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

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Since whatever is being selected must be somethng that can be inherited and must be something that we can find in many individuals, it makes more sense to look at genes. The view of a single gene working in isolation is certainly oversimplified but - for sexually producing organisms - it comes closer to what is actually going on.

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Does the distinction "selected for" and "selected of" help the situation? That is, there is selection of genotypes for for phenotypes. And the genes that can work well with the most assortments of genes get selected (the genes that are incorperated in the most number of successful genotypes), but their success is rooted in the sum of the effects of the entire genotype on the phenotype, that is the individual.I'm not sure if I said anything opposed to your position or not; i'm thoroughly confused wrt to "the unit of selection".

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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.

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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

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So I'm not sure it makes any sense at all to try to define the focus of natural selection based on the behavior of sexual organisms; such organisms are little more than a corner case in the grand scheme of things.

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I didn't think I was saying that. I meant to get across that "reproduction" makes more sense in asexual individuals than sexual individuals.Of course, the meanings of words change so I'm not trying to say one connatation is wrong. But with regard to "differential reproductive success" I think the form of reproduction that is being implied is the asexual kind, i.e., produced again with a high degree of fidelity.This type of "reproduction" applies to genes, haplotypes, etc. and the entire genotypes when talking about asexually reproducing organisms. Edited by JustinC, : typos

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This sounds more like the differential reproductive success that results from natural selection.

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I know you said you are trying to avoid quibbles with others, but can you unpack this statement a little? It doesn't really seem to make sense, from my perspective.Natural selection is a type of differential reproductive success that results from heritable properties of a particular unit (unit being the focus of this debate).When you say differential reproductive success results from NS, it sounds like you are implying that NS happens first and this, then, causes differential reproductive sucess. This doesn't seem quite right, though we could be using words differently.The only way I could see that making sense is if by NS you meant fitness, that is:

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We could even combine our two definitions and arrive at, "Natural selection operates on individuals, and their different fitnesses result in differential reproductive success."

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Two cheers for this definition (only two because I think the concept "fitness" can be confusing and needs to be thoroughly qualified, i.e, never introduce NS as "survival of the fittest")[edit] After reading Quetzel's quote, I believe I can understand your position better. The quote being I didn't realize some biologists made the distinction between selection and the change in frequency of traits in the population that results from it. Edited by JustinC, : No reason given.

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7. Hoot Mon, do you believe sexual selection can occur without natural selection occurring? (Answer: Yes.)

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This I don't understand. It is very easy to see that sexual selection is a type of natural selection from the gene-centric viewpoint.I'm not going to distinguish between NS and differential reproductive success because that makes most sense in individualist-thinking. So i'll define natural selection as I have before If you basically agree with above definition, then its clear that the genes of the sex competing for attention will have differential reproductive success due to the traits they produce (e.g. peacock tails, bird songs, etc.)On the other side, the genes of the sex that is being discriminatory about their mates will have reproductive success due to their discriminatory phenotype, i.e., they'll "choose" genes from other individuals that they'll interact with most optimally, or something to that effect.

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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.

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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).