What exactly is natural selection and precisely where does it occur?

Yet they do experience selection. The longer ones are less likely to be present in the gene pool with each passing reproductive event. Eminence speaks of qualification to discuss the topic with expertise. My mistake. I did not mean to be ambiguous. I did not mean to ask why did the individuals get selected, I meant to ask what they are getting selected for? For what result. For example, if I have a collection of stones and you picked the biggest one - the reason you selected it could be that you wanted to weigh something down or use it as a weapon.I say genes get selected to make more copies of themselves.What do individuals get selected to do? I assume you'd say 'reproduce'. Which is another way of saying 'making copies of their genes'. Can you not see how it can be viewed as the genes have been selected to make copies of themselves. Those genes that make successful phenotypes, get passed on more than those that don't. And that is the heart of natural selection in my opinion.I can certainly understand why someone might disagree - but hopefully you can at least understand the opposing viewpoint? I Super Mutant X tends to only come alongside the gene progeria, then the Super Mutant X gene will be selected out of the gene pool. The sufferer is not part of the gene pool - they aren't genes - they get selected out of the population, but so does everybody so that isn't very interesting. However, if it helps others reproduce then it will be selected for and its frequency in the gene pool will increase. Right - and through this mechanism weak genes will be selected against, and the stronger ones will be selected for. Sure, some strong genes are lost in those phenotypes - but there are hopefully plenty of copies still in existence. We'd expect the proportion of good genes to go up in the population compared with the bad ones. There is a positive selective pressure on the good ones, and a negative pressure on the bad ones.

I think the viewpoint that "Natural selection operates upon gangs of mutually compatible genes" is an interesting perspective, but Darwin didn't need genes to define natural selection, I don't myself find it a helpful perspective, I don't think it's found much acceptance as a way of defining natural selection, I think it is a less accurate characterization of what is actually happening, I think it makes it more difficult to explain natural selection to Hoot Mon, and I don't think Dawkin's selfish gene concept has been as influential within scientific circles as you seem to believe.--Percy

Impossible! Only the genes for those phenotypes get passed on homologically. Ears and noses, for example, are not contained in the gametes, only the genes and alleles for them get to go on that ride. And it is only on that ride where NS does its work.”HM

quote:

---

quote:

---

An organism is only as "evolutionarily strong" as it's "weakest" gene, regardless of how great other genes might be - since an organism either passes on half or more of it's genes, or none at all.

---

​

Right - and through this mechanism weak genes will be selected against, and the stronger ones will be selected for. Sure, some strong genes are lost in those phenotypes - but there are hopefully plenty of copies still in existence. We'd expect the proportion of good genes to go up in the population compared with the bad ones. There is a positive selective pressure on the good ones, and a negative pressure on the bad ones.

---

One thing that is easy to miss here (simply because we are humans who didn’t evolve to deal with massive parallel experiments), is the fact that even a small advantage can cause a single gene to increase in frequency, despite random factors and it’s being always included in an aggregate of alleles.Now, that was hard to understand. Let me explain. As a scientist, I often do large “design optimized experiments”, where many variables (say, 8) are run in many (say, 160 of them) experiments. Then the data from all those experiments is statistically calculated to see if any of the variables shows an effect on the outcome. If even a small effect is present, it often shows up in this process (called “linear regression”).So what does that have to do with alleles? It means that if a gene is present in hundreds of individuals (which it will be within a few generations, unless it is very strongly selected against), then it can slightly affect the reproductive success wherever it appears. If this effect is very small - say just a 5% chance of producing one more offspring than an individual lacking the gene, then it still has an effect over those hundreds of cases. Now, multiply that effect by hundreds of more generations, each with hundreds of individuals, and it becomes a huge effect, just as lightly pushing an asteroid will eventually radically change it’s orbit.It’s easy for us, as humans looking at a few individuals in a few generations, to forget this. This shows why the fact that alleles are always in groups of alleles isn’t really that important, and why it can be misleading to focus too much on the fact that an organism is only as strong as it’s weakest allele.Have a great day everyone-

Clearly they don't experience natural selection; you might say that they experience a sort of "gene selection." None of those figures are involved in this discussion, I notice, so I don't see the relevance of "eminence". I don't see how that question could be relevant without ascribing a telological purpose to evolution and selection.Things get selected for the reasons Darwin originally said - because a given population of organisms will, eventually, grow so large that their environment cannot sustain all of them; at that point, some organisms will reproduce and some will not. Some organisms will reproduce more and some will reproduce less. Statistically, which individuals do or don't will be affected by their adaptations to their environment.But to ascribe agency to genes, as you appear to be doing, is a fantasy. It's a metaphor gone too far; I notice people have a tendancy to do that to Dawkins' material. Often it's just "not die right now." Or, we might call it "making another individual." See, we can reword whatever we want to make either genes or individuals the focus of selection. How you get gene-focused selection out of that is still a mystery to me.

(better structure will occurr in response to AZPaul as I will be following Gould not myself thereat)If that

quote:

---

Hamilton, Dawkins, et al. have argued that genes can be quite strategic in their adaptations for survival, even to the extent of demonstrating altruistic determinsim. So, individual survival may NOT be the real focus of natural selection;

---

is the case then YOUR MODEL possess tons of teleology that needs to be explained away where there adaptive fit is no longer tolerated. If “the genes” (“their adaptations”) have the property of ”being adapted’ in the design of any determinism you claim to name then what is the specific biophysics (chemical bond forces etc and where to directed . ) within the ”copy’ and that without it. As soon as there is an external/outside space/place of the adaptation, certainly some entities are more fit and have less tolerance than others . there is an aspect/property of said gene that no matter the strategy or altruism projected within (like in geometry where one determines an angle and triangle etc) by NOT within and THIS is teleological and goal directed if the selection is made artifical with respect to the individual no matter the actual copy number, as would occur in the small, nanotechnically in the future etc, should such be.This view is myopic.If it is not a shortcut then show me some diagram/design which displays in all the Dawkins’ engineering rigor what forces create what GENEadaptation and to what geometrical space is the dimension of this??I do not come from the perspective that alternatives to Dawkins’ view needs to be explained but that Dawkins’ view IS THE atlternative, that is how it read simply and completely to me the very first time I read his work etc. and RD thus needs to carry the burden of proof not the passed on and taught thought of evolution itself. That is why I made a short cut through international takes on the topic.In Post 55 you had

quote:

---

Since no individual survives long enough to actually experience NS, then the operational site of NS must be somewhere or something else.

---

but this statement or sentence shows less filiation to the heritage of statistics in biology (large or small population) then it does to value in the place of a world of facts. There is *some* number of events actually but one can know what 2/3 or something is before one has a reliable estimate of actual quantity.This kind or reasoning may have effected me in the early days of posting on EvC but as nanotechnology developed an emboldened confidence in the past few years it became clear to me that given something like Wolfram’s ideas applied it would, on those ideas, be possible to alter the praxis that NS traditionally denotes. Dawkins can only tilt this windmill to the future. I need simple sit back on my haunch and hunches/lunch.I have NO interest in evolution if it is not about individuals. The world would sooner die of religious warfare than that reality exist, it seems to me. The problem is my horizon already formed, functionalism can not alter it.Sayins such as Moduluous’(post 63)

quote:

---

No individual will survive. The only thing that survives are the genes (until universal extinction of course).

---

overdetermines THE FORM.It is precisely with issues of form that creationism can be put to bed so IF it is evc then evos should not try to have their cake so that they can eat something else instead.What is going on here is that one goes beyond the notion of science to one of operationalism or practicalism but this is really an aspect of technology not biology say sensu stricto. It occurs from a particular philosophy about probabilisms but assumes rather than historicizes the contingency between environment and organism. There IS ALWAYS an external to this view.So now all we can have is the “math” of the ”unit’ , let it come forth.The problem reared it’s sleepy head when Mod wrote

quote:

---

Yes - but not all phenotypical characteristics are hereditry.

---

in post 71. As long a this can be formally imagined there is some position beyond the genes involved but from a nexus of form this only need be conceptualized rather than algorithmized as would be incumbent on those doing the book keeping.It can never be said that a biologist can not use non-adaptive charcters to become adaptive in AN EVOLUTIONARY THEORY of tommarrow, but because there is not as intricate a community of pure and pratical biologists as there are physicists biology lacks the momentum in this regard that physics HAS, so, the debate force of Mod position is weakened and ineffectual for debate even though it may not alter one side or the other’s privately.Again if the gene eyepoint of view is true, then what are the biophysics of genes’ adaptations for programmed cell death for instance? Functional notions of copy number, “cooperation” and assorted functionalism need to be explained not sequentially but form by form. Who can do this? Did Hamilton??

Mod - I understand Dawkins' concept. I have also said that a "genes-eye-view" of evolution is both useful and, over the long term, makes sense. I thoroughly "get" the idea that we can look at evolution in terms of the success of genes to get themselves passed down the generations. On the other hand, we're not talking here about evolution per se, we're talking about natural selection - those factors that influence whether or not those "optimal" genes get transmittted. In that case, I submit that selection doesn't operate on genes, it operates on individual organisms, during their very own lifetimes. Although some selection pressures will operate over generations (it's how adaptation occurs in the first place, as you know), for the purposes of understanding those selection pressures we lump under the rubric of natural selection, the only thing that makes sense is to look at the effects of those factors on the individual organism. After all, it's the organism as a whole - good, bad, and indifferent genes - that has to survive to reproduce. It's not really a question of "sides". It's really more a question of looking at the facts in a different way. Both "sides" have their uses. Population geneticists would probably agree with Dawkins. On the other hand, I don't find this view particularly useful for understanding ecosystem-level interactions, especially extinctions - one of my particular concerns. Nor is it particularly useful for any other aspect of conservation biology or ecology that I can think of. Perhaps, as I mentioned, it's a question of personal biases and experiences. All I see it as is a nice sort of theoretical way of looking at the question. Right, I understand that. Again, however, you're not talking about natural selection as such, you're talking about evolution. Since the topic is "at what 'level' does natural selection operate, I think that the genes-eye-view is inappropriate. Perhaps I'm making a false distinction: evolution vs. one of the key mechanisms of evolution.

Modulous is doing a good job of explaining what I already agree with”NS works on genes and the frequencies of their alleles.Percy, Dawkins has had an enormous impact on evolutionary biology. A literary war was waged over the selfish gene theory between Oxford and Harvard. And Harvard had its own intenal wars over it”E. O. Wilson sided with Dawkins. Even S. J. Gould eventually agreed, mostly, with Dawkins. Earlier, in the 1970s, Wilson and Hamilton nearly started a riot on the campus of U of Mich over their emphasis on genes in the teaching of "sociobiology."”HM

quote:

---

Percy, Dawkins has had an enormous impact on evolutionary biology.

---

By the way, what has Dawkins done in biology? I mean, I know that he is a trained biology, but what was (or is) is field of research?And what impact has Dawkins had on evolutionary biology?All I know about Dawkins is a couple of books he wrote for the mass public. In fact, he is currently the Simonyi Professor for the Public Understanding of Science at Oxford, which sounds like it is more of an educational post than a scientific research one.

---

Actually, if their god makes better pancakes, I'm totally switching sides. -- Charley the Australopithecine

Quetzal, how so? Are you saying that Arnold Swartzenager, as one example of an individual organism, could have experienced natural selection?”HM

Yeah, and what has Stephen Hawking done for science, slouching there in Newton's chair?”HM

Well, if you don't know the answers to the questions, Hoot, why don't you take a break and let someone else answer them?

---

Actually, if their god makes better pancakes, I'm totally switching sides. -- Charley the Australopithecine

As Quetzal makes clear in Message 82, we all understand both Darwin's and Dawkins' perspective, it's just that we happen to prefer Darwin's for defining natural selection while Modulous prefers Dawkins'. If you prefer Dawkins perspective then I think that's fine, but what you've written so far in this thread leads me to suspect that you don't understand either one. The Darwin and Dawkins perspectives are only minimally in opposition to one another. In many ways they're saying the same thing. After all, what is a "gang of mutually compatible genes" but an individual!Quetzal, Chrioptera, Crashfrog and myself are not saying that the selfish gene perspective is erroneous, not at all. We're only saying that it isn't the most helpful perspective for defining natural selection, it isn't the way natural selection was originally defined, it isn't defined that way in popularizations, it isn't defined that way in textbooks, and it isn't the way most scientists would define it today. As with memes, Dawkins has influenced a generation of laypeople to a point of view that holds little sway in scientific circles, much like Stephen Gould and punctuated equilibria, which has had a far greater influence in forums like this than in scientific research.I think even E. O. Wilson agrees that the selfish gene perspective is not an effective one for defining natural selection, which he explains like this in the introduction to his book of Darwin's collected works: As much as E. O. Wilson might accept the selfish gene perspective, he doesn't seem to think it a very effective approach to explaining natural selection. You can prefer the Dawkins' perspective if you wish, as does Modulous, but Modulous understands the Darwin perspective and realizes it isn't in significant opposition to Dawkins.--Percy

quote:

---

On the other hand, we're not talking here about evolution per se, we're talking about natural selection - those factors that influence whether or not those "optimal" genes get transmittted.

---

How are you defining optimal here? Since, as you say, natural selection acts on the individual, that is the sum of the effects of the genotype on the phenotype, wouldn't "optimal" simply be defined in relation to the other genes, i.e., a gene is optimal if it is incorperated in the most number of successful genotypes.In this sense, even though it is the sum of the effects that gets selected, a gene that is incorperated in the most number of successful sum of effects (inelegant, i know) will tend to proliferate in future generations. The gene has differental reproductive success by way of being incorperated in the most successful genotypes, and by extension, the phenotype. So the factor that's most important to the reproductive success of the gene is how well it interacts with the rest of the genotype, even though this interaction may be by way of circuitous route of the phenotype.

When we break down "differential reproductive success," we realize that it implies "reproduction" or "to reproduce." With sexual organisms, the word may be somewhat of a misnomer if we are referring to the individual, i.e., is the individual reproducing itself?The word reproduce implies that the reproduced copy be produced with some high degree of fidelity. For a silly example, if I draw a picture of myself it would not be an example of an act of reproduction since the differences between me and a picture of me are significant. In a simlilar sense, to say that a child is an example of a reproduction of an adult makes little sense except in asexual organisms.So what is being reproduced differentially? The genes. Why? Because of the traits they produce.Natural Selection-the differential reproductive success of genes due to the traits they produce.Also, even though Darwin didn't have a concept of a gene doesn't mean that NS isn't more accurately defined in terms of them. Darwin talked about traits increasing in frequency throughout the generations, we recognize these traits have genetic origins. Edited by JustinC, : clarification