More misguided critique of the modern theory of evolution—in Skeptic magazine

A recent Skeptic magazine features George Levine’s review of a new book by Jessica Riskin: The Power of Life: The Invention of Biology and the Revolutionary Science of Jean-Baptiste Lamarck. It’s about the life and accomplishments of Jean-Baptiste Lamarck (1744-1829), one of the first naturalists to suggest that life evolved from earlier (and simpler) ancestors, and by natural processes.

Biologists largely know Lamarck from his having been wrong. Yes, organisms did evolve, but Lamarck got what drove evolution completely wrong. Instead of the better-adapted individuals in a species leaving more offspring, which was Darwin’s theory, Lamarck posited that evolution proceeded by two means:

a.) A teleological drive in organisms to become more complex, and

b.) Via the inheritance of acquired traits. That is, organisms somehow became more adapted to the environment through their own activities, and these acquired adaptations were passed on to the next generation. The classic example Lamarck gave—and one now used to debunk him—is his scenario of how giraffe’s got long necks. Originally, he said, giraffes had shorter necks, and had to stretch their necks to reach leaves higher up on trees.  That stretching made their necks longer, and, as this process continued over generations, giraffes got their astoundingly long neck. Their striving to reach leaves had somehow become inherited.

We know now that Lamarck was wrong on both counts. First, there is no teleological “drive” to become more complex (nor do all lineages become more complex: tapeworms, for example, lost nearly all their organ systems). Further, acquired traits are not inherited. Although Darwin mentioned that briefly, his alternative theory of natural selection (see below) was pretty much on the mark.  New suggestions that epigenetically acquired modifications become inherited fail on two counts: they are erased from the genome in a few generations, and they do not lead to adaptations. In fact, as in the case of the “Dutch Hunger Winter” of 1944-1945, epigenetic modifications of the DNA acted in a way that was maladaptive, raising the incidence of disease among descendants. Eventually, those environmentally-induced epigenetic changes in DNA disappear, as they always do when epigenetic modification is not itself coded by the DNA.

In the end, Lamark’s “theory” of evolution came to nothing and his work was largely ignored.  According to the Skeptic article by George Levine, Riskin’s book tries to rehabilitate the ignored Frenchman, arguing that Lamarck and Darwin were both right in some ways and wrong in others, with Lamarck making seminal contributions to biology.  But anybody who knows the history of evolutionary biology must realized Darwin was more right than Lamarck—by far—and it’s a stretch to even say that Lamarck made any big contributions to modern biology.

First here’s Levine’s short bio from Skeptic:

George Levine is the author of Darwin and the Novelists (Harvard University Press/Chicago University Press); Darwin Loves You (Princeton University Press); and Darwin the Writer (Oxford University Press). He was a longtime professor at Rutgers University until his retirement in 2006.

Let’s take Levin’s major points (and errors) one by one.

a.) Where Darwin and Lamarck were both right.

Both of them suggested that evolution occurred by naturalistic means.  But while Lamarck’s ideas never caught on, Darwin’s did: within a decade after he published On the Origin of Species in 1859, most biologists and many educated people embraced Darwin’s main theories (see below).

b.) Where Darwin and Lamarck were both wrong, and how they differed in wrongness.

Neither Darwin nor Lamarck understood how heredity worked, and both suggested that acquired changes could be inherited.  While Lamarck suggested that use of an organ of feature changed the physiology of an organism in a way that could be inherited, he didn’t specify how.  Unlike Lamarck, Darwin did not see the inheritance of acquired traits as the only or the overweening method of evolutionary change, though he did posit a mechanism: organs and other bodily parts transmitted their changes to the reproductive organs through the production of small “gemmules” that somehow made their way to the reproductive organs. Darwin’s theory is called pangenesis, and was also wrong. The inheritance of acquired traits as a means of adaptive change has been disproven by many experiments. As I’ve written in detail, epigenetic modification of the DNA by environmental change is not a mechanism of adaptive evolution.

Although both men were wrong about acquired traits changing inheritance for good, Lamarck was also wrong by positing a teleological process that, over time, drove species to become more complex.

c.) Why Darwin is revered and Lamarck ignored.

While Levine spends a lot of time arguing that Lamarck and Darwin were both wrong, and yet both made seminal contributions to biology, he largely ignores the reason why Darwin is lauded and Lamarck is ignored   There are two reasons for this:

1.) Darwin provided copious evidence for evolution and against creationism, and Lamarck did not. If you read The Origin, you will find chapter after chapter detailing evidence for why evolution was correct and Biblical creationism was not.  Darwin describes how features of development, vestigial organs, biogeography, and even the fossil record (very sketchy in Darwin’s time) militate against creationism and in favor of evolution. In this way, Darwin shoved aside the dominant theory of how life came to be in favor of a naturalistic theory driven by what he saw as his greatest idea, #2:

2.) Darwin was the first to suggest a plausible mechanism for evolution supported by evidence: natural selection. Lamarck’s mechanism was not plausible. The idea of natural selection is the theory that organisms with traits that made them more adapted to the environment left more offspring—and, if trait variation was heritable (as it usually is), enriched the next generation with more adaptations—was Darwin’s greatest contribution to biology. While the idea of evolution was “in the air” in the mid-19th century, if Darwin hadn’t come up with natural selection, the modern theory of evolution would have been delayed by decades.  Although Darwin did see “pangenesis” as one mechanism of evolution, another was the (correct) idea that individuals in a species were different from another and those differences were largely due to differences in their hereditary material.  Darwin proposed that these differences could be due to “mutations” coming from environmental changes. Though that wasn’t correct (mutations appear to be random), environmental causation isn’t necessary for natural selection to work. All we need to know is that something causes individuals to differ in their traits, and some of those differences could be inherited. That, combined with the idea that trait differences could affect reproduction, is all ye need to know.

Darwin supported this idea simply by drawing a parallel with artificial selection, which, as Darwin’s own experiments with pigeons showed, was hugely successful in modifying species in any direction the breeder wanted.  The importance of this argument is shown by Darwin’s devoting the first chapter of The Origin to it: “Variation Under Domestication.” My favorite quote in this chapter is this:

Breeders habitually speak of an animals’ organisation as something quite plastic, which they can model almost as they please.”

It works for plants, too, of course, as we know from almost all our domestic crops being extreme modifications of species found in nature, all effected by artificial selection.

The parallel is nearly exact, save that the breeder determines which traits are adaptive, while it happens by itself in nature. But in both cases more-adapted individuals leave more offspring, transforming the species. The argument is very convincing, and natural selection transforming species has now been demonstrated many times in nature. You don’t need a human breeder.

Darwin, then, is most revered for the twin achievements of demonstrating the truth of evolution and then providing a plausible mechanism for the production of “the endless forms most beautiful and most wonderful” limned in the last paragraph of The Origin. Lamarck did neither of these things.

d.) So what were Lamarch’s contributions to modern biology?  Levine mentions three.  “Lamarck was the first to use the word ‘biology’ and to conceive biology as a separate science.” And he “invented the category ‘vertebrates’, separating them off from ‘invertebrates’ in scientific study.” That’s about it, and it doesn’t even come close to what Darwin accomplished.  Besides, in many cases it’s not useful to separate vertebrates from invertebrates. Often we want to study phenomena seen in both groups.

e.) Levine’s  review has a lot of misconceptions about Lamarck.  For some reason that baffles me, Levine thinks that Lamarck contributed to modern biology the idea that, via their own behaviors, organisms can change how natural selection acts on them.  Lamarck, he said, added to modern biology the idea that agents are not just passive “victims” of natural selection imposed from without by the environment, but can promote their own evolution through their behavior.  Beavers, for example, evolved to build dams, and by evolving that behavior they made themselves subject to whole new areas of natural selection: finding the right places to build, developing sharper teeth and behaviors to gnaw down trees, and turning their dams into homes.

But that idea—that organisms can promote their further evolution through behavior—while correct, was not contributed by Lamarck. It’s a well-established part of the modern theory of evolution called niche construction. It was implied even by Darwin, who wrote in his book on earthworms that they modify their environments. But it was brought into evolutionary biology by my own advisor, Dick Lewontin, and then made more formal by John Odling-Smee and Mark Feldman.  Lamarck had nothing to do with this addition to the modern synthetic theory of evolution.

In fact, Levine goes even further, and jumps the rails when he seems to suggest that organisms want to evolve in certain directions, a view that borders on Lamarck’s teleology. (Bolding is mine,)

Natural selection and Lamarckian evolution are not necessarily incompatible theories. Riskin points out that in 1896, James Mark Baldwin published a paper called “Organic Selection,” which, after first being contested ferociously “had recently achieved widespread acceptance among biologists.” “Organic Selection means selection that an organism enacts upon itself by behaving in certain ways.” For example, once humans found that opposable thumbs could help in survival, natural selection did its work and those born with opposable thumbs had a greater chance to survive. In this case, natural selection and something like Lamarckian intention co-exist. In fact, they depend upon each other. Human desire and intention change what it is to adapt. So, as Riskin puts it, “organisms aren’t just the passive objects of natural selection but its active conductors.” Hey, that might be a way to make Lamarck’s poor abused giraffes respectable.

For Lamarck, via Riskin, organisms are active in their own adaptiveness. They are capable of changing the environment to make it compatible with their needs. And here Riskin introduced me to a powerful and crucial element of Lamarckism that we have all ignored to our peril: Organisms are capable of changing their own environments. Usually, they do it in what they take to be their own interest. As we have all too slowly become aware, we have been working toward a new era: after the Pleistocene has come the Holocene and now (though still disputed) the Anthropocene—the era “defined by significant human impact on Earth’s geology, climate, and ecosystems.”

How can we hack our way through this weedy patch of misunderstanding? First, how did humans get opposable thumbs in the first place, if not through natural selection? Did a hominim with a mutant thumb appear one day, observe it had opposable thumbs, and then say, “I must evolve in this way.” That sounds dumb, but here Levine has got the cause and effect reversed. Natural selection did its work on the ancestral hominin hand to form opposable thumbs which, as time passed, became stronger and more dextrous (we know this from the fossil record).  What does “intention” have to do with this? Nothing, as far as I can see. Nor can organisms evolve via “what they take to be their own interest.”  Natural selection has nothing to do with the “self interest’ of organisms, most of which don’t even have “self-interest”.  Yes, organisms can behave in ways that suit them, and that can lead to new selective pressures, as with beavers and earthworms, but “interest’ has nothing to do with it.  This idea borders on teleological, as it is in the wacky new “Third Way” of evolution, which also has teleological elements,

f.) As if this weren’t bad enough, Levine tars the modern theory of evolution by connecting it with eugenics and environmental despoliation. It’s another way of praising Lamarck because his theory wasn’t in any way connected with this bad stuff.  Levine says this:

One depressing and horrifying fact of which Riskin has made me aware is that just about every major figure in the development of the “modern synthesis” was a eugenicist. Clearly, this is no accident. Humans, from the perspective behind the Weismann barrier, are objects to be manipulated, coal mines to be dug out. Bad gene clusters to be eliminated. It is partly as a polemic against this view of the absence of agency in this world that Riskin devotes the later part of her book. But it never takes the shape of polemic.

. . . What Riskin shows is that for Lamarck the kind of thinking implicit in the modern synthesis was and remains a moral and physical disaster.

It’s a physical disaster presumably because Lamarck pointed out that humans were destroying the environment and Darwin didn’t. But again, this has nothing to do with Darwin’s theory, nor does it show that Darwin was “wrong. ”  Connecting Darwinism with eugenics and environmental depredation is the final error in a string of misconceptions and outright errors by Levine. Pity that this stuff was published in Skeptic magazine, which apparently didn’t get Levine’s review vetted by an evolutionary biologist. I emphasize again that because I haven’t read Riskin’s book, my criticisms are directed not at her but at the reviewer.