Cornelius Hunter seems very confused.
…This brings us back to the UC Berkeley “Understanding Evolution” website. It abuses science in its utterly unfounded claim that “natural selection can produce amazing adaptations.”
In fact natural selection, even at its best, does not “produce” anything. Natural selection does not and cannot influence the construction of any adaptations, amazing or not. If a mutation occurs which improves differential reproduction, then it propagates into future generations. Natural selection is simply the name given to that process. It selects for survival that which already exists. Natural selection has no role in the mutation event. It does not induce mutations, helpful or otherwise, to occur. According to evolutionary theory every single mutation, leading to every single species, is a random event with respect to need.
He has forgotten what “adaptation” means. Of course he is correct that “Natural selection is simply the name given to [differential reproduction]”. And that (as far as we know), “every single mutation …is a random event with respect to need”.
And “adaptation” is the name we give to variants that are preferentially reproduced. So while he would be correct to say that “natural selection” is NOT the name we give to “mutation” (duh); it IS the name we give to the very process that SELECTS those mutations that promote reproduction. i.e. the process that produces adaptation.
Cornelius should spend more time at the Understanding Evolution website.
ETA: CharlieM points out below that…
When CH says that natural selection does not produce adaptations he is talking about individual organisms. He is discussing mutations in individuals and adaptations in individuals. Natural selection has nothing to do with the first appearance of an adaptation in an individual.
And that of course is the confusion – I hadn’t seen just where Cornelius’s confusion lay. Because, of course, the term “adaptation” is a population-level concept. At the level of the individual, the equivalent would be “advantageous mutation”. And that makes the Understanding Evolution website absolutely correct.
Great. Gravity participates in building adaptations. So does the sun.
Natural selection itself is an abstraction because no one knows the actual underlying causes and probably cannot know them.
Abstractions don’t build anything.
🙂
Lizzie,
Darwin’s choice of the word “selection” is metaphorical, but natural selection as a concept is not merely a metaphor. This is clearly a definition:
Lizzie:
Nothing is “missed out”. We still have heritable differential reproduction, and it’s still extremely important. It’s just that “heritable differential reproduction” isn’t synonymous with “natural selection”, contrary to your claim:
Lizzie,
Sure it is. All offspring are viable, and every organism has the full opportunity to grow and reproduce. None are selected against.
It also supports slow breeders. All of the offspring survive, whether they are fast breeders or slow breeders.
They are offered to both strains, and both strains benefit. The mutant strain outgrows the original strain, but that is not because of selection — no offspring are being selected for or against. They all survive.
Limit the resources, and now you have a Malthusian competition in which selection kicks in. Some organisms will survive and reproduce. Others won’t.
From your Darwin quote:
If nothing is ever rejected, it isn’t selection by Darwin’s definition.
Think about Darwin’s pigeon breeders, who selected which birds to breed and which to reject. Nature also selects some organisms and rejects others. If every pigeon is allowed to breed, you don’t have artificial selection. Likewise, if every organism survives and reproduces, you don’t have natural selection.
Um, yeah, that’s right, because gravity and sun are part of the environment in which heritable variation within a population can either thrive or `not thrive so well; and the specific environmental sieving apart of the thrivers from the non-thrivers is what we’ve all called “natural selection” since Darwin identified the term; and the interesting (sometimes quite complex!) packages of traits which have been built in like a Bingo score by successive calls of NS are what we all call “adaptations”, a term which long predates Darwin.
Do redwood trees have short skinny trunks in your world, Mung?
No, I guess not, not in a world where you take every thing so goddamned literally that you understand no thing.
Are you saying I don’t even understand the difference between literal and figurative?
😉
Natural selection is a concept. It’s not a cause. It’s not an effect. Most of the disagreements about natural selection are precisely because what I just said is in fact true.
There are at least two ways in which natural selection can be used. One is as an abstraction offered in place of ignorance of the actual details. Another is as an abstraction offered in place of all the tedious details. Neither use should be taken literally, reifying the abstraction.
See, I do know the difference.
Okay, good!
Yes they are. Now that the original genotype is outbred by the new, their prevalence decreases. Their selection coefficient, relative to the new lineage has dropped from 1, when they were identical, to .5.
The population is now dominated by the fast breeders. They started off as a tiny proportion of the whole, and they will rapidly approach 100% of it.
You have an environment that selects for rapidity of breeding, because there is no scarcity.
keiths, I suggest you are applying the word “select” too narrowly.
The sense in which natural selection “selects” is that the environment biases what goes into the next generation. In an environment in which all variants had an equal chance of leaving their genotypes in the next generation, we would say there is “no selection”. In your example, the environment hugely favours genotypes of the fast breeders – they are over represented in the next generation relative to the previous generation.
It does so because there is no penalty, in your environment, for fast breeding. If a yet faster variant emerges, it will rapidly reach near 100% of the population.
You can call it selecting “against” slow breeders or selecting “for” fast breeders” – it doesn’t matter. Selection is relative, in normal as well as biologica usage. We choose one thing in preference to another. Your environment always chooses the offspring of the fast breeders.
A different environment may favour the offspring of the slower breeders. Replication rate is not always the same as fitness, otherwise slow breeders like us would never have evolved.
Yes you do. You have selection of those that reproduce fastest.
You are thinking of absolute numbers. Evolution is all about prevalence.
William J. Murray,
‘Equivocate’: “use ambiguous language so as to conceal the truth or avoid committing oneself.”
Maybe this is a US-UK thing, because I’m not convinced WJM knows what equivocation means either. It pops up regularly in these conversations, in accusatory fashion, but frequently just seems to serve the purpose of helping separate the beginning of the post from the end. ‘Nice equivocation’, as Joe G is fond of saying.
Mutation results in variation. NS operates on variation. Take away variation (which includes RM) and NS stops. There isn’t another meaning of ‘mutation’ or ‘variation’ at work here. Variation is simply a broader term that includes mutation.
William J. Murray,
Not if you then look up ‘natural selection’ in the same glossary:
Anybody marginally ‘misled’ by the first statement can soon have their misunderstanding corrected by the second. At a population level, NS ‘fashions’ the adaptation from the variation, by differentially removing that variation which isn’t it, iteratively – the output of one round is the input to the next. If there was no variation, there would be neither NS nor adaptation. If there was only variation, that which came to be an adaptation whan NS got its paws on it would be in there somewhere, indistinguishable from its fellows. But actually, only the very first mutation of a series. If a feature is ‘tuned’ by repeat rounds, that final genotype was not there at the start. It got there through NS. Oh, and RM.
You’re right – you do need variation (mutation) and NS, if you haven’t included variation-generation in your definition of NS (which I tend not to). Your concern for pedagological exactitude in teaching of evolutionary theory is laudable. Berkeley is but one institution; there are many to go at, and life is short. To the Interwebs!
William J. Murray,
So, I’m glad we agree on something, but we are not agreed that ‘destruction’ is an accurate portrayal of NS’s overall role. It is merely removing variation. Drift is doing that too. When they’ve eliminated the variation, they stop.
Lack of variation is a problem for a species, and not just for evolutionary reasons. But what you do by turning off RM is destroy any possibility of novel beneficial variations. To then gleefully point the finger at NS for the problems subsequently encountered is to miss the point.
Elimination of variation is a good thing when the variation that is eliminated is less beneficial than that which is retained. And that is exactly what happens when a single-copy beneficial mutation ultimately becomes fixed. If the resident variant is ‘less fit’ than the new one, then the new one will tend to be preserved and the old eliminated. The asymmetric view of a symmetric process is very common among evolution opponents. NS does both things at the same time – eliminating detrimental alleles and promoting beneficial ones is a simultaneous process – the one is always beneficial/detrimental with respect to the other.
All that happens when you turn off RM is that all new variants, good and bad, are turned off. The dire consequences are consequences of reproduction in a finite world, not NS per se. Reproduction eliminates variation, slowly but surely. NS is but a part of that.
I still hold that the tradition of regarding “RM” and “NS” as discrete processes lends itself it misunderstanding.
That is why, pace keiths, I prefer the formulation for Darwinian evolution (i.e. adaptive evolution) as something like
Adaptive evolution to an environment occurs when there is heritable variance in reproductive success in the current environment.
That leaves open the question as to the origin of that variance (which could be random or non-random mutation, and it could be novel variants or a big pool of variance that has been there for many generations), and even the mechanism of heritability. It also makes it clear that not just any old heritable variance will do – it has to be linked to reproductive success, and that it has to be in the current environment.
It’s that link that is key. It doesn’t have to be there at every round, as AVIDA shows, but without at least some links between heritable variance and reproductive success, complex adaptive features won’t evolve.
keiths,
No, there is selection, since selection only means there is a causal relationship between reproductive output and a genotype. Resource competition is but one kind of selection. A is producing an average one ‘offspring’ in the time it takes B to produce 0.5. It’s twice as fit.
Mung,
You wish. Natural selection is about differential birth and survival rates, which I would suggest are real, unless you have evidence to the contrary. You don’t need to know every specific cause of every atomic event before it can be substantially more than ‘an abstraction’, but a real phenomenon with real causal power in the world. Programmers use it. People make money out of applications using it. Breeders have been doing something very like it for thousands of years. Obviously, not ‘natural’, but variants of the same fundamental process.
Elizabeth,
Get back to marking! I’ve seen threads like this go on for months!
It’s actually alarmingly easy to demonstrate that.
I just uploaded a dead simple simulation in Excel, here.
The starting population is the top row of letters, in which each of the four possible genotypes, A, B, C, and D are equiprobable (the very top row is just the random numbers that select the starting population)
In each subsequent row each parent leaves one child or sometimes twins. If your neighbour has twins, one of their twins will eat one of your children.
As you can see, simply by reproducing with random chance of your children being eaten by one of your neighbour’s twins, variation is rapidly destroyed. By the bottom of the spreadsheet, there is usually only one genotype left.
There is no natural selection in this model.
Yeah. I’m over half way!!!!
Elizabeth,
Yep, we had a bit of fun with drift a bit back; you may not have seen it. There was some interesting discussion in the prior threads.
Will check it out when this marking is done!
Oh, I must update the text on that 🙂
eta – edit frenzy – ignore me!
EL said:
Are you joking here? Surely you realize that just because a thing is essential to the production of some other thing doesn’t mean the first thing produces the second thing. Do I really need to provide an example?’
In any event, I’ve made my case to my satisfaction. Looking over that site, I now see it also has a lot of egregious ideology masquerading as scientific fact as well. It really is a pitiful site.
No, I’m not joking. I think that you are doing the very thing you accuse the other “side” of doing – taking the least charitable possible interpretion of a simplified lay explanation.
If A+B is essential to produce C and A alone does not produce C, it is perfectly reasonable to say that B produces C.
I also note that you have completely ignored the points I and others have made about how NS results in the building up of sequences in the same individuals, resulting in phenotypic features that would not otherwise arise (apart from your bizarre infinite monkeys point).
Perhaps you’d like to revisit that on the new thread, which actually deals with Lenski’s AVIDA program – the one that demonstrates unambiguously that without NS, complex adaptive features don’t arise?
William: as someone who claims only to believe what you experience personally, how are you distinguishing between “scientific fact” and “egregious ideology”?
You don’t, as I understand it, believe in “facts” at all. So can you give an example from that site of what you think is a piece of “egregious ideology masquerading” as “a scientific fact”?
What do you regard as a “scientific fact” anyway?
Personally, I don’t like the word “fact” though I think it’s reasonable in lay use. In science we have data and we have models. When our models are so well supported by data we can informally regard them as “facts”.
So I guess probably some of what you are objecting to is a model you don’t think is as well supported as scientists in general do.
But on what basis do you make that determination?
Heh. Care to precis that case?
Perhaps it would be informative to know what you would have written instead? Perhaps provide a quote and your more accurate version of same?
Why would this require a demonstration in software? I thought you’ve been arguing all along in this thread that it’s true by definition.
Adaptive features, are, by definition, produced by NS. However, “complex adaptive features” – the very features ID proponents tend to regard as beyond ID to produce – are demonstrably produced by NS in AVIDA, including IC features by both Behe’s definitions of IC.
It would help William understand why his claim is wrong I believe.
I dunno – Behe still doesn’t get it. Or, if he does, I’m not aware that he’s said so.
William,
Heh.
Yet you haven’t responded to this:
However, your argument in this thread has consistently been that all adaptations are complex, having been built up over time by natural selection.
If we are having our cake and eating it too are William and I invited? 🙂
huh? Yes, that’s correct. All adaptations are exactly the same complexity as each other, without exception.
Mung,
That‘s how you read it? Yikes. What we have here is a failure to communicate.
OMagain,
I wouldn’t bet on it!
The software would be ideologically tainted software, and not to be trusted.
No, it has not, Mung. I’ve given actual examples of single mutation adaptations.
What I have said is that many of the paradigm cases of adaptations (fins, wings, eyes, chameleon skin) are complex, and “built up”, or, simply built up, over generations, from variants in many different genes, through natural selection, which has the property of aggregating them in the same individuals.
Feel free to go back and check.
🙂
Elizabeth, if you’re agreeing that adaptations exist that were not produced or built up by natural selection I won’t object. Have you been having back-channel discussions with C.H.?
No. By definition, an adaptation is produced by NS. And a complex i.e. polygeneic adaptation is, I would say “built up” by NS. As I’ve made quite clear.
Allan Miller said:
Keiths said:
The funny part here is that both AM and Keiths admit that I am factually right here – that it is only RM that actually, “technicallly”, “exactly” “adds to the structure” of the adaptations. They seem to think that it is okay to point at that which doesn’t actually, technically, exactly add to the structure and give it credit for building the structure, without mentioning in that statement or definition that which does actually add to the structure.
Talk about defending the absurd. Any definition or statement about what it is that builds adaptations should begin with RM, and NS should be characterized in a supportive role. Period. Because that’s the facts, Jax.
Lizzie,
We don’t appear to disagree on the mechanics of evolution — our dispute is over which aspects of the process should be subsumed under the term “natural selection.”
I have to go with Darwin on this one. He coined the term, and his definition should prevail unless there is good reason to alter it.
You wrote:
I’m applying it the way Darwin did, and it seems to be working fine.
And in this case the environment is applying no bias at all. It is perfectly hospitable to both variants. Each offspring survives. Nothing is selected for, and nothing is selected against.
There is also no penalty for slow breeding. Each offspring survives and breeds. The slow-breeding variant doesn’t “care” that the faster-breeding variant quickly outnumbers it because there is no competition for resources. There is no penalty for breeding slowly because resources are unlimited.
It also always chooses the offspring of the slow breeders. The environment shows no preference for one over the other. There is no selection, by Darwin’s definition.
Darwin:
Nothing is rejected in my scenario, and everything is preserved. There is no selection, by Darwin’s criteria.
Darwin:
There is no “struggle for life” in my scenario. Each offspring lives and reproduces. Again, there is no selection by Darwin’s criteria.
William,
Look in the mirror, dude.
By your logic, a woodworker turning a table leg on a lathe hasn’t produced anything, and the brick carrier, joist sawyer and foreman aren’t involved in building a house.
Yes.
I disagree that his description excludes your scenario. More to the point, population geneticists have got there first, and they call it selection.
So I think you’ve been ninja’d.
Well, no. It would be like saying:
Any definition or statement about what it is that makes applause should begin with the right hand, and the left hand should be characterized in a supportive role. Period.
Why don’t you join the new thread, William? It’s about a study that shows definitively that without NS, not is there no adaptation by definition, but that NS is the aspect of the process by that brings together the components of features that requires multiple components.
You can quibble with words all you like, but doing so appears you to be preventing you from seeing the point that these words are trying to convey: that natural selection can produce complex functional features that do not occur in the absence of NS – not in a billion monkey-years.
Lizzie,
Um, Darwin got there first, so you and the population geneticists have been ninja’d.
Selection coefficients were invented to try to capture something about natural selection, not the other way around.
Selection coefficients match up with selection pretty well in real life, where there is abundant competition. In my (purely hypothetical) scenario they don’t, so I argue that Darwin’s definition should take priority.
“The means of production has two broad categories of objects: instruments of labour (tools, factories, infrastructure, etc.) and subjects of labor (natural resources and raw materials). If creating a good, people operate on the subjects of labor, using the instruments of labor, to create a product; or, stated another way, labour acting on the means of production creates a good.”
So maybe it would take two billion monkey-years.
Well, I think you are wrong on both counts. I think Darwin’s concept covers your scenario. But we will have to agree to differ on that.
And in any case, as I said, the term is already in use by population geneticists in a manner that covers your scenario, so if you want to be a Darwin Literalist, you’d better take it up with them.