Around 1970, biologist Lynn Margulis achieved renown for suggesting, and then showing, that eukaryotic cells originated by a symbiotic union of early prokaryotes, with some engulfing others and then the engulfed bacteria evolving into at least two of the cell’s vital organelles: mitochondria and (in plants) chloroplasts. Although others had suggested this before, Margulis gets the credit for pushing the theory forward, supporting it with biochemical and microbiological data, and recognizing its implications. Later work on DNA sequencing supported her completely. She became famous and was elected to the National Academy of Sciences.
To reword the old political slogan for science: fame corrupts, and huge fame corrupts hugely. This isn’t always true, but if a scientist achieves tremendous fame and adulation, there’s always the temptation to think that what you say on every topic bears special weight and consideration. Such solipsism is especially likely to develop in those who, like Margulis, have to push a correct theory against the entrenched doubt and scorn of their colleagues.
And Margulis has become corrupted in this way. In the last couple decades she’s been going around casting doubt on modern evolutionary theory. She has said, for example, that modern evolutionary biology is “a minor twentieth-century religious sect within the sprawling religious persuasion of Anglo-Saxon biology” and that “Neo-Darwinism, which insists on (the slow accrual of mutations), is in a complete funk.” Since she’s famous, she’s invited many places, and often uses these occasions to dump on modern evolutionary biology. In this respect she may be worse for science than creationists, since her scientific credibility remains high. You may also remember that Margulis “handled” (i.e., allowing it to be published despite dissenting referees) the Williamson paper positing a hybrid origin of the lepidopteran life cycle (caterpillar then adult) through mating of an ancestral volant butterfly with a velvet worm. (The paper was subsequently debunked.) I suspect she forced it into publication because it fits her notion that symbiosis—and I suppose you can consider hybridization as something akin to symbiosis—is the overarching factor in evolution.
Margulis and her son, Dorion Sagan, even wrote a book on speciation, Acquiring Genomes, suggesting that the criticial factor in the origin of species was endosymbiosis. I was asked to review it for The New York Times, but it was so dreadful, so completely ignorant of decades of work on speciation (including observations that reproductive barriers nearly always map to genes, not cytoplasmic organelles), that, although I enjoy writing for the Times, I refused on this occasion. I didn’t want to publicize such a misguided book.
But today I am giving publicity to Margulis’s new six-page interview in Discover magazine. There is lots of dreadful stuff in the interview, including her notion that AIDS is really syphilis, not viral in origin at all. But let’s concentrate on the evolution-dissing, where she sounds awfully like a creationist:
This is the issue I have with neo-Darwinists: They teach that what is generating novelty is the accumulation of random mutations in DNA, in a direction set by natural selection. If you want bigger eggs, you keep selecting the hens that are laying the biggest eggs, and you get bigger and bigger eggs. But you also get hens with defective feathers and wobbly legs. Natural selection eliminates and maybe maintains, but it doesn’t create.
You don’t always get creatures that are so defective under artificial selection: house cats are doing pretty well, so long as you don’t screw with their faces to create Persians. True, many artificially selected species wouldn’t survive in nature, for humans often desire traits that would be maladaptive in the wild. Corn, for example, has been selected to keep its seeds on the cob rather than “shatter”, or scatter them about. Not scattering your seeds is about the worst thing you can do as a plant in nature.
But where on earth does Margulis get the idea that artificial selection shows that “natural selection doesn’t create”? Artificial selection, of course, does create, in that, as Darwin famously noted, humans can mold animals or plants into pretty much anything they like. This shows that combining different mutations can make something new: it can turn an ancestral plant into either a cauliflower, a kohlrabi, a Brussels sprout, or a cabbage (all derived from the same species). And if those changes increased fitness in nature, as for example the combination of traits that turned an ancestral artiodactyl into a whale, why wouldn’t natural selection create something new? The fossil record for the evolution of major taxa attests to this completely—unless Margulis thinks that flippers, feathers, and the like all arose by symbiosis or hybridization. I suspect that she does, which would be a ludicrous and unsupported point of view. After all, that is how, in her speciation book with Dorion Sagan, she suggested that most new species arise.
Margulis goes on to tout punctuated equilibrium—the observation that some evolutionary change in the fossil record happens quickly, while most of the time species are static. The jury is still out on how many lineages really show that pattern, but no exponent of punctuated equilibrum—not Gould, not Eldredge, not my own colleagues here in Chicago—would say that the observation of “jerky” evolution vitiates natural selection. Margulis simply doesn’t understand punctuated equilibrium.
Margulis agrees with the creationists about the inefficacy of selection and of the neo-Darwinist paradigm:
The critics, including the creationist critics, are right about their criticism. It’s just that they’ve got nothing to offer but intelligent design or “God did it.” They have no alternatives that are scientific.
Well, at least she’s not crazy enough to accept god as a scientific explanation. But she is crazy enough to proffer her “alternative” theory, which of course is symbiosis. But think about how we could explain either speciation or adaptation as results of symbiosis—either narrowly construed as engulfing and incorporating a different organism into your own body, or broadly construed as hybridization. If that were the case, major evolutionary innovations would arise instantly, and by “instantly” I mean within a few generations. Yes, that’s what happened when bacteria and mitochondria became organelles in cells, and we occasionally do see the rapid origin of species through hybridization (e.g., the phenomenon of “polyploidy” in plants and “diploid hybrid speciation” in plants and animals).
But these events are not the rule, as Margulis implies, but—with the exception of polyploidy in plants—very rare occurrences. Why do we think so? Because we can see the origin of new adaptations and lineages in the fossil record, and they ain’t instantaneous! Think of the evolutionary transition from fish to amphibians, from amphibians to reptiles, from reptiles to mammals, from theropod dinosaurs to birds, from landlubber artiodactyls to whales. Or the evolution of our own species from smaller ancestors with apelike skulls. Each of these transitions took millions of years, and we can see the changes gradually accumulating in the fossils. If this all occurred by symbiosis—a ludicrous notion on the face of it—you’d see either one or a series of instantaneous jumps creating evolutionary novelty. We don’t see that.
And genetic analysis, which can pinpoint genes responsible for both new traits and new species, invariably shows that these new phenomena are due not to the wholesale engulfing of other species, but to changes in an organism’s DNA. Examples abound: see my own book with Allen Orr, Speciation, for the data on traits distinguishing closely related species.
Finally, Margulis seems to have a special beef against population geneticists:
Darwin was saying that changes accumulate through time, but population geneticists are describing mixtures that are temporary. Whatever is brought together by sex is broken up in the next generation by the same process. Evolutionary biology has been taken over by population geneticists. They are reductionists ad absurdum.
This is insane. Genes become “fixed” (i.e., come to characterize entire species) because they positively affect survival and reproduction. And you can have sets of genes that do the same thing. A gene moving the nostrils of an ancestral whale atop its head, so that they become a blowhole enabling it to breathe while partly submerged, will become fixed. And so will genes that, at the same time, transform the species’ front limbs into flippers. There is no “breaking up” of these good genes by sex—they become fixed at the same time because they’re all good, as are other genes for hair loss, reduction of the hind limbs, losing external ears, and the like. Attacking population genetics as unworkable reductionism really shows Margulis’s ignorance about the field, and exposes her as not a thinker but a demagogue.
Finally, Margulis said something about my Ph.D. advisor, Dick Lewontin, that really bothered me. She characterized him as a money-grubbing scientist driven to take grant money for work that he knows is meaningless:
Population geneticist Richard Lewontin gave a talk here at UMass Amherst about six years ago, and he mathematized all of it—changes in the population, random mutation, sexual selection, cost and benefit. At the end of the talk he said, “You know, we’ve tried to test these ideas in the field and the lab, and there are really no measurements that match the quantities I’ve told you about.” This just appalled me. So I said, “Richard Lewontin, you are a great lecturer to have the courage to say it’s gotten you nowhere. But then why do you continue to do this work?” And he looked around and said, “It’s the only thing I know how to do, and if I don’t do it I won’t get my grant money.”
Well, fortunately I have a good relationship with Dick, and, like Woody Allen with Marshall McLuhan, I have him here behind the sign. And, like Marshall McLuhan, Lewontin affirms that Margulis knows nothing of his work. (Yes, life can be like that!)
I called up Dick this morning and read him Margulis’s quote. He said that it completely mischaracterized his views and what he must have said at Amherst. Lewontin said that he thinks that purely mathematical models of population genetics have largely failed to help us understand the distribution of gene frequencies in nature, because those models often make assumptions that are either incorrect or untestable. So while mathematical theory in population genetics has had some successes, he said, it hasn’t been nearly as useful as we hoped. That’s why, Dick claimed, he stopped doing pure equations and started doing computer simulations, which he considers a more realistic way to see what can happen in nature. In simulations one can vary the parameters more easily and check the models’ sensitivity to varied conditions. In fact, Dick said that ages ago he stopped submitting grants that proposed purely mathematical approaches. So Margulis’s characterization of Lewontin as a dishonest huckster trying to fund work that he knew was bogus is inaccurate and unfair.
Lewontin wanted me to add (for I have permission to quote him here), that his purpose in getting grant money was not simply to fund designated projects described in his research proposals, but to “run an institution”: to “fund a group of creative people to do what they want.” And indeed, that’s what he did—and that’s what many grant-funded investigators do. We can’t always predict how our proposed research will turn out; in fact, we know it will turn out differently from the projects we describe in our proposals. And the granting agencies like the NIH also know this well. In many ways, grants are not just given for proposed projects, but for demonstrated accomplishments of a group of investigators. For many years Lewontin ran one of the most productive groups in modern evolutionary genetics. I was proud to be a part of it.
When I read him Margulis’s statement, designed to denigrate population genetics, Lewontin didn’t recognize at all the caricature she had drawn. Margulis simply distorted his views, which I’ve just described, as another way of dismissing modern evolutionary biology.
When discussing evolutionary biology, then, Margulis is dogmatic, willfully ignorant, and intellectually dishonest. She does deserve plaudits for not only her early work on symbiosis, but for having the tenacity to push for her ideas in the face of considerable opposition. But that tenacity is being misapplied here. She’s simply wrong—and wrong in the worst way a scientist can be wrong: ignoring all the data that go against her theories. But what do you expect of someone who answers the interviewer’s last question like this?:
Dick Teresi (the inteviewer): Do you ever get tired of being called controversial?
Margulis: I don’t consider my ideas controversial. I consider them right.
She’s almost religious in her fanaticism.
I’m not sure what I think about Discover publishing this. The reviewer isn’t critical at all—Teresi doesn’t offer any counterarguments to her specious assertions about evolution, which a good interviewer should do. You could argue that this isn’t 60 Minutes, but a scientific magazine. Nevertheless, Margulis’s interview comes off as unsullied, uncontested, and ultimately unwarranted criticism of modern evolutionary biology (it has, of course, already been picked up by the creationist Discovery Institute). It would seem incumbent on Discover to offer a counteropinion. Otherwise, they’ve acted like a boxing referee who lets a favored pugilist get away with punching below the belt.