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Fosdick  Suspended Member (Idle past 5521 days) Posts: 1793 From: Upper Slobovia Joined: |
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Author | Topic: What exactly is natural selection and precisely where does it occur? | |||||||||||||||||||||||
Fosdick  Suspended Member (Idle past 5521 days) Posts: 1793 From: Upper Slobovia Joined: |
Modulous writes:
If I am a 'Neville Chamberlain' then who is a 'Hitler'? Wait, wait, let me guess. The big question is of individual and gene view selection. Some 'Neville Chamberlains' have proposed a compromise, that both views are valid depending on the situation. But more to the point:
I think the answer to where exactly does natural selection occur is at the gene level. Not the individual, the deme, the species or any other place in the heirarchy. There may be selection occurring, but it is not natural selection.
I mostly have to agree with your argument. ”HM
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crashfrog Member (Idle past 1488 days) Posts: 19762 From: Silver Spring, MD Joined: |
I've been held up for ridicule, called names like "schnook," You poor dear!
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Quetzal Member (Idle past 5893 days) Posts: 3228 Joined: |
Although I'm not entirely sure of the purpose it would serve, since Mod took the time to summarize his position, I suppose (in the absence of anyone else interested in so doing) I better summarize the opposing viewpoint. Some of the points below have been discussed in this thread, others may not have been directly addressed.
1. With the possible - albeit poorly understood and hence disputable - exception of the phenomenon known as segregation distortion (aka, meiotic drive), there is no known selection pressure that operates directly on a gene, suite of genes, or even genotype. Rather, selection affects the entire organism through either enhancing or restricting individual survival (the carrier of the gene), or over the longer term, the reproductive success or rate of the individual organism. Whereas a gene or polygene can be said to be "promoted" by selection if it increases in frequency in subsequent generations, it is actually the phenotypical expression of the gene that is affected. Since phenotype is ineluctably and directly tied to the interaction of the whole organism and its environment, attempting to understand this interaction in the context of genes (rather than individuals) tends to distort and/or add an unnecessary level of abstraction when discussing natural selection itself. 2. Genecentrism is in essence an evolutionary metaphor. As such, the viewpoint is not designed to - and thus cannot - make a distinction between selection itself and the evolutionary response to selection. Thus genecentrism is unable to address a whole gamut of interesting questions concerning the ecological effects on individuals, populations, etc, of environmental factors in a single (or a limited number of) generations. These questions are, in fact, dismissed as "uninteresting" in an evolutionary context. I submit, however, that for numerous disciplines such questions are not only not "uninteresting", but actually key to our understanding of nature and natural history. 3. Genecentrism dismisses most concepts of "fitness" as an organismal measure. At best, it allows only discussion of the relative fitness of particular alleles, and ignores the concept of absolute fitness. However, even here, there is really no effective way for genecentrists to measure such allelic fitness without implicitly or explicitly referring to the effect of those alleles on the individual which carries them - because, after all, it is the individual which passes those alleles on to subsequent generations. In other words, again we are adding an unnecessary level of abstraction to the discussion. Outside of the discipline of population genetics, this abstraction serves no function other than to obscure what occurs in nature. 4. There are a number of biological sciences where it simply makes no sense to insist on a genes-eye-view, primarily because these disciplines are more holistic in nature. The one that immediately springs to my mind is (of course) ecology. With the exception of those genetically-related elements such as certain aspects of population dynamics (for instance, inbreeding depression) and extinction or extinction threat (for instance, the phenomenon of extinction vortex), the insistence of the proponents of genecentrism that theirs is the only "accurate" viewpoint would perforce render much of ecology unworkable - or perhaps only "uninteresting" - because ecology is concerned primarily with macroscale (vice gene-level microscale) interactions. Since ecology is arguably the science most concerned with natural selection (writ large) in the wild, the fact that genecentrism is not particularly useful - and in fact may be unusable in many contexts - for that science should give the genecentrists pause. 5. And finally, on a very personal note, although I am aware there are many scientists - especially evolutionary biologists - who are very capable of discussing genecentrism in technical terms, there seems to be a nearly inescapable tendency even among themselves to use highly anthropomorphic language. Phrases like "selfish gene", "cooperative genes", and "A fit individual is one which works towards ensuring its alleles replicate." do nothing for understanding the actual biology of what is occurring. In fact, I submit that the terminology used in these cases is not only "inaccurate", but misleading, ambiguous, and obfuscatory. For these reasons, and others, I feel that the genecentric viewpoint - although having a place in evolution - is NOT the best and most accurate way of either looking at or describing natural selection. And may Darwin have mercy on us for wasting 288 posts on this subject.
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Fosdick  Suspended Member (Idle past 5521 days) Posts: 1793 From: Upper Slobovia Joined: |
Quetzal wrote: For these reasons, and others, I feel that the gene-centric viewpoint - although having a place in evolution - is NOT the best and most accurate way of either looking at or describing natural selection.
Those 288 posts were not wasted on me. Many good points were made on either side of the natural-selection argument. In general, the Quetzal v. Mod arguments were for us a fair representation of Gould v. Dawkins. Gould saw natural selection operating on the individual/group level of biological organization. Dawkins sees it instead as working at the gene/kin level. I think a great deal of clarity comes out of arguing these opposing views. And may Darwin have mercy on us for wasting 288 posts on this subject. As a scientist, I feel committed to viewing everything natural in terms of principles. If natural selection means anything at all, it must work according to biological principles, either known or unknown. So, as we argue the finer points of NS, we must necessarily attack each other’s principles, or lack thereof, to find the more durable explanation. Both Quetzal and Modulous express themselves so well that it is clear to me we have only one conclusion: Natural selection still shows disputed evidence of being at the scene of an evolutionary crime, because we can't agree on the scene. I think our only hope for agreeing on the meaning of natural selection, and agreeing on how evolution via natural selection works, is to focus on the specific definition of NS: Differential reproductive success amongst individuals of a population. Natural selection, in and of itself, does not mean sexual selection, random genetic drift, gene flows, or mutations; it means only that differential reproductive success amongst individuals of a population has taken place. Looking at NS as an effect, one might argue that sexual selection, random genetic drift, gene flows, and mutations could play their causal roles in NS. Or they might work independently to cause a microevolutionary event; NS may not always play a role. I would agree. But the bottom line, in my best estimation, is that NS associates causally with the redistribution of allele frequencies, because differential reproductive success will statistically do that, but it is only one of five known causes of allele-frequency redistribution. Therefore NS may also be an effect, suggesting a causal linkage to a microevolutionary event would need to be understood. To focus on the deeper meaning of NS, deeper than just “individual organisms being selected,” we have to focus on the evolution of allele frequencies. Genes, then, are where the NS action is. This seems to be obvious, at least to me, now in the modern times of molecular biology. ”HM
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Jazzns Member (Idle past 3932 days) Posts: 2657 From: A Better America Joined: |
I have a question:
the specific definition of NS: Differential reproductive success amongst individuals of a population. Natural selection, in and of itself, does not mean sexual selection,... Under what conditions do you ever concieve that sexual selection would NOT produce differential reproductive success? That would be the only case where you couldn't call sexual selection a type of natural selection right? Where mate preference is occurring yet everyone is still equally successful in reproduction. When would that EVER actually occur? Does that not directly contradict that concept of "preference"? Of course, biblical creationists are committed to belief in God's written Word, the Bible, which forbids bearing false witness; --AIG (lest they forget)
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crashfrog Member (Idle past 1488 days) Posts: 19762 From: Silver Spring, MD Joined: |
Congratulations, everybody!
Looking at NS as an effect, one might argue that sexual selection, random genetic drift, gene flows, and mutations could play their causal roles in NS. Or they might work independently to cause a microevolutionary event; NS may not always play a role. I would agree. But the bottom line, in my best estimation, is that NS associates causally with the redistribution of allele frequencies, because differential reproductive success will statistically do that, but it is only one of five known causes of allele-frequency redistribution. Therefore NS may also be an effect, suggesting a causal linkage to a microevolutionary event would need to be understood. To focus on the deeper meaning of NS, deeper than just “individual organisms being selected,” we have to focus on the evolution of allele frequencies. Genes, then, are where the NS action is. This seems to be obvious, at least to me, now in the modern times of molecular biology. 288 posts did absolutely nothing to stem HM's tide of pseudoscientific nonsense.
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Percy Member Posts: 22480 From: New Hampshire Joined: Member Rating: 4.8 |
This thread represents a profound failure on the part of the participating evolutionists (I do not except myself), because after nearly 300 messages in a thread whose purpose was to clearly define natural selection for Hoot Mon, his conclusion is that we're not exactly sure what it is and that it requires deeper study.
--Percy
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Fosdick  Suspended Member (Idle past 5521 days) Posts: 1793 From: Upper Slobovia Joined: |
Congratulations, every body!
And congratulations, froggie. That's the most substance I've seen in one of your posts since you reported finding E. Coli on your lawn. 288 posts did absolutely nothing to stem HM's tide of pseudoscientific nonsense. ”HM
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Fosdick  Suspended Member (Idle past 5521 days) Posts: 1793 From: Upper Slobovia Joined: |
Jazzns asked:
Non-random mating certaily would affect natural selection under most conditions, but not all of them. Why would every case of nonrandom mating necessarily cause differential reproductive success in a population if all individuals happen reproduced equally? Nonrandom mating does NOT automatically mean natural selection. Under what conditions do you ever concieve that sexual selection would NOT produce differential reproductive success? ”HM
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Fosdick  Suspended Member (Idle past 5521 days) Posts: 1793 From: Upper Slobovia Joined: |
Percy exhaust:
Maybe some of us are most interested in a deeper meaning of natural selection than Wikipedia can provide. This thread represents a profound failure on the part of the participating evolutionists (I do not except myself), because after nearly 300 messages in a thread whose purpose was to clearly define natural selection for Hoot Mon, his conclusion is that we're not exactly sure what it is and that it requires deeper study. ”HM
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crashfrog Member (Idle past 1488 days) Posts: 19762 From: Silver Spring, MD Joined: |
That's the most substance I've seen in one of your posts since you reported finding E. Coli on your lawn. I don't recall reporting that, but I don't believe I would be surprised to find E. coli out on my lawn, or anyone else's. I suspect it's just that, in your truly all-encompassing ignorance, you don't know what it means when a microbiologist talks about a "lawn."
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Fosdick  Suspended Member (Idle past 5521 days) Posts: 1793 From: Upper Slobovia Joined: |
I don't recall reporting that, but I don't believe I would be surprised to find E. coli out on my lawn, or anyone else's. I suspect it's just that, in your truly all-encompassing ignorance, you don't know what it means when a microbiologist talks about a "lawn."
Are you a microbiologist? I suspect you are not, since you didn't even know about E. coli conjugation. ”HM
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crashfrog Member (Idle past 1488 days) Posts: 19762 From: Silver Spring, MD Joined: |
Are you a microbiologist? Are you a "scientist" like you claimed to be? I'd like to read some of your published work, if so. (Do you save your nonsense just for us, or inflict it on the journals, too?) Can you pop me a few bibliographies? Email would be fine if you don't want to break anonymity.
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Fosdick  Suspended Member (Idle past 5521 days) Posts: 1793 From: Upper Slobovia Joined: |
crashfrog wrote:
I did what crashfrog requested of me by way of email. I did it in the spirit of friendship and with good intentions. Bad idea! Here is his email response:
Are you a "scientist" like you claimed to be? I'd like to read some of your published work, if so. (Do you save your nonsense just for us, or inflict it on the journals, too?) Can you pop me a few bibliographies? Email would be fine if you don't want to break anonymity. quote: Well, now I feel like Charlie Brown right after Lucy pulled the football away. I should have known better, since I already knew this boy has a real big wad in his underwear. ”HM
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crashfrog Member (Idle past 1488 days) Posts: 19762 From: Silver Spring, MD Joined: |
I'm sorry that you weren't able to recognize an overture intended for your benefit, and that you feel that it's appropriate to share private correspondence on a public forum without the sender's permission.
Edited by crashfrog, : No reason given.
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