Is there more than one definition of natural selection?

Care to count thy ways? Make a list? Let's see, there's:1. Darwinism2. Lamarckism3. Creationism4. Disneyism...”HM

RAZD writes: Does NS “operate” on the phenotypes of individuals, like a surgeon who operates on a patient’s liver? Or does it “operate” instead on the reproductive success of populations? NS engages when that success is not uniform across individuals? I think there is a cause-effect relationship to consider here. Is NS a cause or an effect? Neither? Both?Here's how I see it. NS, in and of itself, does not occur at the individual level. NS is about a population’s differential reproductive success. You can’t have evolution occurring in individuals, only in populations. Whatever alters a population’s uniform success in reproduction may have multiple causes”environmental factors, mutation, gene flow”and NS may not always, or not even often, play the lead role in evolution.This issue seems like old dirty laundry to me. Why haven't we cleaned this up?”HM

cf wrote: crash, I don't think so. I think this notion is a large part of the confusion about what exactly NS is.”HM

RAZD wrote: I simply do not understand that statement. So, NS occurs where exactly? In the population or in the individual? I don't entirely get this. Who ever said that, anyway? All any individual can do to affect evolution by NS is to make gametes and have sex hopefully. Meanwhile, evolution by NS goes on in the population. Indeed, the selection of beneficial alleles in that population is what is really going on, I think.btw: As I'm sure you know, Darwinian evolution by NS was postulated on the Malthusian principle: Populations often produce more individuals than available resources are able to sustain. The whole thing rides on a train called Population. Individuals do not have to go through Door #1 marked "Naturally Selected" or Door #2 marked "Naturally Not Selected" like quiz-show contestants.”HM

crash, I like your weebles but I have just addressed this issue in my comments to RAZD in Message 236.”HM

RAZD, if you have an experimental human population of four individuals”Nancy, Jack, Judy, and Frank”and NS came calling, please tell me exactly how it would “select” amongst those individuals? What happens when an individual is “selected”? Does it get to survive? To mate? Can’t “unselected” ones do those things, too? And please tell what a “selected individual” means to the course of evolution. If all four individuals got “naturally selected” in an evolutionary event, but afterwards a bear came by and ate them, would they have been “unselected” by the bear?You are far better off, IMHO, to let NS have its way with populations than to say that individuals are the ones being selected. Individuals are only the carriers of beneficial, neutral, and harmful alleles. Individuals do not move forward in the course of evolution, but alleles do. Therefore, NS “selects” for the alleles in a population, not individuals. There has never been an individual anything that has successfully evolved into something else. There was never an individual fish that evolved into an individual amphibian. That kind of morphing goes on in populations when their alleles get sorted out.”HM

cf wrote: But where to the individuals go in the course of evolution when that are "naturally selected"? Through Door # 1 to lay down and have sex? Don't unworthy or undesirable individuals sometimes get to have sex, too? Please see my post to RADZ above in Message 240”HM

No! The "naturally un-selected" individuals often get to do that, too. Think about Rwanda. “Naturally selected” means that a population has experienced differential reproductive success. There are no NS agencies going around picking out individuals who qualify to have sex and then makes a bed for them; that's more like "sexual selection." NS, instead, is going around populations of individuals picking out alleles that are disproportionately favored when that population is undergoing differential reproductive success.”HM

cf writes unwisely: If individual A is selected to mate with individual B and they successfully produce offspring, neither one of them, as individuals, will evolve by NS into their offspring. Of course you know that. What actually is selected and what actually evolves is that complex of alleles mixed together from individuals A and B, which in combination somehow succeed to make other successfully reproducing individuals. So, you see, individuals can only live their effemeral lives and die without ever experiencing the joy of evolution. They don't get to go to Darwinland. But their alleles might have that pleasure, if they are good enough.Please, once again: No individual can be selected by NS or evolve by NS because every single individual lives but one life.*I think RAZD is mostly right about phenotypes being selected by NS. And phenotypes mean genotypes, of course. NS works on those phenotype/genotype complexes, not on the individual carriers of them.It may be worth noting here that very few phenotypes are carried by individual gametes when they unite in fertilization. For this reason, I see genotypes and their alleles as the true loci of evolution by NS.”HM*Why don't you get this, yet?

Ahhh, please read my words again. I never said "Evolve into NS."That's downright shabby! You ought to be whipped with a cane. Nah, I ain't goin' back there. I've been to the weebles. Done that. Now I'm going to TVeebles to watch pro football. Go Seahawks!”HM

[Seahawks...ugly. Booo!] That one goes into your permanent record. And it's not the first one, either! Without resorting to the weebles, I think it is fair to say that NS uses individual organisms as software stores, stocked with beneficial alleles, from which it makes its selection. Remember, individuals are not the ones that evolve. Individuals die early and become dirt. But their alleles, even without much phenotyplcal protection by haploid gamete cells, are the things that actually get selected by NS and survive an evolutionary event...and they survive their host organisms many, many times over.crash, what's the point of NS selecting an individual if it is certain that the individual will die? You're looking in the wrong place to find the survivability meaningful to evolution by NS. Evolution by NS happens when a population fixes new beneficial alleles in some significant way. Your individuals can be selected by each other to have sex, of course, but this is not the same thing as NS, this is only sexual selection. All any individual can do to participate in NS is to make gametes, have sex, and die. Meanwhile, down at the genome ranch, what is really being naturally selected are the beneficial alleles of a population.”HM

crash, you are confusing sexual selection with NS. Sexual selection happens when there is disproportionate mating amongst individuals of a population. NS happens when there is differential reproductive success across individuals of a population. Nah. You're talking about sexual selection”differential mating success. That's not what NS is. And I can only see your individuals as perfunctory camels, carrying their allelic burdens to a marketing oasis, where their cargoes will be selected like dates for their usefulness and desirability.”HM

crash, I don't think you understand what NS really is. NS arises from the differential reproductive success amonsgt individuals across a population. Differential mating success may or may not leading to NS. There is no rule that requires sexual selection to lead to NS. They are two different things. Sexual selection may go on in a population without any NS occurring at all.btw: I wouldn't be too distracted by the word "natural" in NS. It was put there by Darwin to differentiate his theory from "supernatural selection," if you will, or otherwise "Creation."”HM

While I certainly do agree that some kinds of sexual selection can lead to evolution by NS, I cannot agree that sexual selection and NS are the same thing. There is no reason I know of that requires sexual selection to automatically invoke NS in a population.I don’t really know if anyone has even postulated this before, so here goes nothin' . Why couldn’t sexual selection be a means for a population to avoid NS? If sex was invented as a means for a genome to avoid its genetic parasites, then why couldn't sexual selection have been invented as a means for a population to avoid the trouble of NS? Hey, if you've got an allele for a big, ugly nose, who's going to want to mate with you? Sexual selection, then, would certainly not seem not to favor NS in the direction of big, ugly noses. Ay?”HM

Let's test my proposition that there can be sexual selection without NS:In a hypothetical population of 100 individuals”50 males and 50 females”the good-looking ones go first and rest mate up with what’s left, but everybody is happy. That’s sexual selection, pure and simple. Now, the good-looking ones and the bad-looking ones have equal fecundity in this hypothetical population; each couple has exactly one girl and one boy. Everybody in the population has reproduced with equal success. So, in this scenario, there was sexual selection without NS.If you can’t eliminate this scenario from the realm of possibilities, then you can’t prove that sexual selection is the same thing as NS.”HM