, seem to embrace.<br /><br />One can construct scenarios by which organismal selection, rather than natural selection, led to consciousness in what eventually became our species (or those that have it). If we're the only ones, it may have to do with language or our form of abstract thinking, and those with similar bents aggregated (organismal selection). <br /><br />I like the thought! But at this stage it is just the kind of Just-So story we should all try to avoid! Ken Weisshttps://www.blogger.com/profile/02049713123559138421noreply@blogger.comtag:blogger.com,1999:blog-1812431336777691886.post-36340879960005968822014-07-17T21:11:40.645-04:002014-07-17T21:11:40.645-04:00great series !!
I am wondering how natural select...great series !!<br /><br />I am wondering how natural selection explains the phenomenon of consciousness.Manoj Samantahttps://www.blogger.com/profile/04264467983614167240noreply@blogger.com