This time I’m not going to discuss Jim Shapiro’s misguided dismissal of natural selection (I’m done with him), but, like the Lernaean hydra, when you cut off one antiselectionist head, another pops up elsewhere. This has just happened at PuffHo, where Stuart Newman, a professor of cell biology and anatomy at New York Medical College, has taken arms in support of Shapiro’s views. (He mentions Shapiro explicitly.)
In his new column in the Science section, “Where do complex organisms come from?“, Newman’s answer is this: “Not from natural selection, but from the self-organizing properties of molecules and tissues.” This is a popular answer among contrarians, creationists, and those who know little about evolution, but it’s wrong. It’s wrong because “self-organization” cannot explain adaptations: those features of organisms which have obviously appeared to aid their survival and reproduction.
I’m sure you’ve noticed that I’m losing patience with those biologists who claim that something is deeply wrong with modern evolutionary theory, which needs either a drastic overhaul or a complete junking. Now, it’s clear that there are new discoveries every day that affect our view of how evolution works (horizontal gene transfer is one, the conservatism of gene regulation across long-diverged taxa another), but I haven’t seen anything that makes me think that natural selection is an outmoded way to think about the evolution of adaptations. And yet that’s what is claimed not only by religious people like Alvin Plantinga and philosophers like Tom Nagel, but also by biologists like James Shapiro and Stuart Newman. I’ll start believing them when they show real problems with the idea of natural selection and, especially, propose a credible process that can explain the evolution of adaptations like mimicry, hearts, and flippers.
I’ve divided Newman’s argument into three parts:
Newman’s first contention: natural selection can explain minor evolutionary changes (“microevolution”), but not big ones (“macroevolution”). Sound familiar? That’s a recurring theme of creationists like Michael Behe and Jon Wells. Newman says this:
While it may be an adequate scenario for the refinement of some already-existing characters — the beaks of finches, color intensity of moths — the “microevolutionary” process envisioned by Darwin and his successors does not account in any plausible way for “macroevolutionary” patterns such as the differences between oysters and grasshoppers, fish and birds. In fact, adaptationist gradualism, though still popular in some scientific circles, is increasingly questioned and found wanting by evolutionary biologists working in an expanded set of disciplines. [JAC: Who are those evolutionists? He doesn’t name any.]
But why not? Newman gives no explanation why selection can’t explain macrovolution. And I see no reason why adaptive differences that characterize major taxa, like phyla, must have evolved by a process different from than that changing the beak sizes of finches. Extrapolated over millions of years, natural selection can wreak huge changes in organisms. The evolution of whales from a land-dwelling artiodactyl (even-toed mammal) took about eight million years; this is documented in the fossil record. That’s a pretty short time for substantial change. Our own evolutionary divergence modern chimps and bonobos wasn’t much shorter—it took about six million years—and that involved far less remodeling of the body plan. As the paper of Nilsson and Pelger on eye evolution demonstrates (reference below), one can evolve complex characters in a remarkably short period of time: about 86,000 for a camera eye in their case.
Newman’s second contention: thanks to the labors of developmental biologists and geneticists, we now know that macroevolutionary changes involve saltations and “niche construction” rather than natural selection.
By incorporating embryonic development and its underlying physico-genetic processes into evolutionary theory, investigators are learning that abrupt alterations in body plan and other aspects of organismal form can occur in response to environmental change or gene mutation in ways that affect multiple members of a population and exhibit consistent patterns of inheritance. Furthermore, there is increasing emphasis on the resourcefulness of organisms and their ability to construct their own niches. Having a “phenotype” (the outward manifestation of biological identity), very different from that of one’s progenitors is no longer considered disqualifying for survival.
“Niche construction” is the idea that organisms, by their own behavior, can change the selection pressures on themselves, and in that way forge their own ecological niche. This is a reasonable idea for some (but not all) cases of adaptation. The classic example is the beaver: by evolving behaviors to cut down trees, dam streams, and build lodges, they have constructed a new environment for themselves (the lake and lodge), which undoubtedly exerts new selection pressures on beaver morphology and behavior.
This idea has occupied biologists recently, and is an intruiguing one. But it is not in any way a replacement for natural selection, any more than is the view that the first “fishapod” that crawled on land suddenly, by that behavioral quirk, exposed itself to a bunch of new selection pressures involving living on land. In fact, the idea that many new life forms begin with a nongenetic change in behavior was suggested by the evolutionist Ernst Mayr in his classic 1963 book, Animal Species and Evolution.
Note that natural selection is still a critical part of “niche construction” theory. It’s not a replacement for natural selection, but the view that, by virtue of their own behavior, animals can expose themselves to forms of natural selection that they wouldn’t experience otherwise.
So how does Newman think that “adaptations” or “macroevolutionary differences” evolve? The paragraph above doesn’t give us much help, for the critical first sentence makes no sense unless you’re a Lamarckian.
Newman’s third contention: macroevolutionary differences result from the self-organizing properties of molecules and tissues. Natural selection is not involved.
By the end of Darwin’s life new physical theories were being put forward to explain abrupt and large-scale changes in such materials, and by extension, the character and transformations of organisms and their organs.
Note how the next paragraph, which follows right after the sentence above, does not explain “by extension” how evolution proceeds. It explains, perhaps, how some mechanisms of development work:
Here is a partial list of late nineteenth and early twentieth-century physical concepts that have proved relevant to developmental processes (with the phenomenon they explain, at least partly, in parentheses): dynamical systems (ability of cells having the same genome to switch between different “types”), phase separation of liquids (capacity of embryonic tissues to form several non-mixing layers), chemical oscillations (propensity of embryonic tissues to organize into tandem segments), “Turing-type” reaction-diffusion systems (the formation in tissues of regularly spaced structures like feather and hair buds, pigment stripes, or the bones of the limb skeleton). All or most of these processes (termed “mesoscale,” being most relevant to objects the size and texture of cell clusters), along with several others, are harnessed and mobilized by the secreted products of specific genes during embryogenesis in every one of the animal phyla (e.g., arthropods, mollusks, nematodes, chordates and so forth).
Yes, maybe a “Turing-type” diffusion system can explain how stripes are formed in zebras or reef fishes (we’re not sure about this yet), but that’s a proximate explanation: how the genome produces a phenotype. It doesn’t provide an ultimate explanation: why does the genome produce that phenotype in the first place? And if the phenotype is an adaptation, like the stripes of zebras may be (again, there are ideas about this, but we’re not sure), then you still have to invoke natural selection as a cause of those “Turing-type” patterns, i.e., the particular evolutionary process that has altered the genes to produce such patterns.
Finally, Newman gives a list of observations about evolution that, he says, can’t be explained by natural selection or conventional evolutionary theory. Here it is:
What can the existence and action of such protean generative processes tell us about the origin of organismal complexity? First, let’s look at some of the expectations of the natural selection-based modern synthesis: (i) the largest differences within given categories of multicellular organisms, the animals or plants, for example, should have appeared gradually, only after exceptionally long periods of evolution; (ii) the extensive genetic changes required to generate such large differences over such vast times would have virtually erased any similarity between the sets of genes coordinating development in the different types of organism; and (iii) evolution of body types and organs should continue indefinitely. Since genetic mutation never ceases, novel organismal forms should constantly be appearing.
All these predictions of the standard model have proved to be incorrect. The actual state of affairs however, are expected outcomes of the “physico-genetic” picture outlined above.
ORLY? Let’s look at Newman’s three contentions that supposedly violate the “standard model” of evolution. On examination, none of them hold up.
1. Gradualism. Modern evolutionary theory does predict that complex adaptations (like the evolution of whales from land-dwelling artiodactyls) can’t occur instantly; they take thousands to millions of years. And that’s what we see in the fossil record. Remember, the Cambrian explosion, which produced many phyla still extant today, was not “instant” but probably took between 10 and 50 million years. That is a long time—certainly a time during which selection, if it were strong (as many paleobiologists think), could produce diverse phyla. Just think of all the changes that humans have wrought via strong artificial selection in plants and animals in the last 10,000 years, and that’s only about .03% of the duration of the Cambrian explosion.
Now there is a strain of thought in modern evolutionary biology that evolutionary change can proceed more rapidly and jerkily than people like Darwin thought—that it need not involve a gradual and insensible change in form over millions of years. It can be faster than that, with change sometimes not occurring at all. Indeed, Allen Orr and I were one of the first people who suggested this possibility (Orr and Coyne 1992; reference below), and of course rapid and sporadic evolutionary change was an important part of Eldredge and Gould’s theory of punctuated equilibrium.
Perfect gradualism—the continual and insensible change of phenotype due to changes in many genetic factors—is no longer a tenet of evolutionary biology, though a modified form of gradualism still is (“complex adaptations take time; they don’t occur instantly or within a few generations”). But we’ve seen no adaptive changes in the fossil record or otherwise that force us to reject natural selection as the causal process. A million years is a long time! And we have no evidence that any complex feature evolved instantly (by “instantly” I mean, say, a thousand years).
2. Conservatism of genes. Newman thinks that the long periods of evolutionary time separating major groups predict that there would be no similarity between the genes controlling development among these groups. Yet genes like the Hox genes are generally conserved among phyla separated by hundreds of millions of years. The gene Pax6, for example, controls eye development in both mice and fruit flies, groups separated by nearly 800 million years of evolution. But does this refute natural selection or any tenet of evolution? Certainly not! If a gene is useful in recruiting other genes to produce a feature, natural selection in the form of “stabilizing selection” (selection retaining genes that are useful for something), can maintain them. And Newman doesn’t mention that Hox genes are the exception: the genetic differences between flies and mice involve many more drastically changed or new genes than conserved ones.
3. Evolutionary theory predicts that organisms should evolve indefinitely: “novel evolutionary forms should constantly be appearing.” This is Newman’s most ridiculous “refutation” of evolutionary theory. Whether natural selection causes adaptive change depends on two things: whether a change would facilitate the organism’s reproduction, and whether there is genetic variation for that change. While genetic variation for most traits is ubiquitous, it’s not always true that it’s in the organism’s best “interest” (I’m speaking in shorthand here) to change. Organisms like deep-sea fish, for example, may be well adapted to their environment, and that environment might not change much over time! So why on earth would they constantly be spawning new forms?
Second, it’s certain that a lot of evolutionary change creating “novel forms” is happening, but it’s simply too slow for us to see. The kea of New Zealand may be evolving into the world’s only carnivorous parrot. The hippo may be becoming fully aquatic, and in a few million years will no longer be tied to the land, but evolve into a sort of freshwater whale, like the manatee. If Newman had seen Indohyus 48 million years ago, he’d have said “Why aren’t new forms developing?” But it took the small deerlike Indohyus 8 million years to evolve into modern whales. Humans have been categorizing life for only a few thousand years; evolution takes millions. It’s simply dumb to say that “novel evolutionary forms aren’t appearing.” And does Newman know what is happening in organisms that live in the deep sea, or underground? Where does he get the notion that the production of novel species and taxa has simply stopped?
In short, none of Newman’s three “observations” mandate that we toss modern evolutionary biology on the scrap heap along with the idea of natural selection.
Further, there are predictions that natural selection makes which Newman’s “physiochemical” explanation doesn’t, and these predictions are met. Here are three:
1. If there is no genetic variation, there will be no evolution, for both natural selection and genetic drift require variation for evolutionary change. And this is met: inbred or highly genetically uniform species are resistant to artificial and natural selection.
2. “True” genetically-based altruism, in which genes mandating that behavior sacrifice their ability to replicate (i.e., organisms do something without their genes getting anything in return) should be nonexistent. (“Reciprocal altruism”, like blood regurgitation in vampire bats, doesn’t count, as the organism that sacrifices also reaps benefits.) Indeed, I know of no cases of true altruism in animals outside of humans, where it’s almost certainly a cultural rather than genetically hardwired behavior. Chalk another one up for natural selection.
3. We should not see “adaptations” in one species that are useful only for a second species. One example I use is the presence of nipples on one animal (say, a wild pig) that can be used only to suckle young of another species, say a wild deer. Natural selection predicts that that can’t happen, and we never see such things. In cases where species have “adaptations” that help another species, natural selection predicts that the first species should benefit too. And that is what we see in the many cases of mutualisms like cleaner fish and their “cleanees” or symbiotic flagellates in the gut of termites.
Newman’s final paragraph, which sums up his thoughts, seems impenetrable and garbled to me:
With a 19th century notion of incremental material transformations no longer relevant to comprehending the range of organismal variation that has appeared throughout the history of life on Earth, the other pillar of the standard model can be discarded along with it. Specifically, if, as affirmed by niche construction theory, phenotypically novel animals or plants can invent new modes of existence in novel settings, rather than succumbing to a struggle for survival in the niches of their origin, there is no need for cycles of selection for marginal adaptive advantage to be the default explanation for macroevolutionary change.
Yes, niche construction can create new forms of selection, but by itself does not and cannot create new genetically-based adaptive change. And niche construction can’t always work, because some animal behaviors simply cannot change important aspects of their environment. Does the color of a polar bear’s coat affect the reflective properties of ice and snow? Does the shape of a chamois’s hoof affect the granitic structure of the Swiss Alps? Does the shape of a fish affect the hydrodynamic properties of water? In many cases animals simply must adapt to static and unchanging features of their environment.
At any rate, Newman’s argument for discarding modern evolutionary theory is, like Shapiro’s argument, totally unconvincing. And it irks me no end that PuffHo continues to give voice to such people, misleading the public about the solidity of evolutionary theory.
_____________
Nilsson, D.-E., and S. Pelger. 1994. A pessimistic estimate of the time required for an eye to evolve. Proc. Roy. Soc. Lond. B 256:53-58.
Orr, H. A., and J. A. Coyne. 1992. The genetics of adaptation: a reassessment. Amer. Natur. 140:725-742.
I’ve never understood the macro/micro distinction. Surely, if you add up 3.5 by of small changes you end up with big changes.
What barriers exist to those big changes happening? Wouldn’t fairly small changes to the (say) hox genes result in pretty bug changes in development (for example)
Am I missing something?
…I, on the other hand, would seem to be missing a closing blockquote tag….
b&
This is surely exactly right; I’m a complete dunce when it comes to the understanding of biology, but simple maths tells me that a ‘macro’ centimetre is made up of ‘micro’ millimetres. For someone to propose micro-evolution but not macro-evolution, they’re going to have to propose a mechanism that stops 10 millimetres from equalling 1 centimetre.
Me too.
I’ve been having a bit of a dialogue with Shapiro in the comments over on that other post, and it’s become clear to me that he thinks that “random” and “equiprobable” are synonyms, and he repeatedly suggested that it’s a failing of Evolutionary theory that it has yet to explain abiogenesis. He might be on the verge of retracting the latter, but he’s yet to address the former.
I’ve made the point to him as emphatically as I can that, though I have no doubt that he’s a whiz at molecular biochemistry, he’s repeatedly demonstrating fundamental errors in introductory-level principles of subjects outside of that, particularly including Evolution and statistics — and that it’s those misunderstandings that have led him astray in his attempts to revolutionize our overall understanding of biology.
There may be hope for him, yet, if I can at least get through to him that mastery of one field doesn’t even grant competence in another.
Cheers,
b&
Go, Ben!
“Since genetic mutation never ceases, novel organismal forms should constantly be appearing.”
I have just one comment on an otherwise fairly silly article from Newman: I would contend that we *do* observe novel organismal forms appearing. Both directly and also indirectly in the fossil record.
Of course how you define ‘novel’ and ‘constantly’ matters a lot here.
Mike.
Earth to Ariana: when Cold Spring Harbor schedules a symposium on this, then it’s OK to devote space to it.
That is way too hasty a dismissal.
No it isn’t. You have to explain where the “self organization” that causes adaptations comes from. The only answer is natural selection.
Could it be said in a different way: “self-organization” cannot explain diversity [of life]”?
It hard to imagine how universal physical (or even physiological) laws can produce so much different results without some kind of diversification process. For example, why myelin is seen in sharks but not in lampreys if it results only from a set of “self-organizing” rules equally valid for the two groups?
Desnes Diev
I think you’ve stumbled on an important point.
The folks who are non-natural-selection-ists seem to be lumped into the microbiology world. Seems to me that they’re looking at the problem from the viewpoint of chemistry. Which does, in the main, follow predictable rules — co-valences and all that.
They can’t see the forest for the trees. Or the biology for the chemistry.
From the adaptive activity of homeostatic processes.
That is a non-answer, because homeostasis itself is an evolved phenomenon. Why do you think that when bone is stressed it grows stronger at the stress points, or why fish have mechanisms for “homeostatically” regulating their blood salinity. It’s a result of natural selection. If the activity of homeostatic process is adaptive, it comes from natural selection. Where else would it come from–God?
Homeostasis occurs naturally. For example, it can be found in weather systems.
As best I can tell, Darwinists and discontents (such as Shapiro) agree on the observed facts such as what happens at the molecular level. The Darwinians want to wrap those facts up in a particular story, that of natural selection. The discontents want to see it wrapped up in a different story. The nature of the story to be adopted is underdetermined by the facts.
For the present, the Darwinists will win this fight. Their story is more complete. The discontents will need to flesh out their story, and demonstrate that it has benefits to the researcher that are not found in the Darwinian story. As best I can tell, they have not yet done that. Perhaps they never will.
And catestrophic feed-forward occurs naturally. For example, it can be found in avalanches.
Saying something occurs “naturally” is some contexts does not indicate that it occurs in all contexts. And more importantly, saying something is “natural” doesn’t say anything about the underlying mechanism that produces it. “Homeostatis” is not some transcendental property of the universe, but rather a label that applies to systems that exhibit certain features. And those features arise because of physical processes, not because of “Homeostatis”. Your implicit causality is precisely backwards, and you are reifying a merely descriptive term.
Yes yes yes. +1 +1 +1
Completely OT, but this is how I have felt in certain free-will conversations on this site. I could almost change one word in what you wrote to read:
It’s a little garbled, but I trust the point is clear: “determinist” is a label we apply to physical processes that behave in a certain way, but “determinism” never should count as an explanation for anything.
Anyway, thanks much for this reply!
What does Newman think behavior that results in niche construction is a result of? Perhaps he feels that after millions of years we just woke up one day and decided to build cities. You would think that after an equally long amount of time our bonobos at our local zoo would at least be able to construct themselves a nice house rather than those temporary nests they use. How can one not feel that there might be a possibility that this difference is a result of random mutation and selection creating behavioral change?
This kind of thing makes me see red.
The macro/micro distinction is indeed irritating, and a great favourite with creationists. But by far the more important point is the one made by Jerry that natural selection is the ONLY thing that can explain ADAPTATION. All that stuff about “self-organising properties”, which I associate with the late Brian Goodwin rather than Shapiro, perhaps because I am British, is all very well and might even explain some interesting features of life. But the one thing it can NOT explain is adaptation. It was very obvious from conversations I had with Goodwin that he simply didn’t UNDERSTAND adaptation: was almost oblivious to its very existence. Perhaps because he was trained as a physicist. But a physicist should be well able to appreciate the amazing design of an eagle’s eye or a bat’s ear and echolocating brain. And any of us should be able to appreciate the stunning perfection of mimicry by a leafy sea dragon or a leaf insect. “Self-organising properties” don’t even come close to explaining such wonders. They don’t even TRY to explain adaptation.
I find it telling that so many of these revolutionary contrarians suffer from almost trivial misunderstandings of principles so basic that they’re generally covered in elementary introductions of the topic. As I noted above, Shapiro conflates “random” with “equiprobable,” and he still might think that it is a failing of Evolution that it cannot explain abiogenesis.
I also still haven’t gotten Shapiro to give more than a hand-wavingly vague explanation of why it is that HGT defies evolutionary explanation but sexual recombination works within the theory just fine. He seems to think that it has something to do with species boundaries…again indicating that he thinks of species as some sort of Platonic ideal and not the fuzzy human-imposed label that it is. (“Yellow” and “green” are clear labels, but at what monochromatic frequency does “yellow” stop being “yellow” and become “green”? Similarly, which ancestor was the first human, or the first primate, or the first mammal?)
What’s even more perplexing is that these people generally tend to exhibit at least some competence within the narrow confines of their own fields, indicating that they’re well capable of understanding concepts of all levels of complexity and scope. Why are they so unable and / or unwilling to learn about fields outside of their specialties the same as they did within their specialties before assuming they’re competent to address them?
b&
Religion?
I’m pretty sure it’s because, having done the hard slog in their own specialty, they think they can skip the elementals of their newly chosen subject and go straight to the paradigm shifting. Also, I can’t help thinking they are driven by some underlying philosophy.
JAC asks about the unnamed evolutionists who question the adaptionist gradualism of Patrick Matthew, Charles Darwin and others. Well we can start with Fleeming Jenkin (1867) who considered it likely that coadaptive traits would limit a group of organisms to a “sphere of variation.” To escape the bounds of the sphere something extra was needed. Then there was Francis Galton who likened this to the extra push that should be given to a rough stone to get it to move from one position of stability to another. These ideas were further developed by George Romanes (1886), William Bateson (1909), Richard Goldschmidt (1940), Michael White (1978) and Max King (1993). For a possible biochemical basis please see “The Origin of Species Revisited” (McGill-Queen’s University Press, 2001).
Oh, for Pete’s sake! You think exhuming someone from 1867 can provide a reasoned counter argument to a scientific position in 2012? Sheesh! While you’re at it, let’s hear about how phlogiston is a good explanation for the behavior of gases, or that luminous ether controls the properties of light waves!
Phrenology!
Unnecessarily rude. I read Forsdyke as simply giving JAC a chronological list of the writers who have questioned adaptationist gradualism. The historical development of scientific ideas, ‘right’ or ‘wrong’, is an interesting study.
Thank you thh1859. They say that those who do not read history repeat it. There was much surprise when Mendel’s work emerged in 1900 after 35 years of dormancy. Shouldn’t we at least entertain the thought that the present time might not be different?
Jerry,
Clearly PuffHo is publishing these anti-neoDarwinism pieces in order to lure you into writing for them. They are desperate to have you and will stop at nothing!
…except, of course, actually — you know? Paying him?
Jerry already writes here without pay, and has a pretty good audience who appreciates what he does. Why should he do the same but with the proceeds going to line the pockets of the PuffHo’s advertising department?
When Jerry wants to line somebody else’s pockets, it’s generally the pockets of Doctors Without Borders. I, for one, would rather see it stay that way.
Cheers,
b&
Oh, I wasn’t suggesting that he should •actually• write for them. I know they don’t pay.
Great post, Jerry. And now for the minor bibliographic quibble. You said:
In fact, the idea that many new life forms begin with a nongenetic change in behavior was suggested by the evolutionist Ernst Mayr in his classic 1963 book, Animal Species and Evolution.
Isn’t that idea itself an example of the Mendelian explanation of “genetic assimilation”? Which was put forward by Conrad Waddington in Nature in 1942, and which he noted was also related to the Baldwin Effect (1902) and arguments by Lloyd Morgan (1900). A web search with these three terms:
genetic assimilation waddingtonleads to a number of interesting papers chewing through this history, which also involves people like Shchmalhausen.Can’t type: Schmalhausen (who was from Russia and was in Russian Shmal’gauzen).
Well, I suppose you could call terrestriality a matter of assimilation, though I wouldn’t say the initial behavior (crawling on land from the sea) was “assimilated”! At any rate, I didn’t mean to suggest that Mayr was the first who thought of this idea, though he may have been one of the first to suggest that major evolution innovations are associated with behavioral quirks. But, yes, you’re right: others had suggested this kind of evolution before Mayr.
Off topic, but I wonder if you’re aware that the geniuses at Evolution News and Views are reviewing your book, starting here:
http://www.evolutionnews.org/2012/12/underwhelmed_a_1067011.html
A creationist barfly reviews WEIT, from the sound of it.
Why am I not surprised that Newman sometimes lectures at theological conferences such as this. Is he ultimately being influenced by religious doctrine?
To me, this “self-organization as a driving evolutionary force” idea has theistic evolution written all over it.
Or at the very least, a sense of 19th century Romantic Trascendentalism.
– which is the other side of the question that I asked below.
I have one question for antiselectionists: assuming that natural selection is not the driving force of evolution, how do organisms avoid natural selection? Or do they? If there is no selection, does that mean that with environmental changes, organisms that are now ill-fitted for the new environment still thrive and reproduce? What makes the environment suddenly irrelevant?
Oooh…evil. I like!
Your point is excellent. Any alternative explanation must not only explain that which the standard theory already explains, but also demonstrate that what the standard theory says happens really doesn’t.
Einstein did that with gravity; he demonstrated that, though there appears to be an attractive force between two objects as Newton described, there really isn’t one and it’s instead a consequence of non-Eucllidian geometry.
Those who favor some alternative explanation other than Evolution must not merely come forth with an explanation that is complete unto itself…but it also must demonstrate that there is no descent with variation and / or that environmental factors don’t influence reproductive probabilities, contrary to all available evidence.
I wouldn’t claim that it would be impossible to do so…just that nobody’s even come close yet (especially Newman and Shapiro), and that the odds of doing so are staggeringly, vanishingly slim. And that there isn’t even a hint of a suggestion that such a revolution is called for…at least, with respect to mechanics, we already knew that there were problems with Newton, and there aren’t any such problems with Darwin that we’re yet aware of.
Cheers,
b&
Oh, doesn’t everyone know that natural selection doesn’t apply any more, now we have modern medicine and affirmative action programs… for every species. 🙂
Exactly! This is why I believe that there should be a Law of Evolution or Law of Natural Selection.
Like the laws of thermodynamics, natural selection is inescapable. It *will* happen and there is nothing anyone can do to avoid it.
Mike.
How is a cuckolded bird feeding a cuckoo’s chick not acting altruistically?
It doesn’t realize that it’s feeding another specie’s young. It thinks it’s feeding its own.
Altruism is based on “intent”. If it sought out the cuckoo’s nest and fed the chicks there in addition to its own, that would be a display of something akin to altruism.
What the cuckoo demonstrates is parasitism.
It’s a bird, It isn’t thinking anything. It has a hardwired nurturing need. It sees an egg so it sits on it. It sees a gaping mouth so it stuffs bugs into it.
A genome that produces nurturing behaviour works like a call and response, a reflex. Intent doesn’t have to be involved.
The genome would have to be more complex to avoid altruistic behaviour by developing the ability to tell its own from others offspring. And that doesn’t always work anyway. If I see a cute Bolivian kid in an ad for a charity my brain gets a shot of oxytocin and I want to give money to help him. Our culture doesn’t teach us that kittens are cute, kittens are just cute whether we think so or not.
I’ve never understood the need to explain altruism as an adaptation. It’s more like a spandrel.
Again, being a host to a parasite does not equal altruism. The nurturing behavior that you described benefits primarily the nurturer’s own offspring. The parasite simply takes advantage of the trait that evolved independently of the parasitic behavior.
The same way a dog feeding a tapeworm in its gut is not altruistic. It’s acting as a hosts to a parasite.
*as a host*
The other commenters are partially correct, but the more correct explanation is that it is the cockold that has the mutation and it is the cuckold that benefits from that mutation.
The cucholded bird is not exhibiting altruistic behaviour. It is merely the victim.
Sounds like ‘no true scotsman’ here. You are defining altruistic behaviour as involving intent but why?
By that definition only humans could be truly altruistic and even then only if you believe in free will.
The need to explain altruism as adaptive comes from thinking that it would be selected against otherwise. My point is that it can’t get selected against if it is a byproduct of a more important behaviour, in this case, nurturing behaviour. The only way to mitigate the cost of altruism would be to evolve the ability to tell your own offspring from others and to turn off the responses to the triggers. That would require a more complex genome so altruism is the default position. You don’t need to explain it as an adaptation.
…um, because that’s what the dictionary says?
Kevin again:
What makes you think there’s no selective pressure against parasitism?
Whether or not there is an evolutionary pathway away from a maladaptive trait is irrelevant. There is likely no evolutionary pathway that would, say, grant birds immunity from influenza. Does that mean that these same birds are being altruistic when they’re serving as hosts to the virus, feeding it with their precious bodily fluids? No? Then why is it any different when the parasite is another bird that tricks them into feeding it by mouth?
Cheers,
b&
Novel organismal forms…
You mean like me? As a human being, I’m a unique set of genes. Novel as novel can possibly be.
As we all are.
Of course, I’m not a new species. For that, I would need reproductive isolation, time, and some sort of filtering process that leads to speciation.
…
Something…it’s on the tip of my tongue…
procedural direction? No, that’s not it…amazing delectation? No…
…
Natural selection! That’s it.
One thing that drives me crazy in posts like Newman’s is how opaque the writing style is. I find myself reading through his prose and thinking “huh?” Thank goodness Jerry Coyne is here to translate, at which point I think “That’s what he meant? Yikes.”
As Coyne demonstrates, you can write about these complex topics in a simple to understand manner, with examples to illustrate. You would think a place like PuffHo would want similar clarity in writing.
It makes me think that people read Newman’s ideas and think, “I have no idea what he is saying so it must be profound.”
Or:
“If this young man expresses himself
In terms too deep for me,
Why, what a very singularly deep young man
This deep young man must be!”
W.S Gilbert, Patience
I’m comfortable with micro and macroevolution in my own mind. I consider microevolution as changes in gene frequencies in a population which do not result in speciation. I think speciation is macroevolution, basically microevolution under the right circumstances. I think that speciation and extinction are the core of the history of life on earth.
I think the differences between, say, a human and a pineapple are the cumulative results of a large number of speciation events. We commonly speak of speciation, but never of genusization, or orderization, and the like. Hey, it is speciation all the way down! 😉
What a wonderful post! I wonder where you find the strength to criticise these anitselectionists for just as you’ve knocked down one up pops another? And the time? I notice that this is your 5th post of the day and the 7th of Dec is not over yet! What filled all this time before you had this wonderful website?
We could put this disagreement into starker relief: imagine we terraformed Mars and moved a quarter of the world’s population there once a stable ecology was established.
Needless to say this would represent extreme reproductive isolation with extreme selection pressure (or, I suppose, if we wanted not to beg the question, we could call it “adaptation pressure” or something). Of course, on our part it would represent a huge accomplishment in niche construction!
But it’s interesting just to think about what would happen to species as a result of the smaller gravitational field.
As Brygida Berse notes above, how could they possibly avoid selection in the face of this utterly novel environment? We shouldn’t be surprised to find systems that evolved for life in Earth’s gravity adapting in strange ways for the first few generations, but these are adaptations that can be explained by selection for organisms that have to navigate several kinds of environment. And eventually we’d expect to see new physiology spring up as selection does its silent work.
Or, it just occurred to me that putting it the other way around might be even better:
Imagine a planet with a perfectly uniform environment with regard to climate, terrain, geology, surrounding chemistry, etc., on which life gets going.
Newman seems to be suggesting that due to self organization and niche construction we should expect just as much “macroevolutionary” diversity to arise there as on a planet like Earth.
It’s true that once life gets going this would automatically create some differences in environment, but ecological change as a kind of environmental change has always been easily at home in the neo-Darwinian synthesis, right?
Still, there’s only so much “new environment” that could be created without initial environmental differences.
Arguing that macroevolution doesn’t occur because you can’t see it is like arguing that your children aren’t really growing because you can’t see it happening.
Around Creationists I support the theory of ‘intelligent growth’, where God takes away your children every night and replaces them with almost identical children who are slightly bigger.
Newman’s first contention: natural selection can explain minor evolutionary changes (“microevolution”), but not big ones (“macroevolution”). Sound familiar? That’s a recurring theme of creationists like Michael Behe and Jon Wells.
It’s not entirely a theme of creationists though. Plenty of respectable people argue that macroevolution is more than lots of microevolution. Larry Moran is one of them:
http://bioinfo.med.utoronto.ca/Evolution_by_Accident/Macroevolution.html
Here’s a paper by Douglas Erwin:
http://classes.seattleu.edu/biology/biol491/hodin/erwin2000.pdf
I’m sure you won’t agree with these perspectives, but I think it’s worth pointing out that it isn’t just creationists who believe there’s a bit more going on here than microevolution+microevolution = macroevolution.
Incidentally, Newman published a perspective outlining his views in Science a month or so ago:
http://www.sciencemag.org/content/338/6104/217.abstract
Sorry, but you’re completing distorting what Moran said here. I am discussing whether macroevolution requires more than the processes suggested to cause macroevolution; that is the contention of Newman, Shapiro, and even Steve Gould.
Moran doesn’t agree with that: he thinks that the areas are simply matters of emphasis. I quote from the post you suggest:
and
The only “non-microevolutionary” mechanism suggested by Moran for “macroevolution” is “species sorting”, also known as species selection. It may occur sometimes, but it’s certainly NOT what Shapiro, Newman, and others are talking about. So you’ve completely distorted what Larry said. If you think he believes that macroevolution involves processes ON THE INDIVIDUAL LEVEL different from those causing microevolution, go ask Larry. He will tell you “no,” I’m sure, for he’s been criticizing Shapiro’s view on his website for some time.
Finally, I never claimed that ONLY creationists said that microevolution can’t explain macroevolution. I just said it’s one of their common themes. Of course others make the same contention, and by and large I think they’re wrong, except insofar as “species selection” occurs (see the last chapter of my book Speciation with Allen Orr).
Well, my point was that sensible people believe that there is a useful and meaningful micro/macro distinction. I suppose that point is a bigger one than your specific discussion and I should have made that clear.
However, I don’t think I’m distorting Larry (at least not in support of my general point). He is, as you note, advocating an additional mechanism (species sorting). Moreover, when you say that Larry is really just talking about a difference in emphasis, I think you are downplaying his position slightly:
All of those things are part of the domain of macroevolution and microevolution isn’t sufficient to help us understand them
To some extent his argument is semantic, but my reading of him is that he does think that there is an interesting debate to be had here. For example:
There is legitimate scientific debate about whether macroevolution is more than just lots of microevolution or whether macroevolution encompasses mechanisms not seen in microevolution. It’s the sufficiency of microevolution argument.
http://sandwalk.blogspot.co.uk/2007/11/with-friends-like-this.html
And I’m aware that Larry isn’t a fan of Shapiro – nor am I. I think his views are vacuous wibble. Newman is a bit more interesting (that Science piece is worth a read), even if I don’t particularly agree with everything he says. Although Larry isn’t a fan!
http://sandwalk.blogspot.co.uk/2012/10/science-journal-publishes-more.html
It’s rather unfortunate that Stuart Newman has decided to garb his interesting work in antiselectionist rhetoric. I have found his work (along with Gerd Muller) to be the most interesting aspects of evo-devo thinking.
Here is an article I found quite fascinating that others may want to look into: http://onlinelibrary.wiley.com/doi/10.1002/jez.b.21066/abstract
Doing a quick ctrl+f for “selection” gave no hints that there was an antiselectionist agenda behind it either.
Jerry:
You might be interested in your mention in my latest blog:
Systems Philosophy Strikes Again!
http://thescientificworldview.blogspot.com/2012/12/systems-philosophy-strikes-again.html?utm_source=feedburner&utm_medium=email&utm_campaign=Feed%3A+blogspot%2FihBUb+%28The+Scientific+Worldview%29
Sorry for the critique. I love your blog and support (mostly) all your great work. Your blog is about the best one on the Internet and the only one I follow “religiously.”
Glenn