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

I understand the quandary a lot of people are in when they try to discuss Evolution and Natural Selection. As a science the discipline must of necessity use precise language to differentiate the mechanisms. This can often lead to confusion, as with MartinV, in thinking that Natural Selection and Sexual Selection are mutually exclusive phenomena. Then add concepts like point mutation, genetic drift, gene flow, insertion, copy error and add group selection, population selection, well, I can see where a newbie will scratch their heads and wonder.With those just getting into the swing of things I always liked to define “mutation” as the all-inclusive process of changing the genome and leave the details to come as necessary. With Natural Selection, I define this as what effect those “mutations” have on the individual and leave groups, populations, etc. for a later time.As for the Hooter’s question, Frog, it is not stupid. There are a lot of knowledge-seekers around these parts and such a discussion could be to their benfit.

The individual is, of course, the one unit that is affected by Natural Selection pressures. Even when major environmental changes occur affecting an entire species some individuals may be better constituted to survive and procreate.The individual is a “suite” of genes acting in concert. The right mix works, the wrong mix dies . as an individual. The effect is that certain mixes of genes survive, propagate and add to the mix in a population. Dawkins’ “selfish gene” phenomenon is the result.Unless, of course, Marty’s spirit force is peckish and decides to make chocolate pudding of everything.

Sure, Hoot, you could go that way. But, I won’t.Yes, genotype + environment = phenotype. All this means, in the grand picture, is that I am me. My “individual” is a unique phenotype based upon a unique genotype. I am a unique mixture of genes. I, the individual, am my genes.To be religious about it, none come unto my genotype but through me.Natural Selection has no effect upon my genes save through its effect upon me the individual. I am blessed by Ol’ Mom Nature to have been conceived as a “fit” specimen of my species. My suite of genes has been found to convey survivability and reproduction of this resultant individual within this environment. Natural Selection did not select against me as an individual (suite of genes) which means a good portion of my genes have been passed on to my progeny. Poor kids. But the point is this, between genotype and individual there is no distinction. We are each, they.Clear as mud, I know, but it sounded good when I wrote it.To argue that selection operates on the gene and not the individual or on the individual and not the gene is incorrect. We are indistinguishable. Dawkins sees a selfish gene. I see an entire suite of selfish genes . me.

I appologise in advance. I'm feeling verbose.Where to start?The beta Globin Gene cluster is one of the most selfish suites of genes in all of mammalian history.“Don’t include me and guess what?...You don’t get to live! You don’t even get to get born!”Bunch of egotistical plicks!Natural Selection doesn’t get to do much with bGGC because all by itself it just kinda lays there on the ground and rots. In a package of other equally selfish genes, however, it can, and periodically does, get to be carried around in a warm living thing with duplicates of itself in other packages comprising other parts of the same warm living thing.Not that bGGC would acknowledge this but in fact without the rest of the package of equally selfish genes bGGC is a rather useless glob of goo of no use to anyone. Other than its egocentric attitude the other major attribute bGGC has is the fact that without it the rest of the package of genes doesn’t get to go anywhere or do anything and just kinda lays on the ground and rots. So bGGC gets invited into all the packages (those that want to go anywhere, do anything and have some fun, like maybe, live) and all the various suites of genes get to show off, strut their stuff and make a furry fuzzy mammal.Now one specific glob of bGGC (we’ll call him Bob) was a bit unique. He wasn’t like all the other bGGCs. He was special. He could make the most efficient hemoglobin there ever was in all the world. He was good. Unfortunately, he also wasn’t very choosy about what package of other selfish genes to go party with. Not that he had much choice, his family is on the “A” list, after all, he did got invited and since all the other parties were getting their own bGGCs he figured he would go so he went. For a while Bob had a grand old time with his pals showing off, strutting his stuff, doing his thing, making copies of himself billions upon billions of times with the rest of the gang until they had themselves a nice furry fuzzy mammal to ride around in.The problem started with Bob’s new acquaintance, Hox. Seems Hox was a bit of a laggard and as it turned out had neglected to copy the plans for that right front leg. Well it wasn’t long before Natural Selection showed up with its glowing green eyes, sharp salivating fangs and Bob and Hox and all the rest of the gang ended up being ripped apart by digestive juices.Now if Bob had been invited to one of those other parties, maybe the one with Hox’s sister Hoxanna, who was as unique as Bob in her own abilities (she was a most brilliant engineer and never forgot anything) that party could have built themselves the strongest fastest bestest furry fuzzy mammal of them all. But no. Natural Selection didn’t know about Bob’s greater abilities, couldn’t care less in fact. All Natural Selection knew was that the furry fuzzy mammal that Bob and his party put together was slow, hobbling and delicious. Regardless of Bob’s unique and superior attributes, the entire gang, all the various suites of selfish genes working in concert with their abilities, created an individual that Natural Selection decided to eat.It is not the individual gene nor even small suites of genes like bGGC that Natural Selection targets. It is the entire package, the individual, that makes it or doesn’t.

Hey Paul, Paul here. I concur.Answering the question “where does Natural Selection occur?” has only one answer: the entire suite of genes of an individual. The effect of Natural Selection occurring on millions of individuals over many generations brings out specific genes, or rather small suites of genes, which appear to become prevalent in a population. To say that Natural Selection, over the long haul, selected for or against specific small suites of genes is not incorrect. But the operating mechanism works on the individual transient package one organism at a time. As I’ve tried to illustrate a few messages above this, we can, and probably have, due to this mechanism, lost some very nice superior suites of genes never to reappear. Natural Selection can promote or destroy superior suites of genes because it can ONLY act on the concerted effects of the whole. Edited by AZPaul3, : Just because.

Good God, man, do you practice obfuscation for the fun of it? Is it congenital? Nested sub-references 3 layers deep, juxtaposed syntax with reference outside the structure or no reference at all, run-on sentences without even the thinnest hint of relation subject to verb . If you've got something to say, Brad, then say it without all the sub-references and do try using some kind of recognizable structure. You are not coming through. Your efforts, and mine in trying to translate, are wasted.You have some kind of problem saying, “I would be happy to discuss my philosophy with you?” Logos my organon, indeed.I do hope this is a written affectation. God help you if you speak this way in real life.

You are, of course, correct. Depending upon what one wishes to accomplish one gets closer to or further from the tree.So to sum up, the mechanism of Natural Selection, in detail, operates at the level of the individual, and in effect, operates at the level of the gene.Hey, Hoot, it's your thread. Whatch ya think?

I would appreciate that very much, Brad. But only if you can structure it in such a way that a poor country bumpkin can understand.

Natural Selection is all elements of an environment that impact an organism’s reproductive success. From changes in climate to big space rocks smashing into the planet, from the beaver’s dam that dries up the stream for the frogs 3 miles downstream to the brilliance or lack thereof of the peacock’s tail. All factors, even luck, good or bad, that impact an organisms reproductive success are naturally occurring, without purpose, guidance or forethought and have what we call a “selective” effect. Sexual selection is but one of these natural selective elements.Because of my genome, my complete phenotype is unbearably attractive to the female of my species. I am 6 foot 6, 200 lbs, with muscles that ripple like waves over a stormy sea. I have the chiseled features of the Greek gods I am descended from and my intellect is beyond all known limits. I am not just sexually selected for, I am wanted, I am needed. I can have my way with any woman and I will father an extensive clan assuring my genes are passed on to the next generation by the dozen. I am selected for by the powers of Natural Selection. Assuming, of course, that I am not crippled in a football game, run over by a drunk driver, hit by a falling comet or that I can somehow survive the pandemic of typhus rolling over the continent and find shelter from the mini-ice age that has gripped my world, otherwise I’m just a dead wannabe who leaves nothing behind having been selected against instead of for by all those other elements of Natural Selection. Now that is a most wonderful run-on sentence. But if the point is made then it works so I don’t care. Fantasy is such fun.

Except a space rock caused such devastation as to exacerbate the extinction of Dinosaurs while, due to its phenotype, some small furry mouse survived. It passed right through this filter of Natural Selection without too much of a problem. I submit its phenotype was the reason why.As you alluded, some frogs survive drought. Some bury themselves in the mud before it dries and, in effect, hibernate until moisture is again present. I submit their phenotype allowed this capability and those species of frog, or even individuals of this species of frog, without such capabilities in their genes, in this instance, did not pass through this filter of Natural Selection. They were "selected" out.Now to the butterfly. This touches on where this discussion wants to go.After, hopefully, establishing the mechanism of Natural Selection operates on the level of the transient individual, now we can look at what this crucible has left us. Why do more than half of the cousins of your poor eaten butterfly survive? Why did this differ from the meager 20% of survivals for this other butterfly population? Different coloration? Different feeding habits? Different types of predators? What is similar about them? What is different? What is different/similar in the phenotype? And, ultimately where this discussion wants to go, what is different/similar in the genotype and why?But first we need to take a step back.I submit that everything that impacts an individual’s reproductive success is an element of Natural Selection from beaver dams to space rocks and all in between including just dumb luck. The interesting stuff is what comes out the other end.Edited by AZPaul3, : Re-phrase.

You are confusing the mechanism of Natural Selection with the result of Natural Selection.The mechanism is upon the individual, the result is upon the population. The former is life or death, the latter is Evolution.

I like that, Hoot. I could use all the checkles I can get. Thanks.But, to the Frog's point: is his example not Natural Selection? Is its mechanism not operating on the individual?

Have it step in front of a speeding semi. The aggregate suite of genes exhibiting "stupid" would be lessened from the population.Hoot, are you looking at Natural Selection as a "process" rather than an event? Are you confusing Natural Selection with its higher level result Evolution?Edited by AZPaul3, : No reason given.

Natural Selection is an agency of Evolution, agreed. Not just an agency but one of the major pillars.OK. Let us start with the gamete. Gametocytes are formed just like somatic cells via mitosis with the usual mixing of the genes that ensues. When a gametocyte undergoes meiosis half the genes end up in each gamete. Which gene ends up in which gamete is pretty much random. Is the formation of the gamete an event of Natural Selection?When 100 million sperm storm up the vestibule to court the ovum (a bit of Dave Berry there) only one can succeed (usually). Is this an event of Natural Selection?As has been discussed here and other threads, (if I recall correctly) somewhere around half of all conceptions are spontaneously aborted, usually due to mutation causing non-viable embryo. Is this an event of Natural Selection?Gestation is fraught with its own dangers dealing with mom’s plumbing, diet, environment, dangers from blood and serum antigens, infections etc. Is birth an event of Natural Selection?Now the individual is on their own in the world. We all know the dangers impinging on life. Is mere survival an event of Natural Selection?Boy meets girl. Girl likes boy. Sexual selection in all its glory. Is this an event of Natural Selection?Repeat all the above.

Modulous: Percy: I’ll take this challenge.I lived in the Denver area for a few years and we used to go out in the fall into the foothills to see the Aspens turning. Among the brilliant golds, reds, yellows and rusts it was difficult to remember that this entire hillside of Aspen trees was all one organism . one individual. In fact the largest single organism on the planet is Pando living somewhere in Utah. Pando is a 6 million ton monster of an Aspen forest that is in fact one tree (Populus tremuloides). It has some 40,000 trunks all connected by an extensive continuous root system. This one organism has adopted a distributed physical form as an individual over the usual concept of what we think as a “tree.” It is instead a forest.If Modulous will excuse me I know nothing of soldier ants. What I do know are Solenopsis geminate . fire ants. If you have ever stepped on a Fire Ant mound and had them boil and roil over your Nikes chewing through to spit their acidic poison into your toes then you know why the name. They are also known as the National Pest of Texas. I know them only too well.The members of the colony come in different shapes and sizes. The forager is the one we usually see above ground out looking for food. Then there are Guards and Tenders and (usually) one queen. Colony is an artificial human distinction. This colony is in fact one organism . one individual. Like the Aspen they have adopted a distributed physical form. But they have taken it further. They have also adopted a distributed physical function and a distributed intelligence. They have also done away with the usual physical connection of blood, bone, skin or root in favor of a complex web of chemistry. A successful body plan, indeed.Your disembodied brain lies comfortably on the bed pillow while in the living room one of your ears and an eyeball rock gently in the Lazy-Boy slowing flipping through Discovery, History, SciFi and ESPN. A kitchen hand (literal) hobbles into the bedroom to announce, “Hey, brain, we’re out of bread.” No problem. Dispatch a shopping hand down the road to the nearest Safeway to pick up a loaf of Split-top Wheat.The success of the Solenopsis geminate body plan is that it can lose a few hundred legs, feet, arms, eyes and just grow them back. The colony as a single individual organism stands to the cauldron of Natural Selection.