Doubting Didymus

Here. It got a bit heated in the middle.

Oolon Colluphid

Sorry guys, Real Life ™ has been in the way for a couple of days...

Crikey, now yer asking! Futuyma has a whole chapter on it, iirc. Will have to check. Meanwhile, I’d say adaptation is the process of genetic change in a population over time (ie evolution), caused by natural selection, which means that the average version of a characteristic is improved ref what it does. (Therefore an adaptation is some feature that has become ‘standard issue’ because it gives its owners a selective advantage in some way over those without it or with less good -- in relation to the environment at the time -- versions of it.)

It’s a subset of ‘evolution’ in general, the bit that causes improvement in function and therefore fitness. And hence, since selection is an ongoing process repeated algorithmically, adaptation is the process responsible for producing what I, at least , regard as all the interesting stuff: the organised complexity that cretinists bang on about: eyes, ears, wings, bacterial flagella and so on.

Doubtless all the other processes that impinge on evolution are interesting in their own right too -- and I do find them interesting. But, Dawkins has argued that the only known natural mechanism that can produce these things is cumulative selection. I haven’t heard of any other; maybe pz and Pinoy have -- and if so, I’d be fascinated and delighted to hear what it is.

Note that therefore there's plenty about evolution that adaptation alone cannot explain -- much of the pattern of the fossil record being an obvious one. Hitting the planet with a meteorite might flummox even the best adaptation.

Adaptation can only explain what it does in a linear, retrospective fashion: that some dinosaurs became birds because there was a niche (metaniche, anyone? micro-environment? What’s the collective noun for niches? A ‘bonanza’, perhaps? ) that could be exploited by being an airborne dino. To which the lineages adapted, by scales becoming feathers, arms (formerly front legs, formerly fins etc) becoming wings. A long line of adaptation, with each increment -- however phenotypically large or small -- utterly dependent on the population's circumstances at the time, plus the proviso that the change is an improvement.

This is why, when explaining how something could be the result of evolution*, Dawkins’s descriptions are “patently linear”. The inheritance involved in cumulative selection is linear! Gould and co can (quite rightly) bang on all they like about evolution being a bush not a ladder, the pace of it, and so on. But that misses the point that all living things today, and all the dead ones that anyone digs up too, are the product of their own evolutionary twig’s long line of contingent adaptations.

Adaptation doesn’t explain why there are tortoises on the Galapagos and kangaroos in Australia: lots of other factors do. It explains what they look like, why they have the form they do. It does not explain why dromaeosaurs took to the air: the environment does. It explains how they did it and how they became something else.

And Gould would be the first to say so: the whole point of his contingent evolution viewpoint is that organisms (sorry, lineages) adapt what they’ve got to start with to the circumstances they find themselves in, as with the panda’s thumb.

The panda’s thumb is the result of contingent evolution. Of environmental circumstances, of available niches. That it’s owned by a sort of bear, not some sort of dinosaur, or... pig... or whatever, is the result of historical accident. And the thing itself is result of a long line of adaptation. ‘Why dinosaurs? Why bears? Why marsupials?’, no. Adaptationism says: ‘Since it happened to be dinos and bears and marsupials, they evolved by adaptation of this, this and this’. It tends to answer more proximal ‘why’s. Not why 'this', but rather given that it is a 'this', why is it like that?

Adaptation does not answer everything. It depends on what the question is.

Note too that it doesn't rely on genes, per se. It depends on inheritance. (I only --deliberately -- included genes in my definition because 'change in gene frequencies in a population over time' is the standard definition of evolution.) It doesn't have to be genes; it just seems that they have something to do with it. But that's a different argument...

* [...when explaining how something could be the result of evolution] ... which is the reason, Pinoy, why Dawkins wrote things like Blind Watchmaker and Climbing Mount Improbable. Note that in both books he uses examples of creationist objections: polar bears being white, bombardier beetles exploding, quoting Hitchens’s Neck of the Giraffe, figs and fig wasps, and so on. The entire point of CMI, and especially the final chapter, is to show, contra cretinists, that such things could indeed logically have evolved through cumulative selection. Not that they necessarily did evolve exactly like that (and I'm pretty certain he says this), but that there is a known natural mechanism that is capable of explaining them. To accuse Dawkins of just-so stories is to miss the purpose of these books completely.

Sure, in “TSG and TEP he unabashedly tries to convert us all to his view of gene-centeredness in evolution”. He also, which you may have missed, stresses that this is merely a different, hopefully revelatory, way of viewing the same thing, that by viewing evolution in that way, some things may become clearer or more obviously understandable. (I’ll get the quote from the start of Extended Phenotype if you wish.) He uses the analogy of the necker cube's face-flips, for added emphasis. He does not claim that it is the only way of viewing things, let alone that it is the only correct way. That many of us do in fact find that way of looking at things useful is only to his credit. It ain't dogma though: take it or leave it.

Cheers, DT

Oolon Colluphid

pz, just to note that I'll get to your points as soon as reality allows. Just to say for now that when we're not talking past each other, we are in agreement, and the rest (on both sides ) may just be hyperbole and rhetoric . Maybe.

DT

RufusAtticus

Adaptation is not a process; it is the result of a process, selection.

Oolon Colluphid

I really must object to this claim of paying lip service to the other stuff. I -- and as far as I’m aware, Dawkins -- certainly do not ignore everything else. Merely that those are the background -- the absolutely vital background -- against which heredity operates. Adaptionists are looking at the heredity -- and may get so bogged down that they forget about the background. These ‘pluralists’ are looking at the background -- which is fine -- and sometimes, it seems, mistaking it for the heredity element itself.

So we are accused of not looking at what we damn well know we aren’t looking at? Where does anyone say that adaptive change is all there is?

Am I right in thinking that the “majority of the genomic differences between any two species are going to be nonadaptive” refers to the masses of non-coding DNA? Well gosh darn, that’s a new one to this pan-adaptionist. But surely if it doesn’t code for anything, if it doesn’t have any effect on the body it’s in, it will be adaptively neutral, invisible to natural selection. Hence birds with teeth genes. It’s there, it doubtless varies in detail from species to species or even individual to individual, and is indubitably part of the whole picture. But the funny thing is, when we’re talking about adaptations and the effects of natural selection, there’s not a lot of point in mentioning it. It’s not overlooked, just irrelevant much of the time.

If you mean something else, please ignore the above and let me know what you did mean.

Hmmm. Difficult to explain. Better give up then.

From what I have heard, neither of those are drastically difficult to explain, for I have heard reasonable ‘adaptionist’ explanations of them both. (Best not get side-tracked into the details of them in this thread though. But for a taster, try Ridley’s Red Queen for an overview of possible reasons for sex -- I’m a tangled-banker personally , and I had thought that JMS had had some thoughts on evolution of sex too at some point, while there’s heaps on altruism in eg Alcock’s Animal Behaviour textbook, and I could have sworn game theory comes in some place there too...)

That theories / hypotheses still need work, and / or areas haven’t been settled, simply keeps biologists employed. There are chunks of physics that are also difficult to explain within the current physics framework too. Should physicists give up, since they are also being wrong-headed?

Now that is news. Personally I know of no such thing. I really must get stuck into Futuyma this weekend. I’ve read a few chapters and browsed much of the rest. But hell, it’s a big book, it’s easy to miss stuff...

(I could have sworn I’ve heard that sort of argument before somewhere...?
< scratches head, tries to remember... > )

Perhaps you have a few metazoan characteristics (like, erm, it doesn’t apply to plants?) in mind? Care to share?

If you say so. Sounds like a touch of hyperbole there though.

So what? I think you’ll find that Dawkins is well aware of pleiotropy. All that matters is that some organisms are fitter than others. It doesn’t matter one whit in the eyes of natural selection what causes that extra fitness, as long as it is heritable. The fitness of the overall organism is what natural selection looks at -- and if the gene that makes a hominid have a bigger Broca’s area also makes it unable to digest lactose, anaemic, have ingrowing toenails and cross-eyes, a cleft palate, above-average high-pitch hearing, more whorls in its fingerprints, a dislike for Mahler and godawful BO, and the 88 or so other effects... then the hominid may or may not survive and reproduce, based on the combined effect on its fitness of all those effects. Therefore, only those genes that are advantageous, irrespective of (or rather in light of all) the effects they have, get passed on. Therefore pleiotropy is a complication, not a problem.

However, since you specifically say that “We also know that most genes are pleiotropic to a ridiculous degree” as an argument against adaption explaining complexity, then to you pleiotropy would appear to be a near impenetrable barrier to any sort of adaption ever coming about. Given the overwhelming effect of it -- that any change in what’s inherited will be swamped by all the other effects -- I wonder how you explain how a wolf lineage came to look like a dacshund?

<shrugs> So?

Ah, semantics. Okay, a lot of it is spandrels. There, better? Of course, if any of these spandrels make the organism less fit, then natural selection will weed them out... unless Darwin was talking through his arse of course. Only the spandrel-encrusted organisms that are not disadvantaged leave offspring. I think this mass of spandrels is being used to misdirect the jury.

Sure. But the only stuff that matters to natural selection is the stuff that does affect, one way or another, the organism’s effectiveness at leaving descendants, ie its fitness.

But it is two artists. One keeps adding stuff at random, the other chips off the bits that make the sculpture worse (as defined by the environment).

Quite right. That is called ‘genetics’.

Sheesh! Next you’ll be telling us that natural selection can’t add new information, only remove flaws. Say, as far as I can see, you are telling us that ‘no new information gets added’. But... that sounds awfully like...

< Thinking... Hmmm.... Immutable kinds.... >

Curious. I’ll have a look in my copy of The Theory of Evolution. I don’t recall it saying much that’s different to what I’ve read in Futuyma though... say, y’don’t suppose that ol’ Doug F is one of dem pesky panadaptionists too...? Holy shit, they’re everywhere!

Sure. May even be relevant for how multicellular life got going, for instance. But this can form a fovea in the middle of a retina of something like an eye, while putting the said retina in backwards, can it?

Further clarification please. That looks rather circular as it stands.

And this is not a different face of the same necker cube, how?

Fascinating. But this can form a fovea in the middle of a retina of something like an eye, while putting the said retina in backwards, can it?

So yeah, there is good, interesting, fruitful research going on in related areas. But here’s a test for any of them: can they make an eye?

TTFN, DT

KC

Maybe I'm just being perverse, but to me, even selectively neutral genes are adaptive, in the sense that they at least meet the minimal requirements of the environment at hand.

Cheers,

KC

pz

If you are going to object to the accusation of paying lip service, you really are going to have to overcome this dreadful habit of announcing that you and your pal Dawkins know all about this other stuff...it's just that the other stuff isn't interesting, relevant or significant, and consists of nothing but "background". In case you aren't familiar with the phrase, that's precisely what lip service is: saying that something is important one minute, then dismissing it the next and ignoring it altogether.

I'll get to the rest of your comment later this weekend. I am not, however, particularly favorably disposed to waste much time on it, since you seem to have gotten it in your head that anyone who endorses anything other than simplistic adaptationist dogma can be safely equated with a creationist, and I've rarely found dichotomizing dogmatists to be educable.

You might want to reconsider your attitude a little bit. You specifically asked for alternatives to selectionism in evolution, and I gave you a list of them; the fact that you were and are still ignorant of them is not an argument that I haven't answered the question. If you'd like, I could give you a long list of books and papers (by real biologists, no less; not a creationist among them) that would give you a start on filling the gaps in your knowledge.

Oolon Colluphid

In case you've not heard them before, here's a couple of phrases to add to your vocabulary: 'from the perspective of', and 'depending on what the question is'. Let me repeat, since you didn't grasp this previously: 'adaptionism' and 'pluralism' are answering different sorts of questions. Therefore what is, and is not, relevant to them differs. Hence the lip service (qv) you pay to natural selection. And hence, as I said earlier, we are talking past each other.

Given your apparent inability to even try and see my point, I'm not particularly favourably disposed to continue this at all. It would appear to be fruitless.

See my earlier post.

Don't know about that, but I have previously found that people with sufficiently low reading comprehension can be safely equated with the term 'moron'. I was not equating the arguer with creationists, but rather pointing to strong parallels in the arguments. I was not saying that... ah no, fuck it, go work out the parallels yerself. If you can't see 'em, you are not as well versed in anticreationism as I had thought.

Ditto, old chap. Exhibit 1:

You did no such thing. You gave a list of other things running alongside selection -- unless you reject selection altogether? -- other factors, and / or other ways of looking at it. That is not, in any dictionary with which I am familiar, what an alternative is. An alternative should be able to replace the other thing. So I repeat: can complexity theory and self-organisation, or anything else you are offering, substitute for cumulative selection in explaining eyes?

Well buggerit, I thought I was answering something . So it's my fault if I don't understand something with which, apparently, I'm unfamiliar, after a dose of your pellucid prose. Ah, that'd be because I'm uneducable.

:notworthy :notworthy :notworthy

Actually, if I seriously thought I'd ever get around to them (given the literal several hundred vying for my attention already at home), I'd say yes. Instead, maybe just one or two?

TTFN, DT

Oolon Colluphid

Fuckin panadaptionist.

KC, in a normal world, I'd have agreed with you. But nowadays it's anyone's bleedin guess.

Oolon Colluphid

Yes and no. Depends on how you look at it. Semantic argument follows :

Yes, it’s the result of the process of selection. But ‘result’ focuses on an end-point. An adaptation is the result of the process. But so also, no: looked at as change across time, there is (or can be) a cumulative load of changes. So ‘adaptation’ itself it the process of getting from one design to another. Eg: when talking of improvements in fitness, one could refer to the process of adaptation that led from scales to feathers.

Perhaps it’s a different level of explanation. There is a 'process of digestion' from eating to defecation; it is no less a ‘process’ in its own right because it is also the result of the processes of chemistry.

And if you’ll excuse an argument from authority, Futuyma refers to it as a process, and <beams smugly> his definition in the glossary is quite similar to mine.

Cheers, DT