tag:blogger.com,1999:blog-37148773.post8630368496658740135..comments2024-03-27T14:50:47.345-04:00Comments on <center>Sandwalk</center>: Nicholas Wade Writes about Genomes and EvolutionLarry Moranhttp://www.blogger.com/profile/05756598746605455848noreply@blogger.comBlogger16125tag:blogger.com,1999:blog-37148773.post-26220517348791031452010-06-20T00:35:47.883-04:002010-06-20T00:35:47.883-04:00What Jud said..that also was my rationale for why ...What Jud said..that also was my rationale for why I thought there was an evolutionary ladder.<br />Thanks for the clarification, Jud, and also Psi.Kathttps://www.blogger.com/profile/12542426899890871618noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-79289539333850963602010-06-19T08:45:55.363-04:002010-06-19T08:45:55.363-04:00People who are in an ego-boosting competition with...People who are in an ego-boosting competition with the other organisms to have more genes would do well to remember that onions have about 50,000, if I recall correctly.Monadohttp://sciencenotes.wordpress.comnoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-30217051508496837492010-06-15T09:36:38.699-04:002010-06-15T09:36:38.699-04:00Oh knows! The christian isn't going to like be...Oh knows! The christian isn't going to like being just another form of life, they might even prefer to be lower on the ladder than being totally without.<br /><br />Christians should be happy that they aren't higher than (non-talking) snakes. However, christians should always bray for talking snakes and thank them for making the christian experience possible.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-71805987436287258612010-06-15T07:14:17.361-04:002010-06-15T07:14:17.361-04:00On Katie's question, from an absolute amateur ...On Katie's question, from an absolute amateur (I'm not a geneticist/biologist):<br /><br />Stephen Jay Gould wrote about conceiving evolution as a bush against a wall. <br /><br />Evolution begins at a quite simple level - self-replicating molecules, let's say. Now evolution is undirected, so it branches out like a bush from ancestors to progeny. But if the self-replicating molecules get any simpler, they're no longer self-replicating and no longer capable of evolving. That's the "wall." There is no barrier in the other direction (greater complexity).<br /><br />So multicellular species evolve with multicellular versions of vital systems like respiration, digestion, excretion, reproduction, etc. Meanwhile quite simple virii and unicellular life forms evolve to out-compete or coopt the original self-replicating molecules, and they evolve into lots more species of virii and unicellular life forms.<br /><br />Some folks look at this situation and see an evolutionary direction from lesser to greater complexity. But that's an illusion caused by the fact that undirected evolution proceeds in all directions, except where evolution toward greater simplicity would produce non-life.Judnoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-17633535542122575702010-06-15T01:02:23.438-04:002010-06-15T01:02:23.438-04:00@ Psi Wavefunction:
It may be a minority view, bu...@ Psi Wavefunction:<br /><br />It may be a minority view, but it neatly explains a lot of observations and will eventually have to adopted widely. <br /><br />It has some very deep theological implications though (it pretty much completely destroys even Francis Collins' and Ken Miller's claims about evolution and God, or at least it makes them even more obviously equivalent to Old Earth Creationism), so it will be a tough pill to swallow for many. I am actually surprised that no creationists have attacked it yet, but that's probably because they can't understand the science behind it.Georgi Marinovhttps://www.blogger.com/profile/12226357993389417752noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-46529733756551944132010-06-15T00:46:47.317-04:002010-06-15T00:46:47.317-04:00Geometric Optics and Georgi:
Yes, I do completely ...Geometric Optics and Georgi:<br />Yes, I do completely agree that in some [most?] ways we are 'less' evolved - retardedly long generation spans and small eff pop size (Ne) make us quite awkward. In fact, I like to argue that multicellularity as a whole is rather stupid in many ways, and is an example of [constructive] neutral evolution gone mad. Rapid morphological diversification is not necessarily a sign of success, and makes sense for multicel things:<br /><br />multicellularity leads to larger, more resource-demanding organisms with longer generation spans, which crudely-speaking leads to lower Ne, which leads to more rampant drift and fixation of slightly deleterious alleles; since there are more ways to have complexity bloated than reduced while remaining functional, this tends to lead to more cumbersome lifeforms that can persist due to low Ne and inhabiting a different niche from the more streamlined competition, which enables more drift and such... and we end up with utterly stupidly 'designs' like large metazoa. The positive feedback tendencies of the system would explain how [morphological] diversification and complexity 'bloating' can happen so rapidly in a short period of time.<br /><br />On a smaller scale, a similar thing must've happened around the time of eukaryogenesis. <br /><br />Of course, the above view is a bit of a minority one, so I wouldn't really push it onto the public just yet. Many evolutionary biologists still dismiss non-adaptationist views. Step 1 is dispelling the <i>scala naturae</i> myth, and it's still not finished...<br /><br />For anyone interested, I do have a few posts pertaining to neutral evolution over on my blog... [/shameless advertising]Psi Wavefunctionhttps://www.blogger.com/profile/10829712736757471647noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-12919207748498815062010-06-14T17:09:25.072-04:002010-06-14T17:09:25.072-04:00Assigning a value hierarchy to species in terms of...Assigning a value hierarchy to species in terms of evolution sounds a little like the sort religious thinking that spawned the great chain of being.Unknownhttps://www.blogger.com/profile/14670539819476971641noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-80040389940970855442010-06-14T07:18:02.671-04:002010-06-14T07:18:02.671-04:00Psi, I'd like to suggest that we are are actua...<i>Psi, I'd like to suggest that we are are actually less evolved than "lower life forms". We're all the same number of years old, but they have both larger population bases and gone through a great many more generations in that time than our esteemed K-selected selves.</i><br /><br />And we also have a lot more non-adaptive and maladaptive traits due to the effects of small population size. Which is also completely left out of the discussion 99% of the time, while it is absolutely essential for understanding the subjectGeorgi Marinovhttps://www.blogger.com/profile/12226357993389417752noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-68503052887025133912010-06-14T07:09:38.925-04:002010-06-14T07:09:38.925-04:00Another outrageous line:
"chip sequencing, w...Another outrageous line:<br /><br />"chip sequencing, which gives researchers access to the mysterious and essential chromatin, the complex protein machinery that both packages the DNA of the genome and controls access to it"<br /><br />If you don't know what ChIP stands for, you have no business writing about genomes...Georgi Marinovhttps://www.blogger.com/profile/12226357993389417752noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-27135330717780605902010-06-14T02:51:57.310-04:002010-06-14T02:51:57.310-04:00Psi, I'd like to suggest that we are are actua...Psi, I'd like to suggest that we are are actually <em>less</em> evolved than "lower life forms". We're all the same number of years old, but they have both larger population bases and gone through a great many more generations in that time than our esteemed <a href="http://en.wikipedia.org/wiki/K-selection" rel="nofollow">K-selected</a> selves.<br /><br />Evolution = random mutation + natural selection.<br /><br />Natural selection is <a href="http://www.darwinawards.com" rel="nofollow">perpetually ongoing</a>, but (persistent Germ-line) mutation happens once per generation.Geometric Opticsnoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-80493654778221931312010-06-14T02:50:57.947-04:002010-06-14T02:50:57.947-04:00Psi, I'd like to suggest that we are are actua...Psi, I'd like to suggest that we are are actually <em>less</em> evolved than "lower life forms". We're all the same number of years old, but they have both larger population bases and gone through a great many more generations in that time than our esteemed <a href="http://en.wikipedia.org/wiki/K-selection" rel="nofollow">K-selected</a> selves.<br /><br />Evolution = random mutation + natural selection.<br /><br />Natural selection is <a href="http://www.darwinawards.com" rel="nofollow">perpetually ongoing</a>, but (persistent Germ-line) mutation happens once per generation.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-74966162791337602342010-06-13T22:14:11.224-04:002010-06-13T22:14:11.224-04:00@Katie (hope you don't mind a response from a ...@Katie (hope you don't mind a response from a random blogger...)<br /><br />Simple: All extant lifeforms have been evolving the same amount, the same length of time. No life form is 'more' or 'less' evolved than any other. When we say a certain organism is more or less 'derived' or 'modified', it's really a lousy shorthand for saying that a specific, very narrow, feature we are looking at has changed more in one organism than another with respect to the -inferred- ancestral state (which we don't actually ever know, as we were never there). <br /><br />In fact, if you ever see anyone, including professional biologists, utter things like "species x is more derived/evolved than species y", feel free to give them a dirty look. They should, in theory, know better.<br /><br />As for extinct species, an argument could be made that they evolved a lesser duration of time than modern ones; though it is a very weak and pointless argument considering the directionless nature of evolution itself.<br /><br />We're all ~3.5 billion years old.<br /><br />Disclaimer: Being a protistologist, I do have a strong personal interest against the evolutionary ladder. I'm sick of people referring to my organisms as 'primitive' or 'lower'. From the perspective of cell biology, most protist cells are far more complex and sophisticated* than animal or plant cells could ever dream to be.<br /><br />With respect to biochemistry and genetic diversity, prokaryotes kick our sorry little asses all the way to outer space.<br /><br />*no real definition of complexity/sophistication exists either, FYI.Psi Wavefunctionhttps://www.blogger.com/profile/10829712736757471647noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-70163085146789399622010-06-13T21:51:22.482-04:002010-06-13T21:51:22.482-04:00I came across your blog (which I enjoyed, by the w...I came across your blog (which I enjoyed, by the way) for the first time today because it was linked to by PZ Meyers. I subscribe to the science blog feeds because I am about to begin transitioning to a bioinformatics major from computer science. <br />I've read enough on genetics and biology that I found the Times writer's shock at the small gene difference silly, but I didn't know to take issue with the "evolutionary ladder" comment. Perhaps you, Jonathan, or PZ could do a small evolutionary primer to further elucidate the errors in the "evolutionary laddder" comment for those with minimal evolution knowledge?Kathttps://www.blogger.com/profile/12542426899890871618noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-83770038577026492992010-06-13T20:43:14.855-04:002010-06-13T20:43:14.855-04:00Funny enough, the ciliate use of non-coding RNA an...Funny enough, the ciliate use of non-coding RNA and other epigenetic gymnastics makes that of animals and plants pale in comparison... which makes sense, as I'm convinced ciliates ARE the higher eukaryotes =PPsi Wavefunctionhttps://www.blogger.com/profile/10829712736757471647noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-18056575033451612602010-06-13T13:35:46.569-04:002010-06-13T13:35:46.569-04:00This is really fascinating context for the issue. ...This is really fascinating context for the issue. <br /><br />It amazes me how much of a gap there is between expert knowledge and popular impression of that knowledge. This really speaks to the importance of *good* science writing and the necessity of evaluating science writing and appreciating the good writers.Todd I. Starkhttps://www.blogger.com/profile/02231844857877577527noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-43914526090672682872010-06-13T13:02:38.580-04:002010-06-13T13:02:38.580-04:00Nice background - wish I had remembered who had wr...Nice background - wish I had remembered who had written the discussion of genes in the human genome from years before I wanted to refer to ... now I know it was you. Gonna add it to my post ...Jonathan Eisenhttps://www.blogger.com/profile/07953790938128734305noreply@blogger.com