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Author Topic:   What exactly is natural selection and precisely where does it occur?
Modulous
Member
Posts: 7801
From: Manchester, UK
Joined: 05-01-2005


Message 271 of 303 (391478)
03-25-2007 8:45 AM
Reply to: Message 262 by Percy
03-24-2007 7:44 PM


artificial selection
No, that's not as I say, that's as you say.
You just said that natural selection is a term with its own specific meaning. Are you recanting?
I'm not sure what is confusing about my definition, its the same as everyone else: Alleles which do well at promoting their own replication are selected to increase in frequency compared with alleles that don't do so well.
The only difference is that I don't agree that replacing the word Allele with 'individual' makes a great deal of sense and can lead to some paradoxes.
Only because you insist, and may God have mercy on poor Hoot Mon's confused soul. What is wrong with the simple and elegant contrast drawn between artificial and natural selection in the Wikipedia definition of artificial selection? No doubt you feel that it is inadequate and fails to address important distinctions, but there's the whole rest of the English language to help you get that across. There's no need to overburden these simple and useful terms - a word or phrase can only bear so much meaning, then it breaks and becomes useless.
The phrase has a meaning. Selection by artifice, but a certain kind of selection counts. It's perfectly simple. Farming and agriculture involves artificial selection. I don't see why that's difficult. That I consider artificial selection a well defined part of the exact same mechanism that is natural selection is hardly massively controversial.
Why do you want to put your personal ideas forward in a thread where some poor schnook just wants to know what, exactly, natural selection is. He didn't say he wants people to put forward their ideas about what it is, he wants to know exactly what it is.
And I have tried to explain what natural selection exactly is, and that artificial selection is actually (and surprisingly) a subset of natural selection. It certainly hasn't been my central point, and I think I only mentioned it as a side thought that you have gotten confused about. Others in this thread (Quetzal) have expressed understanding of the concept.
"Exactly" is not a synonym for infinite detail or nuance, nor is it an excuse for infinite digressions.
No it isn't. It is a synonym for all the available detail there is.
Quoting Wikipedia on artificial selection:
I agree with wikipedia.
This is precise, exact, easy to understand, and also disagrees with you about differential reproductive success preceding selection and about artificial selection being a subset of natural selection.
I don't think it inherently disagrees with me.
As Quetzal said earlier today (at least I think it was Quetzal), the terms are here, they've already got definitions
And I agree with those definitions. Natural selection has a precise meaning and we need to find it here. Artificial selection has a precise meaning and we can discuss it here if people wish.
I have been quite clear how Artificial Selection can be said to be a subset of Natural selection. If you want a more complete treatment of the subject I'm happy to spend more time on it, it's not vital though.

This message is a reply to:
 Message 262 by Percy, posted 03-24-2007 7:44 PM Percy has replied

Replies to this message:
 Message 273 by Percy, posted 03-25-2007 10:05 AM Modulous has replied

Modulous
Member
Posts: 7801
From: Manchester, UK
Joined: 05-01-2005


Message 272 of 303 (391481)
03-25-2007 8:53 AM
Reply to: Message 266 by Percy
03-24-2007 8:13 PM


Re: Hoot Mon's not entirely unreasonable position:
I composed this diagram to illustrate how you have it backwards with respect to the order of natural selection and differential reproductive success.
I think you are confused about what was being said.
Let me try again.
To get natural selection you need to have a population with differential reproductive success. If there is no differential reproductive success there is no natural selection. You surely agree with that?
Thus what I was saying was:
Differential reproductive success + instructions leads to natural selection.
A population that has been 'paused' can still have differential reproductive capability. If we know that there will be differential reproductive success and there are instructions in play we can predict that natural selection will follow.
That's all I was saying.
Naturally if we know that natural selection will take place then we can likewise deduce there are instructions and differential reproductive success. However, that is a backwards way of trying to understand natural selection.
To stay with the pool analogy, Hoot Mon has told everyone what a great swimmer he is, then has dived into the deep end where he struggles to keep his head above water while disdaining all suggestions that perhaps he might want to spend a little time in shallower water first.
Indeed - you see him struggling to keep his head above the water. I see him needing to refine his strokes while he his laughing at the kiddies in the shallow end.

This message is a reply to:
 Message 266 by Percy, posted 03-24-2007 8:13 PM Percy has replied

Replies to this message:
 Message 279 by Fosdick, posted 03-25-2007 1:44 PM Modulous has not replied
 Message 280 by Percy, posted 03-25-2007 2:54 PM Modulous has replied

Percy
Member
Posts: 22389
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 273 of 303 (391484)
03-25-2007 10:05 AM
Reply to: Message 271 by Modulous
03-25-2007 8:45 AM


Re: artificial selection
Modulous writes:
No, that's not as I say, that's as you say.
You just said that natural selection is a term with its own specific meaning. Are you recanting?
No, you just phrased it oddly, as if my definition agreed with the definition you had just given, and I don't agree with that definition. As I said in the following words that you didn't quote, "When you describe natural selection I barely recognize it, and the same for artificial selection."
The only difference is that I don't agree that replacing the word Allele with 'individual' makes a great deal of sense and can lead to some paradoxes.
Every approach you take to defining something with as much variety as evolution is going to run into problems. It isn't that your view has fewer problems, it's that you personally feel more comfortable with those problems than the ones from a phenotypic perspective, and further, you think everyone else should feel the same way you do about it.
Our mutual positions are not symmetric. I think both perspectives have merit and present certain advantages depending upon context, while you just think yours is superior and the other worth denigrating.
The phrase has a meaning. Selection by artifice, but a certain kind of selection counts. It's perfectly simple. Farming and agriculture involves artificial selection. I don't see why that's difficult. That I consider artificial selection a well defined part of the exact same mechanism that is natural selection is hardly massively controversial.
Of course it's not controversial. I agree with you. But the statements from you I've objected to haven't phrased it that way. You're actually changing what you're saying to make it sound more reasonable. If you'll recall, earlier you said that natural selection isn't natural and artificial selection isn't artificial. It was like you were purposefully trying to obfuscate. If you had instead merely said that one way of looking at artificial selection is as a subset of natural selection there would have been no argument, because I would have agreed with you. Where we differ is that you think that not only can artificial selection be viewed this way, but that it *should* be viewed this way, and that you're going to tell poor people like Hoot Mon that it is viewed this way, despite the fact that it isn't. As Quetzal has said, and if I hadn't said it first I would have, these terms, for better or worse, are already defined.
"Exactly" is not a synonym for infinite detail or nuance, nor is it an excuse for infinite digressions.
No it isn't. It is a synonym for all the available detail there is.
I think that if you look it up you'll find that "exactly" is not a synonym for "all available detail. In a thesaurus you'll actually find "precise" listed, while, amazingly enough, your "all the available detail" is conspicuously absent. Exactly is not a synonym for "brain dump."
Like all words, exactly has more than one definition, and like all words it is nuanced by context. You're dumping detail on Hoot Mon that he can't handle. Even if he had instead titled this thread, "What is all the available detail on natural selection?", once it became evident that he was struggling with the material it would have been appropriate to back off on the detail. You're not doing that, but that's okay because I understand that you think he's handling the detail just fine. I wish I'd had teachers like you - even when I was dead wrong I'd have gotten an A-. On second thought, I take it back. I'd have gotten good grades but learned little.
Quoting Wikipedia on artificial selection:
I agree with wikipedia...I don't think it inherently disagrees with me.
Well, no you don't agree with Wikipedia, actually, and while it doesn't "inherently disagree" with you, if by that you mean it doesn't have a sentence saying, "Artificial selection is not a subset of natural selection," it clearly doesn't define artificial selection in this way, does it? The Wikipedia portion that I quoted defines artificial selection by way of contrast with natural selection. It doesn't define it as a subset. Further down the Wikipedia article notes that many biologists view some forms of what might be called artificial selection as part of natural selection, such as domestication, but nowhere in the article does it say or even imply generally that, "Artificial selection is a subset of natural selection."
It isn't that I disagree with you. I share your view that artificial selection can be thought of as a subset of natural selection. All I'm saying is that while this is true conceptually, that's not the actual definition of the term, and for better or worse that's the definition we've been left with historically, and to just claim that "Artificial selection is a subset of natural selection" without any qualifiers or setting of context or explaining why you're saying this when easily located definitions on the web do not say this, is just being misleading.
And I agree with those definitions. Natural selection has a precise meaning and we need to find it here. Artificial selection has a precise meaning and we can discuss it here if people wish.
Except you're not discussing it. You're just looking at the definitions and saying, "I agree with this." This leave me saying, "What you just said disagrees with this definition in these particular ways, how can you say that?" If you again just reply, "I agree with this," which is what you're doing, then there's really no discussion going on, not from your side anyway.
Omigod, gotta go, no time to proofread, sorry, hope this makes sense...
--Percy

This message is a reply to:
 Message 271 by Modulous, posted 03-25-2007 8:45 AM Modulous has replied

Replies to this message:
 Message 275 by Modulous, posted 03-25-2007 10:55 AM Percy has replied

Quetzal
Member (Idle past 5871 days)
Posts: 3228
Joined: 01-09-2002


Message 274 of 303 (391489)
03-25-2007 10:38 AM
Reply to: Message 267 by JustinC
03-24-2007 8:37 PM


Re: genecentrism revisted
But how does one define fitness? It can't just be fecundity, because if you give birth to hundred weaklings (metaporical sense) their all sure to die and you're sure not to have any descendents so any trait that you had that increased your reproductive success will die out.
Right. I certainly haven't read anywhere that fitness is "just fecundity", so I'm not sure where you got that. Unfortunately, we're coming up to the end of this thread, so a long digression here may be counterproductive. Without getting into a very long discussion, suffice for the purposes of this thread I define fitness as the average lifetime contribution of individuals posessing a particular genotype to the population after one (or more) generations. In other words, not just the numbers of offspring that an individual can pump out, but the number of offspring carrying a particular genotype that themselves live to reproduce. So, simplistically, fitness of a genotype = (average fecundity) X (fraction surviving).
Obviously, there is a lot of detail and nuance (relative vs absolute fitness, for instance) that I'm leaving out, but that's the gist, and probably sufficient for this particular discussion.

This message is a reply to:
 Message 267 by JustinC, posted 03-24-2007 8:37 PM JustinC has not replied

Modulous
Member
Posts: 7801
From: Manchester, UK
Joined: 05-01-2005


Message 275 of 303 (391490)
03-25-2007 10:55 AM
Reply to: Message 273 by Percy
03-25-2007 10:05 AM


Re: artificial selection
Our mutual positions are not symmetric. I think both perspectives have merit and present certain advantages depending upon context, while you just think yours is superior and the other worth denigrating.
Its certainly worth pointing out the problems with it. Gould goes to great length to try and point out the problems with genecentrism, and Dawkins does the opposite.
If you'll recall, earlier you said that natural selection isn't natural...
I've never said that.
artificial selection isn't artificial
Where artificial means unnatural.
It was like you were purposefully trying to obfuscate. If you had instead merely said that one way of looking at artificial selection is as a subset of natural selection there would have been no argument, because I would have agreed with you.
That's what I have been saying a lot of. I've also said that not all 'selection that is natural' is natural selection. It's not obfuscative at all, its quite straightforward discussion on how things are related to one another.
Where we differ is that you think that not only can artificial selection be viewed this way, but that it *should* be viewed this way
Only that it should be viewed that way when seeking a full understanding of natural selection. There are plenty of times when it isn't necessary or wise to view it this way.
As Quetzal has said, and if I hadn't said it first I would have, these terms, for better or worse, are already defined.
Which has been my point. Natural selection is more than selection that is natural. It means something.
We're here to discuss that very thing.
Well, no you don't agree with Wikipedia, actually
I think I know what I agree with.
The Wikipedia portion that I quoted defines artificial selection by way of contrast with natural selection.
And indeed - I agree. That doesn't mean they are mutually exclusive!
I think that if you look it up you'll find that "exactly" is not a synonym for "all available detail. In a thesaurus you'll actually find "precise" listed, while, amazingly enough, your "all the available detail" is conspicuously absent. Exactly is not a synonym for "brain dump."
Did you check what precise means? You might find for example: Clearly, fully, and sometimes emphatically expressed.
Like all words, exactly has more than one definition, and like all words it is nuanced by context. You're dumping detail on Hoot Mon that he can't handle.
Yes, I'm clear on what you think. I don't think that, that's why I'm happy doing it. If I thought he couldn't handle it I wouldn't. However- I've hardly replied to Hoot Mon in this thread. My first reply was to crashfrog and I mostly ignored Hoot Mon's responses. I spoke with AZPaul and Quetzal. It wasn't until much later that I really responded in any detail to Hoot Mon. You should probably bare that in mind - I was just trying to explain what Hoot Mon was trying to explain to other people to those people. I wasn't trying to explain genecentrism to Hoot Mon - he already seemed to have a grasp of that.
even when I was dead wrong I'd have gotten an A-. On second thought, I take it back. I'd have gotten good grades but learned little.
Assuming Hoot Mon is dead wrong, your right. I don't think he is. He raises many of the arguments that have flown about between people like Gould and Dawkins. He has gotten things wrong and I've attempted to teach him some of those things, but I've not corrected him where he has been right.
we've been left with historically, and to just claim that "Artificial selection is a subset of natural selection" without any qualifiers or setting of context or explaining why you're saying this when easily located definitions on the web do not say this, is just being misleading.
When I originally mentioned it I provided the context. Surely you can look back and see that context?
Except you're not discussing it. You're just looking at the definitions and saying, "I agree with this." This leave me saying, "What you just said disagrees with this definition in these particular ways, how can you say that?" If you again just reply, "I agree with this," which is what you're doing, then there's really no discussion going on, not from your side anyway.
I can't explain it any further. I've provided my rationale for considering art. selection as a subset for nat. selection. Either you want me to expand on that or explain certain things, or you don't. That means art. selection is its own thing.
I have it in a book somewhere, and I'll make a new thread of it if you like.

This message is a reply to:
 Message 273 by Percy, posted 03-25-2007 10:05 AM Percy has replied

Replies to this message:
 Message 281 by Percy, posted 03-25-2007 3:02 PM Modulous has not replied

Fosdick 
Suspended Member (Idle past 5499 days)
Posts: 1793
From: Upper Slobovia
Joined: 12-11-2006


Message 276 of 303 (391491)
03-25-2007 11:02 AM
Reply to: Message 262 by Percy
03-24-2007 7:44 PM


Re: clarification
Why do you want to put your personal ideas forward in a thread where some poor schnook just wants to know what, exactly, natural selection is. He didn't say he wants people to put forward their ideas about what it is, he wants to know exactly what it is. "Exactly" is not a synonym for infinite detail or nuance, nor is it an excuse for infinite digressions. He wants precision, which is the opposite of the muddle of confusing detail we're in now. Quoting Wikipedia on artificial selection...
You can awlays tell when a guy's shorts are on fire when he resorts to name calling and Wikipedia for establishing his credibility.
”HM

This message is a reply to:
 Message 262 by Percy, posted 03-24-2007 7:44 PM Percy has not replied

Replies to this message:
 Message 277 by crashfrog, posted 03-25-2007 11:50 AM Fosdick has not replied

crashfrog
Member (Idle past 1466 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 277 of 303 (391494)
03-25-2007 11:50 AM
Reply to: Message 276 by Fosdick
03-25-2007 11:02 AM


Re: clarification
You can awlays tell when a guy's shorts are on fire when he resorts to name calling and Wikipedia for establishing his credibility.
If you believe the information at Wikipedia is inaccurate, why don't you go over there and fix it?

This message is a reply to:
 Message 276 by Fosdick, posted 03-25-2007 11:02 AM Fosdick has not replied

Quetzal
Member (Idle past 5871 days)
Posts: 3228
Joined: 01-09-2002


Message 278 of 303 (391496)
03-25-2007 12:06 PM
Reply to: Message 269 by Modulous
03-25-2007 8:23 AM


Re: genecentrism revisted
I am still waiting for a decent individualist account of social insect selection.
I wasn't aware that this was a challenge. I know that it was discussed earlier, but I didn't jump in there simply because that wasn't part of what I was arguing with you about. Unfortunately, as I mentioned to Justin (were you aware you had a gencentrist supporter on this thread?), we're coming to the end of the thread. Rather than move off into yet another side discussion, we should be summing up. I'd be happy to discuss this particular issue elsewhere, however.
Mod writes:
Q writes:
Not that I necessarily support Gould, but why would the questions I asked be based on a misunderstanding of genecentrism?
They are the kinds of questions those that don't understand genecentrism ask.
This doesn't answer the question, Mod. Come on, you can do better than that. Why are the questions bogus? How do the questions demonstrate a lack of understanding? You seem to be equating "disagreement" with "lack of knowledge". The two are not synonymous. I understand genecentrism. I simply don't agree with the approach. Merely denigrating the phenotype viewpoint doesn't serve to validate the "superiority" of genecentrism. Look, you're not Dawkins, and I'm not Gould. That being the case, I would have thought we could have a discussion of this topic without the personality aspects they bring (brought) to the table. It doesn't appear you agree. Pity.
I understand why you're side-stepping the fitness questions. It is one of the key problems with genecentrism. The viewpoint provides a nice, very useful metaphor for looking at evolution. It absolutely bites rocks when you're trying to look at natural selection in isolation. As you've demonstrated in this thread, under genecentrism the two concepts simply cannot be divorced from each other. It makes absolutely NO distinction between selection (NS) and adaptive response (evolution). It can't. It isn't set up to be able to do this. It is an evolutionary metaphor. Justin mentioned Ancestor's Tale, and I would submit River Out of Eden as well, as examples of why genecentrism and fitness are incompatible concepts. This does NOT mean that genentrism is "wrong". It isn't. It does mean, however, that there are questions which it simply doesn't (or isn't designed to) address effectively. One of them being the topic of this thread.
Mod writes:
Q writes:
In other words, all I'm asking you to do is explain the implications of fitness calculations based on the genecentric viewpoint. You can call individual selection "inferior" all day long, but you still need to address the questions directly if you want this categorization to be taken seriously.
Indeed - and the questions were answered.
Where? Can you point to the post(s) where you discussed fitness in the context of genecentrism? I must have missed it/them. If I believed you had already "answered" the questions, I wouldn't have posted them - we'd already be discussing those answers. I'm not some ignorant creationist you can blow off with this type of one-liner.
Mod writes:
Q writes:
Wow, this smacks of genetic determinism. Is that really the position you wish to advocate? I will absolutely guarantee you that Dawkins doesn't hold this view. Maybe you should expand your answer a bit? For clarity, I mean.
I have. The point I've made is that 'fit' individuals don't necessarily get naturally selected. That is why the gene view is better.
What? This makes no sense, and certainly doesn't clarify your previous response that I wanted you to expand upon. Here it is again, for reference:
Mod, in post 256 writes:
A fit individual is one which works towards ensuring its alleles replicate.
This is genetic determinism. I don't think you advocate this (or do you?). This is what I questioned you about. Your statement "fit individuals don't get naturally selected" doesn't even relate to the previous statement. I'm not trying to trap you here - I really am trying to understand what you're talking about. I'm not getting it, and so asked you to explain. Rather than explain, you pumped out an unrelated one-line soundbite. What's wrong, Mod? This isn't like you.
Mod writes:
Q writes:
Do you consider behavior a phenotypical trait that has a fitness implication? If not, why not? If so, how does that square with genecentrism?
Naturally a phenotypical trait has fitness implications. It squares with genecentrism when that phenotypical trait is caused by the genes. When it is not caused by genes it is irrelevant to natural selection.
This doesn't answer the question I asked. Or at best, only answers it partly. Focus on behavior, please.
In addition, you've once again pointed up the main problem with genecentrism: the inability to separate natural selection from evolution. If you substitute the latter word in the last sentence you wrote, then I would agree with you. However, as written, the sentence is simply wrong.
Mod writes:
Q writes:
Wait a second. This doesn't really make sense to me. Please explain what you think the relationship between selection and fitness might be? Perhaps that will clarify your position for me. 'Cause this appears at first glance to be moving WAY beyond any definition of fitness I've ever encountered.
You are asking about individual fitness. Obviously since I do not believe that individuals get selected - the two concepts won't gel together (which is essentially my point).
No, I'm not. I asked you to explain the relationship between selection and fitness in the context of genecentrism. Of course, you can also take the tack that "fitness" is meaningless in that context, but in which case you've got a pretty tough row to hoe.
They work together by creating good (or in many cases, bad) replication machines. In the environment where the sickle cell genes work together well (and in concert with other genes and across the whole population), they do so because other alleles cannot create machines that hold off malaria as well.
This points up another problem I have with the utility of the genecentric viewpoint. Proponents are apparently incapable of describing anything without recourse to (IMO) confusing, ambigious, and misleading anthropomorphic language. Can you possibly provide a more technically sound response to my question - leaving off the metaphors and anthropomorphisms? Thanks.
Mod writes:
Q writes:
...you have not been able to divorce the measurement of a gene's fitness from the measurement of the organism's fitness.
I wouldn't dream of doing so. An organism may be fit for extra-genetic reasons (such as cybernetic eyes), or an organsim may be fit for genetic reasons (pretty feathers). Since an organism's 'fitness' is not inherently tied into the genes they cannot be the ultimate entity subject to natural selection.
I understand what you meant in the last sentence, even though you wrote it like you were agreeing with me at last - I know that's not the case. Be that as it may, this doesn't address my point. The claimed utility of genecentrism is that it provides a better explanation of what happens under natural selection than does the phenotypical viewpoint. However, if genecentrism is incapable of measuring or discussing fitness without recourse to measures of fitness of the individual organism, then I submit that all it's doing is adding an additional level of abstraction that doesn't advance our understanding. In fact, you've as much as said that fitness is an organismal (read, phenotypical) characteristic, but that anything that isn't genetic is ignored under genecentrism.
Mod, I don't really understand what the problem is on this thread. You are normally one of my favorite posters: well read, well written, and incisive. You apparently don't consider me worth making that effort. If you are unable to provide more than off-the-cuff one-liners - which moreover are in essence no more than simple restatements of your position - in response to what I write here, I think I better simply bow out of this thread and let you persue your side discussion with Percy in the remaining few posts. Hopefully you're just having an off thread.
Edited by Quetzal, : Fixed bad ubb coding

This message is a reply to:
 Message 269 by Modulous, posted 03-25-2007 8:23 AM Modulous has replied

Replies to this message:
 Message 283 by Modulous, posted 03-25-2007 3:54 PM Quetzal has not replied

Fosdick 
Suspended Member (Idle past 5499 days)
Posts: 1793
From: Upper Slobovia
Joined: 12-11-2006


Message 279 of 303 (391507)
03-25-2007 1:44 PM
Reply to: Message 272 by Modulous
03-25-2007 8:53 AM


Re: Hoot Mon's not entirely unreasonable position:
Regarding the exchange between Percy and Mod:
To stay with the pool analogy, Hoot Mon has told everyone what a great swimmer he is, then has dived into the deep end where he struggles to keep his head above water while disdaining all suggestions that perhaps he might want to spend a little time in shallower water first.
Indeed - you see him struggling to keep his head above the water. I see him needing to refine his strokes while he his laughing at the kiddies in the shallow end.
No, I'm only struggling a little here in the deep end, because I'm really snorkeling with my water wings and flippers. I seriously doubt if anyone here is entirely free of struggles to apprehend the true meaning of natural selection. There are plenty of good reasons to be confused about what it is, exactly, and precisely where it occurs. Please consider this example.
Richard Dawkins, in his The Ancestor’s Tale (2005, pp. 424-330), singles out the class Bdelloidea of the phylum Rotifera for an examination of how it may have evolved and may continue to evolve. The bdelloid rotifer has adapted to a parthenogenetic form of asexual reproduction, instead of the usual sexual reproduction that mixes male and female alleles together. In the case of bdelloid rotifers, all the genes passed on generationally come from females only, because there are no males in the population. So Dawkins wonders:
quote:
Think of how different evolution must be for the bdelloid rotifer. Far from being swamped into normalcy but the gene pool, they don’t even have a gene pool. The very idea of a gene pool has no meaning if there is no sex.
Certainly. And so the only way a bdelloid rotifer population could have evenly distributed reproductive success amongst its individuals, or a disturbance therein, is for all females to reproduce equally, which probably doesn’t always happen. And even then there is no gene pool to be the object of natural selection, if that's what really goes on with these all-girl rotifers. And so Dawkins wonders:
quote:
Natural selection presumably takes place among the bdelloids, but it must be a very different kind of natural selection from the one the rest of the animal kingdom is accustomed to.
Indeed, since the rule of differential reproductive success is matriarchal to the extreme. And it presents a nice exception to the concept, one that casts doubt on the firmness of our understanding of natural selection.
While Dawkins finds the bdelloids an interesting study of evolution, possibly by way of natural selection but without a gene pool, he goes on to say:
quote:
Where there is sexual mixing of genes, the entity that is carved into shape by natural selection is the gene pool. Good genes tend statistically to help the individual bodies in which they find themselves to survive. Bad genes tend to make them die. In sexually reproducing animals, its is the deaths and reproduction of individual animals that constitute the immediate selective event, but the long-term consequence is a change in the statistical profile of genes in the gene pool. So, it is the gene pool, as I say, that is the object of the Darwinian sculptor’s attention.
Maybe both sides are right on the question of where natural selection occurs: indiviual vs. gene. But are these "immediate" and "long-term" stipulations always enough to place natural selection at the scene of an evolutionary crime?
”HM

This message is a reply to:
 Message 272 by Modulous, posted 03-25-2007 8:53 AM Modulous has not replied

Percy
Member
Posts: 22389
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 280 of 303 (391512)
03-25-2007 2:54 PM
Reply to: Message 272 by Modulous
03-25-2007 8:53 AM


Re: Hoot Mon's not entirely unreasonable position:
Modulous writes:
I think you are confused about what was being said.
No, I'm not confused. You go on:
Modulous writes:
Let me try again.
To get natural selection you need to have a population with differential reproductive success. If there is no differential reproductive success there is no natural selection. You surely agree with that?
Yes, I know that's what you were saying. And it's wrong because it's backward. Differential reproductive success is evidence that natural selection has taken place. Differential reproductive success is not a cause but a result of natural selection.
Hoot Mon's earlier confused questions about whether perhaps natural selection applies to lineages rather than to individuals come directly from this misconceived way of characterizing natural selection. He keeps asking where, exactly, natural selection happens, and your answers have left him floundering around looking for a place where natural selection happens, and finally concluding that it's just a high level overview of the process. It's why he keeps drifting back to saying that natural selection equals evolution. It is evolution which is the true high-level term for the concept, not natural selection.
My diagram illustrates where, exactly, natural selection happens. Naturally some accompanying text renders it more comprehensible, but this is just you and me talking and so that may not be necessary, but I'd be happy to clarify to any extent you desire.
This is from Wikipedia:
Wikipedia on natural selection writes:
Darwin thought of natural selection by analogy to how farmers select crops or livestock for breeding, which he called artificial selection.
So in artificial selection, differential reproductive success occurs only after and as a direct result of the farmer selecting crops or livestock for breeding. And Darwin used artificial selection as a way of introducing the broader concept of natural selection. Your gene-centric view has caused you to not only lose sight of this, but even to call it wrong and backwards.
--Percy

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 Message 272 by Modulous, posted 03-25-2007 8:53 AM Modulous has replied

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 Message 282 by Modulous, posted 03-25-2007 3:11 PM Percy has not replied

Percy
Member
Posts: 22389
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 281 of 303 (391514)
03-25-2007 3:02 PM
Reply to: Message 275 by Modulous
03-25-2007 10:55 AM


Re: artificial selection
Hi Modulous,
Quetzal concluded his last post with this:
Quetzal in Message 278 writes:
Mod, I don't really understand what the problem is on this thread. You are normally one of my favorite posters: well read, well written, and incisive. You apparently don't consider me worth making that effort. If you are unable to provide more than off-the-cuff one-liners - which moreover are in essence no more than simple restatements of your position - in response to what I write here, I think I better simply bow out of this thread and let you persue your side discussion with Percy in the remaining few posts. Hopefully you're just having an off thread.
I sort of feel the same way. We're not getting anywhere, I feel like I'm being treated like I don't deserve a straight answer, so I'm just going to bow out, too.
AbE: I guess I should have made clear that I agree with everything else Quetzal said, too. You're knowledgeable and a master of clear expression. I can't figure out why we've been unable to generate any momentum toward a mutual understanding.
--Percy
Edited by Percy, : Add clarification.

This message is a reply to:
 Message 275 by Modulous, posted 03-25-2007 10:55 AM Modulous has not replied

Modulous
Member
Posts: 7801
From: Manchester, UK
Joined: 05-01-2005


Message 282 of 303 (391516)
03-25-2007 3:11 PM
Reply to: Message 280 by Percy
03-25-2007 2:54 PM


Re: Hoot Mon's not entirely unreasonable position:
Differential reproductive success is evidence that natural selection has taken place. Differential reproductive success is not a cause but a result of natural selection.
I gave you an example scenario where there was differential reproductive success and no natural selection. If you have differential reproductive sucesss you might also have natural selection, but you need some kind of hereditary instruction set as well.
Hoot Mon's earlier confused questions about whether perhaps natural selection applies to lineages rather than to individuals come directly from this misconceived way of characterizing natural selection.
Not at all! Quite the contrary - lineage selection is a position that he got from Gould - a a selection type I have argued against as being natural selection. Group selection is not natural selection.
He keeps asking where, exactly, natural selection happens, and your answers have left him floundering around looking for a place where natural selection happens, and finally concluding that it's just a high level overview of the process
He isn't concluding its a high level overview from me. I have been arguing a reductionist point of view which shuns the 'hierarchy theory' that Gould was a fan of.
It's why he keeps drifting back to saying that natural selection equals evolution.
Which nearly correct. If you have natural selection, you have evolution - by definition! However, he also says that evolution does not equal natural selection - so though he might use the term, he truly isn't actually saying the one is equal to the other.
So in artificial selection, differential reproductive success occurs only after and as a direct result of the farmer selecting crops or livestock for breeding. And Darwin used artificial selection as a way of introducing the broader concept of natural selection.
And that is exactly what I agree is artificial selection.
Your gene-centric view has caused you to not only lose sight of this, but even to call it wrong and backwards.
It really hasn't. It just allows me to include the process of artificial selection within the paradigm of natural selection. What is the most successful bird on the planet? The chicken! Why? Because man's genes benefit by propagating chicken genes. Not all chicken genes are happy about this, since they are made extinct, but some chicken genes have flourished in this niche.

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 Message 280 by Percy, posted 03-25-2007 2:54 PM Percy has not replied

Replies to this message:
 Message 285 by Fosdick, posted 03-25-2007 7:43 PM Modulous has not replied

Modulous
Member
Posts: 7801
From: Manchester, UK
Joined: 05-01-2005


Message 283 of 303 (391518)
03-25-2007 3:54 PM
Reply to: Message 278 by Quetzal
03-25-2007 12:06 PM


Re: genecentrism revisted
Why are the questions bogus? How do the questions demonstrate a lack of understanding? You seem to be equating "disagreement" with "lack of knowledge".
The questions are not bogus. If you understood the genecentric view you'd not be asking those questions (since the answer would be apparant). Maybe they were just for rhetorical purpose, to demonstrate disagreement.
Merely denigrating the phenotype viewpoint doesn't serve to validate the "superiority" of genecentrism.
I don't think I am denigrating it. I am simply saying that one comes across certain paradoxes when looking at the individual approach. Oftentimes it is a perfectly functional approach and have said so quite a lot.
I understand why you're side-stepping the fitness questions. It is one of the key problems with genecentrism. The viewpoint provides a nice, very useful metaphor for looking at evolution.
I didn't bypass the fitness questions. I answered them, I said you'd measure a genes fitness in replications per time period. An individuals fitness is difficult to calculate because it depends on what we are saying it is fit for. Reproducing? Surviving? Growing? All of these things?
It makes absolutely NO distinction between selection (NS) and adaptive response (evolution).
Well of course it makes the distinction. Selection is the process of alleles replicating more than others. Evolution is the resulting change in allele frequencies. Evolution can happen without selection. Mutation events for example. Selection is just one way for allele frequencies to change, one of many that occur in biology.
Where? Can you point to the post(s) where you discussed fitness in the context of genecentrism?
Message 156,
quote:
One simply has to calculate how well that allele functions towards causing its own replication. I'd imagine replications per [time period] or per generation would be a good way of realistically measuring it.
A fit individual is one which works towards ensuring its alleles replicate.
This is genetic determinism.
No, genetic determism is the belief that an individual's behaviour and body is soley (or mostly) determined by the genes. I don't think that is the case. You asked what a fit individual was, in context of genes and I answered thusly. If you want to know some other fitness measurement, then we can discuss this too sometime. A fit individual could be one that lives the longest, if you'd like - but that is not a fit individual in gene terms.
This is what I questioned you about. Your statement "fit individuals don't get naturally selected" doesn't even relate to the previous statement.
An individual who is fit because of some acquired characteristic - such as bionic eyes - may well replicate his genes more than somebody who does not have this acquired characteristic. This is not natural selection though. The genes don't determine perfectly the phenotype, they are not totally linked. So an individual might be fitter than his genes would make him. His reproductive success is not genetically related and so it isn't natural selection.
Do you consider behavior a phenotypical trait that has a fitness implication?
Behaviour can be an extension of a phenotypical trait (ie a brain structure that leads to a certain behaviour). And yes, it has a fitness implication.
If so, how does that square with genecentrism?
Genes that cause behaviours in their vehicles that helps those vehicles replicate those genes will be positively selected for.
You are asking about individual fitness. Obviously since I do not believe that individuals get selected - the two concepts won't gel together (which is essentially my point).
No, I'm not. I asked you to explain the relationship between selection and fitness in the context of genecentrism.I asked you to explain the relationship between selection and fitness in the context of genecentrism.
You said:
Quetzal writes:
Is the fitness of an organism in its particular environment dependent solely on genetics, or is fitness a phenotypical characteristic?
The relationship between selection and fitness is plain in genecentism. A gene that replicates itself (or helps replicate copies of itself) is fit - the more it can replicate and the faster (compared to its alleles) the fitter. Fit genes tend to be selected to replicate more. They don't always replicate more, but the tendency is for fit genes to do so.
The fitness of an organism is not something that means anything. Fitness to do what? Fitness to aid its genes in replicating? Its the only thing that I can draw out of it. The reason it doesn't mesh is because sometimes that fitness is not caused by a hereditary trait. Since natural selection is only selecting hereditary traits, a fit individual aiding its genes isn't going to pass that useful trait on, so there is no natural selection going on.
Assuming the trait is randomly acquired, its positive effect on the lucky individual's genes is cancelled about the positive effect on the competitor's genes too (and thus competetive alleles). The tendency for this kind of selection is towards not altering the gene frequencies. Any deviation from altering the gene frequencies is just a random drift of sorts.
This is not natural selection yet the individual is being positively selected for.
I understand what you meant in the last sentence, even though you wrote it like you were agreeing with me at last - I know that's not the case. Be that as it may, this doesn't address my point. The claimed utility of genecentrism is that it provides a better explanation of what happens under natural selection than does the phenotypical viewpoint. However, if genecentrism is incapable of measuring or discussing fitness without recourse to measures of fitness of the individual organism, then I submit that all it's doing is adding an additional level of abstraction that doesn't advance our understanding.
Hopefully now you understand that the fitness of an allele can be explained without reference to individuals yet individual's fitness is difficult to discuss without reference to genes. A gene's fitness is measured in replications per x and compared with its alleles' replications per x.
Edited by Modulous, : No reason given.

This message is a reply to:
 Message 278 by Quetzal, posted 03-25-2007 12:06 PM Quetzal has not replied

Modulous
Member
Posts: 7801
From: Manchester, UK
Joined: 05-01-2005


Message 284 of 303 (391523)
03-25-2007 4:29 PM


Another paradox from individual selection
Well - it's time to sum up. What is natural selection, and where does it occur? It's a fine question and trying to answer it means we have to answer other questions along the way - a fruitful discourse!
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.
Here is my view of that. Most of the time, what is in the interest of an individual is in the interest of a gene, and visa versa. This is not always the case though, so when we look at selection we need to be careful. What if a gene could find a way of replicating faster - to the detriment of the individual? The frequencies of this allele will rise, but the individuals possessing it will be less reproductively fit than those that don't. They have less babies, but the allele spreads and spreads and spreads. Pretty soon most of the population has this allele. The individuals are becoming less fit by the generation! How are they being positively selected for!?
The answer lies in genecentric vision. Segregation distorters exploit meiotic drive. The Mouse t-haploytpe is an example of one. Normally 50% of your genes are passed on at reproduction. However, some genes cheat! They manage to ensure that they will be passed on as much as 95% of the time. They are usually detrimental to the individual who has them, and fatal to those that have two of them. However because the victims don't need to make as many babies to ensure the gene is passed on...it doesn't matter.
Natural selection shaped these genes, and natural selection ensured that they flourished (until the deme goes extinct, which is not unheard of).
One misunderstanding that I think might have happened is that the genecentric view ignores the individual entirely. This is not so. One way for allele frequencies to shift is for those alleles to be selected. However, there is more than one way for a gene to be selected. One way is for it to be good at cooperating with other genes in making vehicles which are good at replicating it. Another way is to 'cheat' as in Intragenomic conflict.
Cheating is a short term strategy - since in the long run the survival penalty will outweigh the replication bonus.
Genes act to either directly replicate themselves more than their alleles (cheating) or do so by building good vehicles that ensure replication or by building good vehicles that build good vehicles (houses, dams, shells, webs) that aid in replication. We could say spider webs get selected based on how well they catch flies and allow the spider to do its other tasks, but that would miss the real selection at the spider level which is getting selected for building good webs (after all, some webs are good by accident), but we would miss the natural selection at the gene level which is selecting genes that work well together to create spiders that create webs.
Finally and once again: the individual level is usually good enough because what is good for the individual is often good for the gene. There are some exceptions to this. There are some things which are bad for the individual but good for the gene. Since evolution is about allele frequencies, this is what is really being selected. WE could talk about change in phenotypes over time, but that would only be the broad strokes of evolution not the real thing (missing leg frequency probably increases in time of war, but that isn't evolution).
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.

Replies to this message:
 Message 286 by Fosdick, posted 03-25-2007 8:13 PM Modulous has not replied

Fosdick 
Suspended Member (Idle past 5499 days)
Posts: 1793
From: Upper Slobovia
Joined: 12-11-2006


Message 285 of 303 (391548)
03-25-2007 7:43 PM
Reply to: Message 282 by Modulous
03-25-2007 3:11 PM


Re: Hoot Mon's not entirely unreasonable position:
Not all chicken genes are happy about this, since they are made extinct, but some chicken genes have flourished in this niche.
You can tell the ones with the chicken genes”they're all clucking down at the shallow end of the pool.
I simply do not understand why Percy et al. are so angry with you, Mod. Aren't we just having a rigorous scientific debate? I like debating with most of thse guys. A few of them would like to insult me. But who needs to get angry over it? I've been held up for ridicule, called names like "schnook," flamed and abused, but I ain't angry; I'm happy to see more clearly what I am dealing with. And I don't mind a little dirty fighting in the alleys.
”HM

This message is a reply to:
 Message 282 by Modulous, posted 03-25-2007 3:11 PM Modulous has not replied

Replies to this message:
 Message 287 by crashfrog, posted 03-25-2007 8:36 PM Fosdick has not replied

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