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

Percy, Quetzal, Chiroptera, et al, I think I understand your problem with the specific meaning of natural selection. You think natural selection is anything that affects the survivability and general wellbeing of individuals or genes in a population, while not necessarily affecting the evenness of reproductive success amongst its individuals. If, for example, a mutation occurs that affects certain individuals by making them shorter, then that, in and of itself, by your reasoning, would be a form of natural selection”nevermind if it helps or hurts their reproductive success. But it's good to remember that natural selection it is not the only mechanism of evolution.Let me point out, as I did earlier, the five known causes, drivers, or mechanisms of evolution:1. Random genetic drift”change in allele frequencies owing to decrease in population size (non-selective)2. Gene flow”genes/alleles entering or leaving a gene pool (non-selective)3. Mutation”heritable nucleotide sequence alteration (non-selective)4. Sexual selection”differential mating success (non-selective)5. Natural selection”differential reproductive success (selective)Evolution can happen without natural selection. There are four other “drivers.” Sure, any one or more of them may affect the evenness of reproductive success in a population (i.e., natural selection), but any one or more of these mechanisms may bypass natural selection altogether en route to an evolutionary event.You seem to be saying, if I understand you correctly, that natural selection is all five of the above, whether or not they cause differential reproductive success in a population. You might be saying that mutation, for example, serves the cause of natural selection. I would not necessarily agree, because evolution can happen apart from natural selection. Random genetic drift is as valid a mechanism of evolution as natural selection is.”HM

I don't understand how you're back to the same mistake as before. Clearly a process called "sexual selection" is not best described as non-selective?If sexual selection is non-selective, then how does it result in traits like the bright feather displays of male peacocks or the curling, protective horns of rams?

Mutational events are not "a form of natural selection." No one is saying anything remotely like this, probably because it's wrong.When you're having trouble with a concept, often the best approach is to find a simple example. The simplest I can think of is a breeding experiment. Breeders carry out artificial selection, not natural selection, but the exact same principles apply, which is why Darwin used artificial selection as preparatory material to natural selection in Origins.A breeder of Burmese cats wants to create a sub-breed that is pure white. He selects the most white male and the most white female and breeds them together. That is selection, artificial in this case. The selected pair will produce offspring. Those not selected will not produce offspring. But the production of offspring is not part of the selection process. The production of offspring is the "descent with modification" part of evolution.There are other ways of looking at natural selection that are equally valid, but until you grasp this simplest of perspectives on natural selection you're just not going to grasp the concept itself.--Percy

Sexual selection, in and of itself, is not the same kind of selection referred to as "natural selection. In the conext of Darwinian evolution, natural selection occurs only when there is differential reproductive success in a population. If something drastic happens to a population, such as bottlenecking, that population can evolve without any change in the distribution of reproductive success amongst its individuals. In that case, drift alone accounts for whatever evolution occurs, and natural selection doesn't.”HM

This is a pedestrian view of Darwinian evolution. You haven't addressed my rigorous breakdown of its causes. You only put simplistic concepts on the table. This thread is about definining exactly what natural selection is and precisely where it ocuurs. In your Burmese-cat-breeding example you attribute artificial selection to a human breeder. What is the equivalent of a human breeder in natural selection? Mother Nature? God?”HM

That was my point. My point was that natural selection is not selection that is natural any more than artificial selection is selection that is artificial. The phrases mean more than the sum of their words.Quetzal said: I was saying that just because random selection occurs, we should not necessarily call this selection natural selection. These random perturbations are not natural selection. Whilst evolution would occur if this kind of random selection where the only thing at play - it would not be natural selection. Quetzal seemed to be saying that characteristics that are not hereditry (such as 'bad luck' injury) can be selected for and that this is also natural selection. He was claiming that genecentric view ignores this kind of selection. I attempted to show that this was not the case by arguing this kind of selection is not natural selection. Darwin specifically said: Darwin did not know about the fundamental unit of heredity. The smallest unit he could talk about was 'trait'. Traits are what get selected for in Darwin's gene-ignorant world. Not individuals. Darwin, for the most part, rejected Lamarckism - not all traits are hereditry. It is those traits that are hereditry that are subject to selection. We know that traits that are hereditry are hereditry because genes work together to create those traits. Those genes ability to work together are the subject of selection - even in Darwin's view. Natural selection acts on the variations to improve individuals' fitness. I am not denying that Darwin, even in that same chapter, discussed the selection of individuals. It is the easiest way to illustrate natural selection after all, and I am not trying to say that Darwin's view is the be all and end all. Indeed, I think Darwin's views were often simple compared with today - and I'd hope anyone else would agree. The point I'm making is that even Darwin, even if unconsciously, came upon the controversy of individual vs 'trait' selection. To demonstrate Darwin's shifting of the subject of selection: I consider the viewpoint that it is the characteristics of swiftness and slimness that are being selected is a better and more accurate way of explaining what is going on - though perhaps less easy to explain. Again - that is my point precisely. There are more than one type of selection. Natural selection should be confined to being the kind of selection that introduces a non-chance element to the process of evolution. In this, natural selection should not be a confusing term - but sometimes it has to be pointed out that just because a selection has taken place does not mean that natural selection has occurred. To be honest, I think Hoot Mon is being more cogent than many are giving him credit for. There might be some issues of understanding going on, but I think it is happening both ways. That is why I stepped in - to try and explain the position Hoot Mon was trying to, but which some people seemed to be needlessly disparaging - perhaps because they didn't understand what Hoot Mon was trying to say. Since I thought I did, I thought I'd try explaining it myself to see if it helped.

Hoot gets to the difference of 4) AND 5) VIA the 2nd which provides an induction that may not exist. Panbiogeographers would add that purely spatial factors need to be considered.Yeah, he went back. His reply in 184 did not "flow" for me.If the list was made in terms of atoms rather than genes he might have something. I cant see it.Edited by Brad McFall, : wrong negation

Then clearly sexual selection is a kind of natural selection, because sexual selection causes differential reproductive success.It takes two to tango, as you may be aware. If females prefer to mate with, or are even exclusive to, males that have prominent displays or males who win intrasexual combats, then differential reproductive success is created - males who have those displays or can win those combats reproduce more; males with no such displays or who are the losers of such combats experience less reproductive success, or perhaps no success at all.Clearly female mate choice represents a selective force. It's not clear to me how this can be denied after so many examples. I'm not sure what any of that has to do with sexual selection. Sexual selection is not genetic drift; it's natural selection. There's nothing non-Darwinian about sexual selection; indeed, it was Darwin who came up with the concept.

Can geneic selection act on putative non-adaptive traits such as minor scale variation in snake skins that do seem to be clined with evironmental temperature regimes in some cases?Some research indicates that it is the lipids and not the keratin that provides the difference in lack of water loss for reptiles (compared to amphibians).Could reptiles have evolved from amphibians by "bad luck" where lipids released on injury somehow metabolically affected the chiken and egg future reptile skin keratinization thus sealing the case and creature?If reptiles DID so evolve would this not be natural selection in the wild as per:If one can think of the phenotype linguistically as not otherwise configured than squash shapes fully it must be obeyed that as:Wright completed his four volumes entitled:1) Genetics and Biometric Foundations
2) Theory of Gene Frequencies
3) Experimental Results and Evolutionary Deductions
4) Variability Within And Among Natural PopulationsIn 1978

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And by 1986
John Endler
People | Ecology, Evolution and Marine Biology | UC Santa Barbara
wrote:Natural Selection in the WildBut today Will Provine and others are downplaying “Wright’s causation” BUT THEY THINK THIS WITHOUT WORKING OUT A DIFFERENT ”deduction’ for natural and artifical selections. I know Will does not use the deductive mathematical process and thus there is little work being done which uses the ENTIRE THOUGHT PROCESS of the four volumes.The confusion in this thread seems to be due to attempts by the elite to elide Wright’s “deduction” among “natural populations” but keep a selection with Endler artifically. This is the kind of move that creationists rightly gasp at. It is like what happened when creationists were told that paleontologists were no longer arguing for transitions anagenically but were predicting gaps.Wright had done a lot of work on domestic breeding programs and the rearing of lab animals but his work was to show how the extension to selection in nature occurs.Unless this work is attended to, in, its purely mathematical, as well a physiological genetics aspects, artificial and natural selection will become MORE fused than unconfused as they were originally for Darwin.To do otherwise attempts to possibly put genes in two places at the same time.“Pick a card” any card only becomes an inaccessible cardinal of thought if the deduction is obviated. The move to have this be the default background is groundless. Thus the scenario of the creeping things above.Edited by Brad McFall, : BBEdited by Brad McFall, : repeated text removed

You're talking about the guy who says that sexual selection is non-selective. You know that, right?Am I the only one who sees those posts, or what?

If you say so. But if you do then would you please file for a redefinition of natural selection. My definition of natural selection pretty well agrees with E. O. Wilson's definition (from Sociobiology, 2000, p. 589):

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Natural selection. The differential contribution of offspring to the next generation by individuals of different genetic types but belonging to the same population.

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Sexual selection may or may not affect "the differential contribution of offspring to the next generation." What I am saying, again, is that sexual selection is a different kind of selection that does not qualify as natural selection. Yes, natural selection could possibly result from sexual selection, but it doesn't have to in order for it to be an agency of evolution. Again, sexual selection is NOT the same thing as natural selection; it is considered by evolutionary biologists as a "non-selective" agency of evolution, meaning 'not a form of natural selection'.”HM

I don't see that there's a need to do that. Sexual selection is clearly consistent with natural selection in every accepted way to formulate it. Obviously it does; if you're a male with no bright plumage, for instance, and no female chooses you for mating, then clearly your contribution of offspring to the next generation is zero, which would be different than the males with bright plumage who were selected for and were allowed to mate. It's not clear to me how many different examples I have to use to inform you that you are wrong about that. Completely wrong. Sexual selection is a form of natural selection, a fact understood by Darwin and every subsequent biologist. There is no one who considers it this way besides you. Sexual selection is recognized by every biologist as a form of natural selection, being that it is a selective influence on the gene pool and results in differential reproductive success, per definitions you yourself have supplied. What's the mental block that's preventing you from seeing this?

Like who? It clearly isn't non-selective and it fits E.O Wilsons definition perfectly. A genetic trait which is favoured by sexual-selection will lead to its possessors contributing more offspring to the next generation by virtue of a better chance of mating.What you really seem to be trying to say is that 'mate choice' is not necessarily natural selection, but 'mate choice' is also not necessarily the same as sexual selection.TTFN,WK

Why does sexual selection necessarily have to affect the evenness of reproductive success amongst individuals of a population? Sexual selection, in and of itself, could cause an evolutionary event without disturbing the eveness of reproductive success amongst individuals, which would mean in that case that there was NO natural selection.”HM

Bear this in mind, frog. You needn't bother over the word "selection" in sexual selection. Sexual selection may also be called “nonrandom mating,” which, as I am sure you already know, violates a condition needed for the Hardy-Weinberg equilibrium of a population. There is no other meaning attached to sexual selection. And it doesn’t mean natural selection, either.”HM