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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 256 of 303 (391358)
03-24-2007 6:25 PM
Reply to: Message 254 by Quetzal
03-24-2007 4:41 PM


genecentrism revisted
Yes, I know you've said that repeatedly. I'm not sure you've actually gone so far as to demonstrate that contention, although you may believe you have.
It might be difficult to demonstrate given the medium. However, I can highlight why one model is inferior to another by showing its weaknesses and how another model does not share those weaknesses.
I have only touched on the issues of course, once again the medium prevents full intercourse. Gould and Dawkins wrote lengthily about their views and reference to them has been made for better treatment of the subject.
I've been perusing my copy of Gould's 'Structure...' and his argument against the gene view seems to be confused and based on a misunderstanding of the genecentric view. He asked questions of the genecentric view similar to the ones you ask.
how does one predict the fitness of an organism based solely on the activity of a gene or suite of genes?
A fit individual is one which works towards ensuring its alleles replicate.
Is the fitness of an organism in its particular environment dependent solely on genetics, or is fitness a phenotypical characteristic?
No - it is not dependent soley on genetics, as I have been saying for some time. Acquired characteristics can affect fitness. This is why natural selection doesn't select the individual - it only selects that individual's heritable traits (of which there usually many copies of).
Do allele frequencies in a population change over time because of the activities of genes (IOW, is the gene an agent), or because of the phenotypical effects?
No, they change due to the ability of the allele to, on average, work with other genes (and their alleles) well to create individuals that aid in the replication of that allele. Alleles that provide better aid on average will tend to increase in frequency, those that aren't so good will tend to decrease in frequency.
Is it possible (outside of a purely theoretical mathematical construct) to calculate the fitness of an allele without merely abstracting from the measurement of fitness of an individual organism?
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.

This message is a reply to:
 Message 254 by Quetzal, posted 03-24-2007 4:41 PM Quetzal has replied

Replies to this message:
 Message 261 by Quetzal, posted 03-24-2007 7:44 PM Modulous has replied

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


Message 257 of 303 (391361)
03-24-2007 6:44 PM
Reply to: Message 228 by Percy
03-24-2007 9:09 AM


Re: clarification
I'm not going to address your main position directly. The question of whether natural selection is best viewed as individual-centric versus gene-centric is almost like one of those "what's the best text editor" religious wars, i.e., it includes a large element of individual preference.
I don't think a scientific term should be left to individual preference. We need to have a precise understanding of it - even if we gloss over that as an explanatory tool to begin with.
The terms "artificial selection" and "natural selection" have had clear definitions for nearly 150 years
Agreed. However, the meanings of the terms is greater than the sum of their parts. Moreso with natural selection. Pick a card any card - that is selection occurring that is natural. It is not supernatural! However despite it being selection that is natural, it is not natural selection. As you say - that term has its own specific meaning.
There's no argument that man is actually as natural as everything else. That may not be the position you were advocating, I'm having difficulty deciphering your position, and I just mention the "man as natural" position because it's the only interpretation I could come up with. But the important point is that whether that is your meaning or not, or whether some other definition is your meaning or not, it is not the way we traditionally view or talk about artificial and natural selection.
Yes - that man is an animal that is part of the ecosystem, means that its actions can be involved in natural selection (that is man, can cause the increase of or decrease of the frequency of genes of other species (that's nothing special in itself, lions do likewise). Artificial selection refers to specific kind of natural selection. Natural selection artificed by natural agents with foresight.
But the important point is that whether that is your meaning or not, or whether some other definition is your meaning or not, it is not the way we traditionally view or talk about artificial and natural selection
Indeed - most people think that artificial selection is entirely contrastual with natural selection. I do not, and this is the topic to discuss that, neh?
But if you're actually trying to substitute your own preferred definitions for these terms, then I think that is a really, really bad idea.
I didn't invent the concept - and I'm not really substituting. I am simply describing relationships. It is perfectly fine to use aritificial selection to differentiate from natural selection. Since we are being precise here, I put forward the idea that artificial seleciton is a subset of natural selection where the selection pressure is in getting another species (with foresight) to aid in replication. Chickens are the most successful birds on earth because they fill this niche so well.

This message is a reply to:
 Message 228 by Percy, posted 03-24-2007 9:09 AM Percy has replied

Replies to this message:
 Message 262 by Percy, posted 03-24-2007 7:44 PM Modulous has replied

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


Message 258 of 303 (391363)
03-24-2007 7:14 PM
Reply to: Message 255 by Percy
03-24-2007 6:17 PM


Re: Hoot Mon's not entirely unreasonable position:
A simple diagram of Darwin's concepts of natural selection and descent with modification is insufficiently explanatory for you?
No - your diagram was insufficiently explanatory for me.
As you follow the diagram downward and forward in time, natural selection is followed by reproduction (descent with modification).
Natural selection doesn't follow anything, it seems to be labelled as the entire list except death. Consider this: a group of individuals with no genome. They have been built by man. They can make new individuals at random (randomly created individuals are commonly rubbish at making new individuals). Some are quicker at it than others. There is no natural selection here. Each individual that gets created will probably be rubbish, and so will make rubbish new individuals. If a randomly good individual is created, its offspring are probably going to be rubbish anyway.
Here we have differential reproductive success without natural selection.
However, if these individual carried precise instructions with them on how they were built - then we'd see natural selection. Good instructions (that create good and quick individuals) will increase in frequency in the population.
Here we have differential reproductive success that leads to natural selection. If all of these individuals were created with the same instructions there would be no change in the frequency of that set of instructions. There would be no differential reproductive success and there would be no natural selection.
Reproduction, the stage where differential reproductive success occurs, is a consequence of which organisms were selected to reproduce on the basis of fitness.
So individuals who don't get to reproduce are selected out, and become less frequent in the population right?
Social insects are doomed!
...a struggle for survival (natural selection)
A struggle for survival is just survival selection. It differs from, for example, sexual selection.
I'd like to agree with you, I really would, because I feel exactly the same way, but it would be more believable if you weren't taking issue with so many other views of selection
I take no issue with any other form of selection. Many forms of selection are a subset of natural selection. Sexual selection and survival selection are two examples.
You must not have said what you originally set out to say, because you first say that some types of selection have "nothing to do with natural selection,"
That is true. Not all types of selection are natural selection. Picking out an outfit is not natural selection. I have no problem with picking out an outfit (as long as you just get on with it!)
then you critisize the "individualist view" for missing elements of natural selection.
It does. It misses kin selection for example.
It sounded like you were starting out to say that the individualist view misses the types of selection that aren't natural selection.
No the individual selection inadvertantly includes types of selection that aren't natural selection (at least Quetzal's description of the individualist view).
A unified theory of natural selection, huh! I actually agree with you. You've mistaken the simple way I prefer to introduce the concept of natural selection as indicating that I equate natural selection to survival selection. I don't. I already think of natural selection in terms of what you're calling superselection. The nuances of natural selection can be filled in after the basic concept has been successfully communicated, that's the way I'm approaching this.
That's fine - but I feel Hoot Mon understands the basics already - he has done a fine job of discussing the intricacies and the limitations of the individual point of view. Certainly not a perfect job. It is like trying to explain the Bohr model of an atom with somebody who is asking which model is the most accurate and making a good case for why the Bohr model is not the most accurate.
Maybe you are right - and Hoot Mon has dived in at the deep end, but he has done a good job at the deep end and he seems to be doing fine. Trying to convince him to doggy paddle at the shallow end will probably be met with scorn.

This message is a reply to:
 Message 255 by Percy, posted 03-24-2007 6:17 PM Percy has replied

Replies to this message:
 Message 263 by Fosdick, posted 03-24-2007 7:44 PM Modulous has not replied
 Message 266 by Percy, posted 03-24-2007 8:13 PM Modulous has replied

Fosdick 
Suspended Member (Idle past 5500 days)
Posts: 1793
From: Upper Slobovia
Joined: 12-11-2006


Message 259 of 303 (391364)
03-24-2007 7:26 PM
Reply to: Message 253 by Quetzal
03-24-2007 4:08 PM


On proving abstractions
Of course, all you have to do to prove me wrong is present one single study of a real-world, sexually reproducing population that HW actually describes.
Quetzal, would you suppose a “real-world, sexually reproducing population” would ever evolve without something disturbing is established allele frequencies”its HW equilibrium? If that actually happens in nature, and I think it does more than just abstractly, then that population’s HW equilibrium will have been affected in the real-world context.
You know, I suppose one could always argue that Newtonian gravitation is only an abstraction, and maybe the Second Law, too. My point is that models of evolution and its causes will necessarily require some abstraction. Otherwise, we’ll be forced into talking only about the exact moment and location when the amphibians evolved into reptiles, for example, or when the Cambrian exploded.
”HM

This message is a reply to:
 Message 253 by Quetzal, posted 03-24-2007 4:08 PM Quetzal has replied

Replies to this message:
 Message 260 by Chiroptera, posted 03-24-2007 7:34 PM Fosdick has replied
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Chiroptera
Inactive Member


Message 260 of 303 (391368)
03-24-2007 7:34 PM
Reply to: Message 259 by Fosdick
03-24-2007 7:26 PM


Hee hee. Good one.
No, I'm not taking part in this discussion. I just wanna say...
quote:
...when the Cambrian exploded.
I loooove this phrase. I am going to have to use it myself, if you don't mind, Hoot.

This message is a reply to:
 Message 259 by Fosdick, posted 03-24-2007 7:26 PM Fosdick has replied

Replies to this message:
 Message 264 by Fosdick, posted 03-24-2007 7:51 PM Chiroptera has not replied

Quetzal
Member (Idle past 5872 days)
Posts: 3228
Joined: 01-09-2002


Message 261 of 303 (391369)
03-24-2007 7:44 PM
Reply to: Message 256 by Modulous
03-24-2007 6:25 PM


Re: genecentrism revisted
However, I can highlight why one model is inferior to another by showing its weaknesses and how another model does not share those weaknesses.
Okay. Let me know when you're going to do that.
I've been perusing my copy of Gould's 'Structure...' and his argument against the gene view seems to be confused and based on a misunderstanding of the genecentric view. He asked questions of the genecentric view similar to the ones you ask.
Not that I necessarily support Gould, but why would the questions I asked be based on a misunderstanding of genecentrism? These are questions to which phenotpyical selectionists already have an answer, but couched in genecentric language. 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.
Mod writes:
Quetzal writes:
How does one predict the fitness of an organism based solely on the activity of a gene or suite of genes?
A fit individual is one which works towards ensuring its alleles replicate.
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.
This response especially breaks down in the face of behavior - which is Dawkins speciality, btw. Once you get beyond pure genetically programmed behaviors (such as many insects - like your ants - exhibit), the role of genes in behavior gets less and less. As Ehrlich puts it (paraphrasing), "genes don't shout commands, at most they whisper suggestions". To me, your response indicates you feel otherwise. Like I said, you should probably clarify. Do you consider behavior a phenotypical trait that has a fitness implication? If not, why not? If so, how does that square with genecentrism?
Mod writes:
Q writes:
Is the fitness of an organism in its particular environment dependent solely on genetics, or is fitness a phenotypical characteristic?
No - it is not dependent soley on genetics, as I have been saying for some time. Acquired characteristics can affect fitness. This is why natural selection doesn't select the individual - it only selects that individual's heritable traits (of which there usually many copies of).
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.
Mod writes:
Q writes:
Do allele frequencies in a population change over time because of the activities of genes (IOW, is the gene an agent), or because of the phenotypical effects?
No, they change due to the ability of the allele to, on average, work with other genes (and their alleles) well to create individuals that aid in the replication of that allele. Alleles that provide better aid on average will tend to increase in frequency, those that aren't so good will tend to decrease in frequency.
Is the "no" in response to "phenotypical effects" or is the "no" in response to the idea that a gene/allele is an active agent? 'Cause if the latter, you directly contradict yourself in the explanation. "Ability of the allele to...work with other genes" is pretty much the definition of "allele is an agent". Disentangle this for me, will you?
Let's take a look at a real-world example to see how this works, shall we? As everyone knows, sickle-cell is a combination of two different alleles AA and SS. Homozygote AA's and SS's tend to die off before achieving optimal reproduction, although SS's produce far fewer offspring than AA's. AS heterozygotes, although mildly deleterious, do tend to produce many more offspring than either of the others. Thus the fitness of the three goes something like AS > AA > SS. However, these fitnesses result from the phenotypical effects of the combination of these alleles - effects that exist ONLY in organisms. If your interpretation of Dawkins' concept is correct, how, if the gene is not a causal agent in its own right, do these combinations "work together" - and why would they? Help me out, here.
Mod writes:
Q writes:
Is it possible (outside of a purely theoretical mathematical construct) to calculate the fitness of an allele without merely abstracting from the measurement of fitness of an individual organism?
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.
Unless you're trying to say (which I know you're not) that there's a bunch of loose genetic material floating around out in the wild replicating itself, you have not been able to divorce the measurement of a gene's fitness from the measurement of the organism's fitness. Even taking into consideration the contribution of the particular allele to the survival/reproduction of the organism, you still - except in the abstract, as an average over generations - haven't shown that it is possible to discuss gene fitness without recourse to the organism.
"I only touched on the issues..." is right.

This message is a reply to:
 Message 256 by Modulous, posted 03-24-2007 6:25 PM Modulous has replied

Replies to this message:
 Message 267 by JustinC, posted 03-24-2007 8:37 PM Quetzal has replied
 Message 269 by Modulous, posted 03-25-2007 8:23 AM Quetzal has replied

Percy
Member
Posts: 22391
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 262 of 303 (391370)
03-24-2007 7:44 PM
Reply to: Message 257 by Modulous
03-24-2007 6:44 PM


Re: clarification
Modulous writes:
I'm not going to address your main position directly. The question of whether natural selection is best viewed as individual-centric versus gene-centric is almost like one of those "what's the best text editor" religious wars, i.e., it includes a large element of individual preference.
I don't think a scientific term should be left to individual preference. We need to have a precise understanding of it - even if we gloss over that as an explanatory tool to begin with.
We're not leaving definitions to individual preference, but merely the choice of avenue of explication. You seem to be abandoning a point of agreement I thought we reached long ago in this thread, that what natural selection actually is does not change simply because one chooses to describe it from a different perspective.
Agreed. However, the meanings of the terms is greater than the sum of their parts. Moreso with natural selection. Pick a card any card - that is selection occurring that is natural. It is not supernatural! However despite it being selection that is natural, it is not natural selection. As you say - that term has its own specific meaning.
No, that's not as I say, that's as you say. When you describe natural selection I barely recognize it, and the same for artificial selection. I think what may be actually be the case is that you're engaged in a search for definitions that are all inclusive and that can apply in any context, but the world is far too messy a place for that to be possible. The result will be terms far too complex and nuanced for people to ever agree upon a definition, or even understand them.
Indeed - most people think that artificial selection is entirely contrastual with natural selection. I do not, and this is the topic to discuss that, neh?
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.
I didn't invent the concept - and I'm not really substituting. I am simply describing relationships.
If you say so. I'm not really sure what you're doing, but it doesn't look like either clarity or utility to me. For example, you go on to say:
Since we are being precise here, I put forward the idea that artificial seleciton is a subset of natural selection...
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:
Wikipedia on artificial selection writes:
Artificial selection is the intentional breeding of certain traits, or combinations of traits, over others. It was originally defined by Charles Darwin in contrast to the process of natural selection, in which the differential reproduction of organisms with certain traits is attributed to improved survival and reproductive ability in the natural habitat of the organism.
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.
As Quetzal said earlier today (at least I think it was Quetzal), the terms are here, they've already got definitions, and those who find them inconveniently defined may as well get used to them because they're not going away.
--Percy

This message is a reply to:
 Message 257 by Modulous, posted 03-24-2007 6:44 PM Modulous has replied

Replies to this message:
 Message 271 by Modulous, posted 03-25-2007 8:45 AM Percy has replied
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Fosdick 
Suspended Member (Idle past 5500 days)
Posts: 1793
From: Upper Slobovia
Joined: 12-11-2006


Message 263 of 303 (391371)
03-24-2007 7:44 PM
Reply to: Message 258 by Modulous
03-24-2007 7:14 PM


Re: Hoot Mon's not entirely unreasonable position:
Maybe you are right - and Hoot Mon has dived in at the deep end, but he has done a good job at the deep end and he seems to be doing fine. Trying to convince him to doggy paddle at the shallow end will probably be met with scorn.
Thank you, Modulous. That was a very well-reasoned post (even though I can find quibbles). It makes me realize even more that the gene's-eye view of evolution is important in understanding what natural selection is and how evolution works. It helps a biologist take a more rigorous look at what Darwin was unable to see.
”HM

This message is a reply to:
 Message 258 by Modulous, posted 03-24-2007 7:14 PM Modulous has not replied

Fosdick 
Suspended Member (Idle past 5500 days)
Posts: 1793
From: Upper Slobovia
Joined: 12-11-2006


Message 264 of 303 (391375)
03-24-2007 7:51 PM
Reply to: Message 260 by Chiroptera
03-24-2007 7:34 PM


Re: Hee hee. Good one.
quote:
...when the Cambrian exploded.
I loooove this phrase. I am going to have to use it myself, if you don't mind, Hoot.
Please do. I don't use smiley faces, but my hoot owl is winking.
”HM

This message is a reply to:
 Message 260 by Chiroptera, posted 03-24-2007 7:34 PM Chiroptera has not replied

Quetzal
Member (Idle past 5872 days)
Posts: 3228
Joined: 01-09-2002


Message 265 of 303 (391380)
03-24-2007 8:10 PM
Reply to: Message 259 by Fosdick
03-24-2007 7:26 PM


Re: On proving abstractions
Quetzal, would you suppose a “real-world, sexually reproducing population” would ever evolve without something disturbing is established allele frequencies”its HW equilibrium? If that actually happens in nature, and I think it does more than just abstractly, then that population’s HW equilibrium will have been affected in the real-world context.
No, I'm saying that no real world population has EVER exhibited anything resembling HW equilibrium in the wild. That HW isn't even intended to describe the real world. If you believe otherwise, then show me the study.
Now back to your originally scheduled topic.

This message is a reply to:
 Message 259 by Fosdick, posted 03-24-2007 7:26 PM Fosdick has not replied

Percy
Member
Posts: 22391
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 266 of 303 (391381)
03-24-2007 8:13 PM
Reply to: Message 258 by Modulous
03-24-2007 7:14 PM


Re: Hoot Mon's not entirely unreasonable position:
Modulous writes:
Percy writes:
As you follow the diagram downward and forward in time, natural selection is followed by reproduction (descent with modification).
Natural selection doesn't follow anything, it seems to be labelled as the entire list except death.
I apologize for having to use character graphics, but that's what's available. I didn't really think it was that bad, came out pretty clearly on my display. Anyway, you've missed key parts of the diagram. Here it is again:
[face=courier new]                                             _
sperm/egg conjoinment                         |
fetal development                             |
birth                                         |
growth to adulthood   _                       |--Natural selection
finding a mate         |                      |
mating                _|--sexual selection   _|
gamete combining                              |
possible pregnancy period                    _|--Reproduction (Descent
death                                            with modification)
[/face]
Natural selection extends from "sperm/egg conjoinment" only as far as "mating". Below natural selection and afterward in time is reproduction or descent with modification, encompassing "gamete combining" and "possible pregnancy period." Natural selection is not "the entire list except death."
I composed this diagram to illustrate how you have it backwards with respect to the order of natural selection and differential reproductive success.
You go on to point out exceptions, but of course there are exceptions. The idea of the diagram wasn't to explain all of evolution, but just to illustrate the order of natural selection and descent with modification. Once these concepts are clear then you can begin composing variations to broaden and nuance the basic concept to show how it can encompass all of nature from soldier ants to asteroid strikes. But overburdening the definition of natural selection to accommodate the entire universe of evolutionary possibilities is not a good idea. Reality is what it is, and it's pretty messy a lot of the time, and oftentimes you're going to have processes that don't have a single term that describes them, and that's when you use entire sentences and paragraphs that take advantage of the glossary of biological terms and the whole rest of the English language.
Maybe you are right - and Hoot Mon has dived in at the deep end, but he has done a good job at the deep end and he seems to be doing fine. Trying to convince him to doggy paddle at the shallow end will probably be met with scorn.
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.
--Percy

This message is a reply to:
 Message 258 by Modulous, posted 03-24-2007 7:14 PM Modulous has replied

Replies to this message:
 Message 268 by Fosdick, posted 03-24-2007 8:45 PM Percy has replied
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JustinC
Member (Idle past 4843 days)
Posts: 624
From: Pittsburgh, PA, USA
Joined: 07-21-2003


Message 267 of 303 (391384)
03-24-2007 8:37 PM
Reply to: Message 261 by Quetzal
03-24-2007 7:44 PM


Re: genecentrism revisted
quote:
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 would just like to point out that meaning and usefulness of the term "fitness" is disputed in the literature. The idea is that there is a quantity called "fitness" which increases throughout time due to natural selection.
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. Think about how hybridization can increase the number fertile offspring but that further reproduction will result in sterility of the grandchildren.
So it can't just be the fecundity in one generation. The best way to get around this is to define it as "the number of descendents alive in the distant future." But, as Dawkins points out in The Ancestors Tale, 80 percent of those alive today will be an ancestor of the entire population in the distant future so they'll have maximal fitness. This seems absurd. Then, in addition to that absurdity, you'll contribute very little hereditary wise to those descendents since you're contribution will dwindle to near zero as your genes are passed through each generation.
"Fitness" may be a good hueristic for understanding NS, but I'm not too sure it has a good foundation when looked at deeply.
Of course, I could be wrong but that's my take (my take basically being derived straight Dawkins).

This message is a reply to:
 Message 261 by Quetzal, posted 03-24-2007 7:44 PM Quetzal has replied

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Fosdick 
Suspended Member (Idle past 5500 days)
Posts: 1793
From: Upper Slobovia
Joined: 12-11-2006


Message 268 of 303 (391388)
03-24-2007 8:45 PM
Reply to: Message 266 by Percy
03-24-2007 8:13 PM


Re: Hoot Mon's not entirely unreasonable position:
Natural selection extends from "sperm/egg conjoinment" only as far as "mating". Below natural selection and afterward in time is reproduction or descent with modification, encompassing "gamete combining" and "possible pregnancy period." Natural selection is not "the entire list except death."
No. It's much simpler than that. Natural selection is, by agreed-upon definition, the differential reproductive success amongst individuals of a population. That's all.
”HM

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 270 by Percy, posted 03-25-2007 8:37 AM Fosdick has not replied

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


Message 269 of 303 (391474)
03-25-2007 8:23 AM
Reply to: Message 261 by Quetzal
03-24-2007 7:44 PM


Re: genecentrism revisted
Okay. Let me know when you're going to do that.
Clever come back. I 'get' that you don't think I have done this. I am still waiting for a decent individualist account of social insect selection.
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.
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.
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.
To me, your response indicates you feel otherwise. Like I said, you should probably clarify. 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.
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).
Is the "no" in response to "phenotypical effects" or is the "no" in response to the idea that a gene/allele is an active agent?
Essentially to both - since neither captured the essence. I then provided a more accurate accounting of how allele frequencies change in the genecentric view. Yes - the gene can be viewed as an agent (or rather, the sum total of all the genes and their alleles), but I thought I'd give you a more complete understanding of my position since it is a little more involved than all that - it involves tendencies and the like.
However, these fitnesses result from the phenotypical effects of the combination of these alleles - effects that exist ONLY in organisms. If your interpretation of Dawkins' concept is correct, how, if the gene is not a causal agent in its own right, do these combinations "work together" - and why would they?
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.
Unless you're trying to say (which I know you're not) that there's a bunch of loose genetic material floating around out in the wild replicating itself, 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.
Edited by Modulous, : No reason given.

This message is a reply to:
 Message 261 by Quetzal, posted 03-24-2007 7:44 PM Quetzal has replied

Replies to this message:
 Message 278 by Quetzal, posted 03-25-2007 12:06 PM Modulous has replied

Percy
Member
Posts: 22391
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 270 of 303 (391477)
03-25-2007 8:37 AM
Reply to: Message 268 by Fosdick
03-24-2007 8:45 PM


Re: Hoot Mon's not entirely unreasonable position:
Hi Hoot Mon,
Well, looking at the "Upcoming Birthdays" list, it looks like I have to go off and track down a bug, but fortunately this type of response can be addressed briefly:
No. It's much simpler than that. Natural selection is, by agreed-upon definition, the differential reproductive success amongst individuals of a population. That's all.
This is just a restatement of your position, which itself is just a misunderstanding of the definition of natural selection. We already know what you believe. You need to identify the weaknesses in my argument and explain why you take issue with them. It's called rebuttal.
Debate has to take the form of addressing each other's arguments, otherwise it devolves into "Is-not, is-too".
--Percy

This message is a reply to:
 Message 268 by Fosdick, posted 03-24-2007 8:45 PM Fosdick has not replied

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