tag:blogger.com,1999:blog-37148773.post2205336848021818591..comments2024-03-19T00:24:23.577-04:00Comments on <center>Sandwalk</center>: The Many Definitions of EvolutionLarry Moranhttp://www.blogger.com/profile/05756598746605455848noreply@blogger.comBlogger52125tag:blogger.com,1999:blog-37148773.post-64153121574299125752013-10-07T12:02:07.212-04:002013-10-07T12:02:07.212-04:00No, but it really pisses me off when people make g...No, but it really pisses me off when people make grandiose claims about evolution based entirely on what happens in some subset of species that they happen to know about. It's even worse when that subset happens to be humans and their close cousins. Larry Moranhttps://www.blogger.com/profile/05756598746605455848noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-29961544079552064782013-10-07T11:00:17.406-04:002013-10-07T11:00:17.406-04:00Is that the only thing he got wrong, Larry? ;)Is that the only thing he got wrong, Larry? ;)Faizal Alihttps://www.blogger.com/profile/00937075798809265805noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-74443644177915578482013-10-07T10:53:56.340-04:002013-10-07T10:53:56.340-04:00You do realize, don't you, that multicellular ...You do realize, don't you, that multicellular animals represent only a tiny percentage of all life on Earth? Larry Moranhttps://www.blogger.com/profile/05756598746605455848noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-27520734324032094112013-10-07T05:29:56.711-04:002013-10-07T05:29:56.711-04:00On the basis of some paleontological readings, the...On the basis of some paleontological readings, the main macro evolutionary changes take place only in the period of ecological crisis. Since the organic progress is a complication of the internal organization of live systems, it may lead to a logical inference that the indispensable condition complexity of the internal organization is an alteration of homeostasis. But, a stable disturbance of homeostasis is called “disease”. Consequently, disease is prerequisite for the organic progress. <br /> Disease is a breakage of self-controlling and regulation, including genetic processes. How reads, interprets a damaged cell the hereditary information? In the case of a non-classical transfer of genetic information, the above-stated question deserves a specific treatment. There is reason to assume, that the “erroneously” or “alternatively” realized genetic information in the damaged cells may become one of the major factor-provider of the evolutionary material.<br /> The micro-changes of the genetic activity in the damaged cells are not ignored by the “magnifying lens of natural selection”. Better adapted organisms survive and multiply successfully.<br /> The complication of the inner structure - an organic progress is an answerable reaction for the influence of pathological factors, which takes place on the historical periods (for example while global ecological catastrophes). The aim of it is a restoration of damaged homeostasis – recovering of filum, by creating the new evolution forms. Typical pathologic processes are the tools for the creation of new forms during the process of organic development (progress).<br /> The excess of pathologic substrate detected at the onset of an individual development, both at the tissue, cellular and molecular levels, confirms that disease played an important role in the evolutionary transformations. Complex genetic, metabolic, morphologic changes that take place in embryogenesis are the reflection, in a tiny model, of those pathologic processes, to which adult ancestor embryos had been exposed on the corresponding stages of phylogenetic development, while ontogenesis itself presents a short history of disease of filum. By those characteristic nuances of the pathologic changes which take place in the developing organs, we may surmise, which pathology might have been the cause of those changes in the process of the organic progress. Disease itself is a developing style of living matter. Pathology, as a process of struggle for survival, is the only way, an essential condition of the progressive evolution. The progressive evolutionary objects were diseased organisms, “hopeful patients”. Pathology is a lack circle of evolution theory, some kind of Terra incognita, where there is hidden the answers of many actual questions of Evolution theory.Anonymoushttps://www.blogger.com/profile/03842208308607819119noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-4743692753136531672013-10-05T15:10:47.762-04:002013-10-05T15:10:47.762-04:00I was noting that the question of what accounts fo...I was noting that the question of what accounts for the fixation of type O alleles in South America can be addressed without any need for a precise definition of evolution. That fact that people like Dawkins or Maynard Smith don't (or in JMS's case didn't) consider genetic drift to be an important part of evolution is irrelevant.<br /><br />We can ask, and maybe even answer, the Type O question without the definition of evolution. The point is that many, and I would even say most, questions in evolutionary biology do not require a precise definition of "evolution".<br /><br />I suspect the same holds for "biochemistry".Joe Felsensteinhttps://www.blogger.com/profile/06359126552631140000noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-22714964831427346592013-10-04T10:15:55.370-04:002013-10-04T10:15:55.370-04:00Joe asks,
I asked: when we try to figure out whet...Joe asks,<br /><br /><i>I asked: when we try to figure out whether the fixation of type O alleles in native South American populations is due to selection or to drift, why do we need a formal definition of evolution?</i><br /><br />In order to answer your question all you need to do is establish proper definitions of selection and drift.<br /><br />On the other hand, if you ask whether the fixation of O alleles is an example of EVOLUTION you need to agree on a definition of evolution. <br /><br /><i>PS John Maynard Smith was quite keenly aware of genetic drift and neutral mutation, and did not at all advocate ignoring them.</i><br /><br />I do not claim the he was unaware of drift. I claim that he considered it to be trivial and not really important in evolution. <br /><br />John Maynard Smith managed to write an entire book (with Szathmary) on "The Major Transitions in Evolution" (1995). He never mentioned drift, even once, as far as I can tell. Could you do that, Joe? Could you write an entire book without mentioning the possibility that something might have arisen by drift?<br /><br />Furthermore, Maynard Smtih explains his perspective in the opening chapter where he says, "The transitions must be explained in terms of immediate selective advantage to individual replicators: we are committed to the gene-centered approach outlined by Williams (1966), and made more explicit by Dawkins (1976)."<br /><br />Michael Lynch could never write that and neither could I. How about you Joe (or anyone else reading this)? Could you commit to the idea that major transitions "MUST be explained in terms of immediate selective advantage"? Larry Moranhttps://www.blogger.com/profile/05756598746605455848noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-38854196820700459262013-10-04T09:01:01.408-04:002013-10-04T09:01:01.408-04:00The issue of whether or not genetic drift "co...The issue of whether or not genetic drift "constitutes evolution" is irrelevant to my point.<br /><br />I asked: when we try to figure out whether the fixation of type O alleles in native South American populations is due to selection or to drift, why do we need a formal definition of evolution?<br /><br />The fact that many people do not understand genetic drift, or that Richard Dawkins doesn't consider it to be evolution, does not solve the South American type O problem.<br /><br />I am still waiting to hear why making a definition of evolution has any bearing on what happened to the type O alleles. And that question is just a place-holder for many others that also do not depend on what gets defined as evolution.<br /><br />PS John Maynard Smith was quite keenly aware of genetic drift and neutral mutation, and did not at all advocate ignoring them.<br /><br />Joe Felsensteinhttps://www.blogger.com/profile/06359126552631140000noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-18266450756133387492013-10-03T16:43:05.625-04:002013-10-03T16:43:05.625-04:00Picky? No, just noticing that your claim was wrong...Picky? No, just noticing that your claim was wrong. Dawkins wasn't agreeing with Maynard Smith, if that's even what Maynard Smith meant. He was just making a claim that neutral evolution doesn't affect phenotype. We could argue about whether that's true (I agree that it almost certainly isn't), but it hardly has anything to do with Dawkins' definition of evolution. I truly do not understand why you're so exercised about this.John Harshmanhttps://www.blogger.com/profile/06705501480675917237noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-70623571408314343372013-10-03T16:23:39.899-04:002013-10-03T16:23:39.899-04:00Oops. I forgot to point out that it was Maynard Sm...Oops. I forgot to point out that it was Maynard Smith who said "In this sense, the substitution of a neutral allele would not constitute evolution ...." and Dawkins was just agreeing with him.Larry Moranhttps://www.blogger.com/profile/05756598746605455848noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-30113019874959826232013-10-03T16:13:21.746-04:002013-10-03T16:13:21.746-04:00John, you are really being picky. Why?
It should ...John, you are really being picky. Why?<br /><br />It should be clear from my post that Richard Dawkins goes out of his way to avoid using the term "genetic drift." Instead, he refers to "Neutral Theory." What he's talking about is the fixation of neutral alleles and the fact that he doesn't specifically mention genetic drift should not lull you into a false sense of "gotchaism."<br /><br />When Dawkins says, "In this sense, the substitution of a neutral allele would not constitute evolution ...." do you really think I'm doing him a disservice by saying that Dawkins, "has argued in the past that changes in allele frequencies due to random genetic drift don't really count as evolution"? <br /><br />Do you really want to insist that the only correct way to describe Dawkins' view is to say something like, "In the past Dawkins has said that the fixation of neutral alleles (by an unspecified mechanism) doesn't really count as evolution"?Larry Moranhttps://www.blogger.com/profile/05756598746605455848noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-70455682090930728252013-10-03T15:02:45.810-04:002013-10-03T15:02:45.810-04:00I didn't find anything in your quotations from...I didn't find anything in your quotations from Dawkins to suggest that drift doesn't count as evolution. What was I missing?John Harshmanhttps://www.blogger.com/profile/06705501480675917237noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-64758627344238960402013-10-03T14:57:08.233-04:002013-10-03T14:57:08.233-04:00All of the higher levels of evolution encompass th...<i>All of the higher levels of evolution encompass this minimal concept or they wouldn't be examples of evolution. The only exception is extinction, which is a special case.</i><br /><br />That isn't true, and even your second sentence acknowledges it. Higher levels of evolution do not involve change in allele frequencies in populations. They involve differential speciation and extinction with no particular expectation of change within populations. If you want to say those aren't evolution, that's fine. But don't simultaneously claim they are evolution and that your definition encompasses them.John Harshmanhttps://www.blogger.com/profile/06705501480675917237noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-7701741342562622462013-10-03T14:49:34.419-04:002013-10-03T14:49:34.419-04:00@Allan Miller,
To see Dawkin's view, check ou...@Allan Miller,<br /><br />To see Dawkin's view, check out: <a href="http://sandwalk.blogspot.ca/2009/10/richard-dawkins-view-of-random-genetic.html" rel="nofollow">Richard Dawkins' View of Random Genetic Drift</a><br /><br />Ernst Mayr's take is summarized in: <a href="http://sandwalk.blogspot.ca/2007/07/what-is-darwinism.html" rel="nofollow">What Is Darwinism?</a>Larry Moranhttps://www.blogger.com/profile/05756598746605455848noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-27215403467755388132013-10-03T10:02:16.421-04:002013-10-03T10:02:16.421-04:00Larry I guess you've never discussed that topi...Larry <i>I guess you've never discussed that topic with Richard Dawkins! He has argued in the past that changes in allele frequencies due to random genetic drift don't really count as evolution. So has Ernst Mayr. </i><br /><br />Do you have a reference?AllanMillerhttps://www.blogger.com/profile/05955231828424156641noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-16936350890250277222013-10-03T09:49:41.931-04:002013-10-03T09:49:41.931-04:00Gnnnnhhh! *arbitrary!Gnnnnhhh! <i>*arbitrary!</i>AllanMillerhttps://www.blogger.com/profile/05955231828424156641noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-24381013448460278152013-10-03T09:48:55.887-04:002013-10-03T09:48:55.887-04:00twt - At a minimum, it could be any bit or bit ser...twt - At a minimum, it could be any bit or bit series in the genome of an individual that differs from the same position in the parent(s). Too small to be worth accounting for, but following fixation of one such, all descendants would see the 'moment the genome changed' as that minor, inconsequential blip. Promoting the generality of such blips as 'minimal evolution' might not be to everyone's taste, perhaps. But the insertion of 'over many generations' seems arvbitrary.AllanMillerhttps://www.blogger.com/profile/05955231828424156641noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-41616941878855619352013-10-03T09:42:44.722-04:002013-10-03T09:42:44.722-04:00Joe asks,
Not at all. In order to discuss whether...Joe asks,<br /><br /><i>Not at all. In order to discuss whether type O blood group has reached fixation in natirve South American populations by genetic drift or by natural selection, why do we need to first agree on What Is Evolution ? We don't need to, as far as I can see,</i><br /><br />I guess you've never discussed that topic with Richard Dawkins! He has argued in the past that changes in allele frequencies due to random genetic drift don't really count as evolution. So has Ernst Mayr. <br /><br />However, in most cases the problem isn't that people have considered drift and rejected it. It's that they don't even know about it so they assume that the only kind of change allowed is that due to natural selection. If that's the definition they start with then you're going to have a lot of trouble using random genetic drift as an explanation. <br /><br />You're probably also going to encounter resistance if you allude to the fact that deleterious mutations can be fixed in a population or that beneficial alleles might not fix. <br /><br />It's much better if everyone is on the same page at the beginning of the discussion. <br />Larry Moranhttps://www.blogger.com/profile/05756598746605455848noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-67824711262224381552013-10-03T09:32:37.558-04:002013-10-03T09:32:37.558-04:00John Harshman says,
But it's still not such ...John Harshman says,<br /><br /><i> But it's still not such a big deal; just definitions.</i><br /><br />Actually, I think that defining your terms IS a big deal. We'll have to agree to disagree on this one. <br /><br /><i>While we're on the subject of definitions, I don't know what you mean by "minimal". I would have taken it to mean the simplest definition that covers everything. But you favor a definition that you agree doesn't cover everything. What makes that minimal instead of something with even less coverage? What, in other words, does "minimal" mean to you?</i><br /><br />It means the minimum criteria that are required in order to declare that something counts as evolution. It covers the idea that it's populations that evolve and not individuals, that the characteristics that change are genetic (alleles), and that any change in the frequency of those characteristics in the gene pool counts as evolution. <br /><br />All of the higher levels of evolution encompass this minimal concept or they wouldn't be examples of evolution. The only exception is extinction, which is a special case. Larry Moranhttps://www.blogger.com/profile/05756598746605455848noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-12163877010039784712013-10-03T09:26:18.575-04:002013-10-03T09:26:18.575-04:00Larry, on the page you linked to that talks about ...Larry, on the page you linked to that talks about your favorite definition of evolution it says:<br /><br />"Evolution is a process that results in heritable changes in a population spread over many generations."<br /><br />How many generations? And what number would the rest of you put on "many"? And what is the minimum change that would satisfy the definition of "change"?The whole truthhttps://www.blogger.com/profile/07219999357041824471noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-14991692247723514222013-10-03T09:16:23.870-04:002013-10-03T09:16:23.870-04:00Alex SL says,
Still, I am a botanist. I am not su...Alex SL says,<br /><br /><i>Still, I am a botanist. I am not sure if any lay person would read a press release about genetic drift in some species of plants with the same curiosity as they would read a press release about the adaptation ...</i><br /><br />Really? Don't you think people might be curious about why different species of maple trees have leaves that are slightly different shapes and different colors? (e.g. red maple, silver maple, sugar maple)<br /><br />What about the different species of dandelion that they encounter? Might they wonder why the species differ only slightly in appearance so that it's difficult to tell them apart? How do you explain these things to the general public without mentioning the possibility that the differences might be due to chance rather than adaptation? Larry Moranhttps://www.blogger.com/profile/05756598746605455848noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-43349258145372971082013-10-03T09:03:33.681-04:002013-10-03T09:03:33.681-04:00Charles Darwin died on April 19, 1882. That's ...Charles Darwin died on April 19, 1882. That's more than 130 years ago. It's time to update the definition. Larry Moranhttps://www.blogger.com/profile/05756598746605455848noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-33226988334165494792013-10-03T09:03:12.760-04:002013-10-03T09:03:12.760-04:00Allan, what, at a minimum, would you count as modi...Allan, what, at a minimum, would you count as modification? Will you state some example please? The whole truthhttps://www.blogger.com/profile/07219999357041824471noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-85512380477050181472013-10-03T03:31:54.502-04:002013-10-03T03:31:54.502-04:00Robert, You say "I need evidence evolution is...Robert, You say "I need evidence evolution is a theory. I think its just a hypothesis supported, claimed, by non biological evidences."<br /><br />This is not the place for you to be, we can't teach understanding science here. To point out the obvious: We have been doing archaeology for a very long time. A lot of evidence of human activity has been found. Now tell me, are stone or flint tools, arrowheads or axes evidence of past humans existence and activity? If you want evidence, look for and study the evidence!<br /><br />Do you claim that fossilized bones are not evidence of past life? Are not insects captured in several million years old amber biological evidence?<br /><br />Please don't come back before you have learned anything.<br />Rolf Aalberghttps://www.blogger.com/profile/12878337054438652463noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-37313919037593547372013-10-02T21:44:02.600-04:002013-10-02T21:44:02.600-04:00"Descent with modification" is what Darw..."Descent with modification" is what Darwin called it in the Origin of Species.Allen MacNeillhttps://www.blogger.com/profile/13692148273564872787noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-83807450997091362952013-10-02T21:04:31.829-04:002013-10-02T21:04:31.829-04:00LAM,
You are correct, I had not given enough thou...LAM,<br /><br />You are correct, I had not given enough thought to the fact that people will find such stories interesting when they revolve around, well, people. Unless we are plant or animal breeders we observe the intraspecific variation of humans with much more interest than those in other species.<br /><br />Still, I am a botanist. I am not sure if any lay person would read a press release about genetic drift in some species of plants with the same curiosity as they would read a press release about the adaptation of that plant's flower to the needs of its pollinator, or about its adaptation to erratic rain fall regimes of the arid Australian interior.Alex SLhttps://www.blogger.com/profile/00801894164903608204noreply@blogger.com