Category: evolution-bashing

Once again: A misguided article on why the theory of evolution is obsolete

June 29, 2022 • 11:00 am

This article in the Guardian really says nothing new beyond what a dozen articles have said already: “There are things we know about evolution that Darwin never imagined, and we’ve made many discoveries that weren’t part of the ‘modern synthetic theory of evolution’ forged in the Thirties and Forties.”  I’ve posted a ton about these issues already, many of which are said to form an “Extended Evolutionary Synthesis”, or EES. It turns out that yes, things like the neutral theory and epigenetics weren’t imagined by Darwin, who knew nothing about heredity, or even by the great Theodosius Dobzhansky, but the exponents of the EES sometimes try to pretend that it’s more than an extension of evolutionary biology, but a Kuhnian “revolution” mandating a “new theory of evolution”. Indeed that’s what the article below maintains. (The answer to the headline question is “yes.”)

But in fact we do not need a new theory of evolution: the basic theory proposed by Darwin in 1859, which includes gradualism, variation, natural selection as a critical factor responsible for adaptation, splitting of lineages, and the resultant common ancestry of all species and individuals, still holds. But we know a lot more now, and most of it can easily be incorporated into evolutionary biology. In fact, if you look at evolution textbooks from a few years ago, you’ll find phenomena like epigenesis, the neutral theory, “niche construction”, plasticity, and the like not only discussed, but shown to have been part of discussions about evolution for half a century or more. Now they’re simply part of “evolutionary biology”, which, yes, has expanded, but not in a manner that mandates replacing the old theory. Like cosmology, we just add new stuff to the field as it turns up, and ditch the stuff that turns out to be wrong.

Yet the author, Stephen Buranyi, a Guardian science writer, cannot help himself from not only distorting the history of evolutionary biology, but arguing that evolutionary biology needs a thorough rehaul (It doesn’t, for it’s not like “Darwin was totally wrong!”) And Buranyi takes great delight in couching the scientific debate about the importance of various factors in organismal evolution as “a culture war.” That’s nuts, it’s just a normal debate in science, and the outcome hinges on facts, not ideology.

Click to read the piece.

There’s simply too much to criticize and correct here, so I’ll take just five of Buranyi’s misguided claims.

a.) We don’t understand how important evolutionary features developed, like the eye. It’s true that we don’t know the exact sequence in which some complex adaptations developed, and we won’t because we weren’t there. But we do know from the fossil record about how whales evolved from terrestrial hoofed ungulates over about 10 million years, and we have the fossils to show it. Ditto for many other evolutionary transitions, like from fish to amphibians. But by using the eye, Buranyi resurrects the old (and refuted) creationist criticism that “how could an eye possibly evolve in a stepwise fashion from a simple light-sensitive spot?” The implication is that our ignorance of how this actually happened means that something’s seriously wrong with evolutionary theory.

Actually, this problem was first considered (and in principle solved) by Darwin, and discussed more extensively by Richard Dawkins in several places (e.g., here). No, we don’t know exactly how and when it happened, but eyes evolved independently several times, and we have a plausible sequence about how one can go, via an evolutionary sequence of small adaptive steps, from a light-sensitive eyespot to the complex “camera eye” of vertebrates and cephalopods. And, using estimates of parameters, we can show that there was plenty of time for this to happen via selection. If we can do that, with each step being adaptive (and in fact, actually seen in species living today), then the evolution of the eye is not a difficulty for simple Darwinism.

In fact, in 1994 Nilsson and Pelger published a paper showing that, with conservative assumptions about mutation rates and selection, you could model the evolution of a camera eye from a light-sensitive spot in a few hundred thousand years. If you want a precis, read Dawkins’s Nature article about the paper: “The eye in a twinkling.”

I discuss this in a bit of detail because Buranyi cites the eye as one of our insuperable evolutionary problems:

You may recall the gist from school biology lessons. If a creature with poor eyesight happens to produce offspring with slightly better eyesight, thanks to random mutations, then that tiny bit more vision gives them more chance of survival. The longer they survive, the more chance they have to reproduce and pass on the genes that equipped them with slightly better eyesight. Some of their offspring might, in turn, have better eyesight than their parents, making it likelier that they, too, will reproduce. And so on. Generation by generation, over unfathomably long periods of time, tiny advantages add up. Eventually, after a few hundred million years, you have creatures who can see as well as humans, or cats, or owls.

This is the basic story of evolution, as recounted in countless textbooks and pop-science bestsellers. The problem, according to a growing number of scientists, is that it is absurdly crude and misleading.

For one thing, it starts midway through the story, taking for granted the existence of light-sensitive cells, lenses and irises, without explaining where they came from in the first place. Nor does it adequately explain how such delicate and easily disrupted components meshed together to form a single organ. And it isn’t just eyes that the traditional theory struggles with. “The first eye, the first wing, the first placenta. How they emerge. Explaining these is the foundational motivation of evolutionary biology,” says Armin Moczek, a biologist at Indiana University. “And yet, we still do not have a good answer. This classic idea of gradual change, one happy accident at a time, has so far fallen flat.”

Both Buranyi and Moczek are dead wrong. We know about light-sensitive pigments, and we know they exist in microorganisms that can use them to detect the presence of light, which is itself adaptive.  The meshing of the various components has been modeled, and we can see every posited step in the process instantiated as an adaptation in one or more living species. What we don’t know is when and in which order things happened. Nevertheless, we see a plausible order in nature and we can model the process without difficulty. To say that “the classical idea of gradual change has fallen flat” is just (pardon my Spanish) caca de vaca. Does Buranyi think the eye appeared as a single “macromutation”? (More on that issue later.) So his distortions of history—he doesn’t mention, for instance, the paper of Nilsson and Pelger—begin at the article’s outset.

b.) Plasticity is a profound evolutionary problem that was neglected by evolutionary biology. Plasticity refers to the ability of an organism’s genome to respond to different environments in different ways (usually adaptive), either permanently or reversibly. We get tans when there’s too much sun, and this protects us from UV damage. Many mammals grow long hair in the winter and lose it in the summer.  Arctic mammals can turn white in the winter and brown in the summer as a means of camouflage. Rotifers and other small organisms grow fish-deterring spines if they develop in water containing fish, and plants can alter their form depending on where they’re growing.

We’ve known this for decades, so the evolution of plasticity is not something that’s stumped evolutionists. It’s easy to envision a genome that can respond to different environments in different ways. (One fantastic example is how the same genome can produce a caterpilllar and then a butterfly depending on the environment and time of development.) All that’s required for plasticity to evolve is that there be reasonable chances that an organism can find itself in different environments, i.e., a decent probability that you’d find yourself in environments, A, B, C, or so on.  Wild cats that live in environments that go from hot to cold over the year (or over altitude), would have greater reproduction if they had genes that could induce hair growth when the weather is cold and hair loss when it gets warmer. For arctic hares, the probability that the environment will be white in winter and green/brown in summer is 100%, but the probability that we’ll be out in the sun enough to get a tan is lower than 100%. But it doesn’t have to be 100% if enough people are out in the hot sun and could get melanoma. That’s enough to keep the tanning response encoded in our genome.

Indeed, plasticity can even reveal genetic variation that can be subject to selection; this idea of “genetic assimilation” was discussed and demonstrated eighty years ago.

Yet Buranyi sees plasticity as another startling non-Darwinian, mysterious, and neglected phenomenon. He’s wrong, though he gives some cool examples of plasticity. His words (my bolding):

One of the most fascinating recent areas of research is known as plasticity, which has shown that some organisms have the potential to adapt more rapidly and more radically than was once thought. Descriptions of plasticity are startling, bringing to mind the kinds of wild transformations you might expect to find in comic books and science fiction movies.

. . . Plasticity doesn’t invalidate the idea of gradual change through selection of small changes, but it offers another evolutionary system with its own logic working in concert. To some researchers, it may even hold the answers to the vexed question of biological novelties: the first eye, the first wing. “Plasticity is perhaps what sparks the rudimentary form of a novel trait,” says Pfennig. [JAC: Pfennig is just guessing here.]

Plasticity is well accepted in developmental biology, and the pioneering theorist Mary Jane West-Eberhard began making the case that it was a core evolutionary force in the early 00s. And yet, to biologists in many other fields, it is virtually unknown. Undergraduates beginning their education are unlikely to hear anything about it, and it has still to make much mark in popular science writing.

What is the new “logic” involved in plasticity? The evolution of plasticity, like the examples Buranyi gives, simply follows the logic of natural selection acting when there are environmental conditions or changes that can be encountered with some frequency. In such a case it pays for your genome to evolve flexible adaptive responses to different environments.

As for the claim that students aren’t exposed to this, well, it’s sure in the evolution textbooks. I just pulled Doug Futuyma’s 1998 (third edition) textbook Evolutionary Biology off my shelf (it’s the one I used when I taught introductory evolution), and, sure enough, there’s a whole section on plasticity and “norms of reaction”, as they used to be known. (A norm of reaction is simply when a given genome can respond to different environments by producing different phenotypes.) Doug’s book was published nearly 25 years ago, and the phenomenon was discussed at length by others long before that.

c.) Biologists have unduly neglected macromutationism: the idea that a complex feature can come into being in a single step.  This was indeed a discussion in the 1930s and 1940s, with scientists like Richard Goldschmidt proposing a “hopeful monster” hypothesis: that major evolutionary features could come into being via a single mutation that affected many systems at once. To Goldschmidt and his followers, “mutationism” was considered an alternative to natural selection.  Ernst Mayr once told me that he heard Goldschmidt make this remark: “I firmly believe that the first creature considered a bird hatched from an egg laid by a creature considered a reptile.” (That implies a huge step rather than a gradualistic evolution of reptiles into birds.)

Macromutationism, though briefly revived by Steve Gould as part of “punctuated equilibrium” (see below), eventually lost plausibility for several reasons. First, it’s unlikely that a mutation could occur that would create a complex feature (or a new group, like birds) in one step, for there’s a very low probability that a coordinated and cooperative set of features could arise in one step. In fact, although we can see big “homeotic” mutations in the lab (like an eye developing on a wing, or a leg as part of an insect mouth), these are developmental anomalies that are maladaptive. More important, genetic dissection of even minor phenotypic changes that have occurred in nature, like the shape of insect genitalia, have repeatedly shown them to be based on several mutations of small effect. We have virtually no evidence for mutations of large effect being important in evolution.

Of course, even macromutations have to obey the rules of population genetics, so even if one occurred, it could not spread through a species without natural selection to drive it. That means, of course, that “mutationsm” is not an alternative to selection!

Finally, we have the data. The fossil record documenting major changes, like the evolution of birds, whales, amphibians, hominins and the like, show no such “macromutations”: we see a gradual change in phenotype from ancestor to descendant with different traits showing up at different times. Of course mutations do vary in size, but I can’t point to a single adaptation in nature that requires us to postulate macromutations because the feature supposedly can’t be produced by a stepwise accumulation of smaller mutations. (This latter claim, by the way, is promulgated by IDers like Behe, who posit God instead of macromutations to bridge the gap.)

Yet Buranyi implies that macromutation, which died after a spirited scientific debate, is unduly neglected (my emphasis):

Even more ominous for Darwinists was the emergence of the “mutationists” in the 1910s, a school of geneticists whose star exponent, Thomas Hunt Morgan, showed that by breeding millions of fruit flies – and sometimes spiking their food with the radioactive element radium – he could produce mutated traits, such as new eye colours or additional limbs. These were not the tiny random variations on which Darwin’s theory was built, but sudden, dramatic changes. And these mutations, it turned out, were heritable. The mutationists believed that they had identified life’s true creative force. Sure, natural selection helped to remove unsuitable changes, but it was simply a humdrum editor for the flamboyant poetry of mutation. “Natura non facit saltum,” Darwin had once written: “Nature does not make jumps.” The mutationists begged to differ.

These disputes over evolution had the weight of a theological schism. At stake were the forces governing all creation. For Darwinists especially, their theory was all-or-nothing. If another force, apart from natural selection, could also explain the differences we see between living things, Darwin wrote in On the Origin of Species, his whole theory of life would “utterly break down”. If the mutationists were right, instead of a single force governing all biological change, scientists would have to dig deep into the logic of mutation. Did it work differently on legs and lungs? Did mutations in frogs work differently to mutations in owls or elephants?

. . . The modern synthesis was such a seismic event that even its flatly wrong ideas took up to half a century to correct. The mutationists were so thoroughly buried that even after decades of proof that mutation was, in fact, a key part of evolution, their ideas were still regarded with suspicion. As recently as 1990, one of the most influential university evolution textbooks could claim that “the role of new mutations is not of immediate significance” – something that very few scientists then, or now, actually believe. Wars of ideas are not won with ideas alone.

This gets everything wrong. It misses the evidence against “mutationism” and implies that “mutationists” simply emphasized that mutations are an important part of evolution—something that NOBODY DENIES. In fact, mutationists implied not only that mutations of very large effect are pivotal in evolution, but drive evolution without the need for natural selection. As we all know, mutation and selection are both important for adaptive evolution: mutations are the gas and evolution is the car. You can’t say that one is more important than the other. By giving a misleading account the history of biology here, and conflating “mutationism” with “the importance of mutations in evolution,” Buranyi has done the reader a huge disservice.

d.) Punctuated equilibrium was only about the pace and timing of evolutionary change.

Other assaults on evolutionary orthodoxy followed. The influential palaeontologists Stephen Jay Gould and Niles Eldredge argued that the fossil record showed evolution often happened in short, concentrated bursts; it didn’t have to be slow and gradual.

In fact, the real critique of evolutionary orthodoxy in Gould and Eldredge’s theory of punctuated equilibrium was the linking of a jerky pattern in the fossil record to a novel and almost non-Darwinian process, involving macromutations, evolution in isolated populations, the crossing of adaptive valleys via strong genetic drift, and then sorting out the variable groups via “species selection” instead of conventional Darwinian “genic selection.” While I have envisioned one form of species selection that operates in nature (see the last chapter of my book Speciation with Allen Orr), that process operates on rates of speciation to which characters are linked, but is neither identical to nor as ubiquitous as the process Gould postulated.

The failure of the various parts of Gould’s theory to work (including adaptive valley crossing via drift) was demonstrated by a number of experiments and pieces of theoretical work (see here and here); I summarized the failure and demise of Gould’s mechanistic theory here. I’m not sure if the “jerky” fossil record that gave rise to the postulated processes is still accepted as ubiquitous by paleontologists, but as for now, the reasons Gould and Eldredge advanced for such a pattern—the important attack on neo-Darwinism—are incorrect. (There are of course several causes for “jerky” evolution, including an incomplete fossil record or a jerky process of natural selection itself.)

e.) The scientific debate about the ambit of evolutionary biology is a “culture war.”  This bit really got my knickers in a twist:

To release biology from the legacy of the modern synthesis, explains Massimo Pigliucci, a former professor of evolution at Stony Brook University in New York, you need a range of tactics to spark a reckoning: “Persuasion, students taking up these ideas, funding, professorial positions.” You need hearts as well as minds. During a Q&A with Pigliucci at a conference in 2017, one audience member commented that the disagreement between EES proponents and more conservative biologists sometimes looked more like a culture war than a scientific disagreement. According to one attender, “Pigliucci basically said: ‘Sure, it’s a culture war, and we’re going to win it,’ and half the room burst out cheering.”

Bad call, Massimo! No, it’s not a culture war, even if sometimes scientists get heated and use terms like “evolution by jerks” to characterize advocates of punctuated equilibrium. The debate was conducted, and largely settled, by scientific argument that didn’t include that kind of acrimony. It is simply a debate about what mechanisms are important in evolution. My own view is that yes, the Modern Evolutionary Synthesis includes stuff that we didn’t even dream of 80 years ago (the “neutral theory” is one), but there is simply no reason to pronounce neo-Darwinism obsolete. “Expansion” is an okay word, but saying that “we need a new theory of evolution” is both ignorant and hyperbolic.

I could write for several days on the errors and distortions of Buranyi’s piece, but I’m tired. What’s given above is meant to serve merely as a few examples of the misguided nature of his article. What’s worse is that it misleads laypeople into thinking that there’s something seriously wrong with modern evolutionary theory. That itself could hearten creationists, and I’m sure the IDers are already lapping up the Guardian piece.

I get (creationist) email

June 3, 2022 • 8:30 am

I don’t trash many comments at the outset unless they’re either obtuse, uncivil, overly religious, or creationist. This one falls in the last class.  Actually, there were two attempted comments from someone with the handle “See Noevo“; both were aimed at the thread after the post, “The intellectual vacuity of mathematical arguments against evolution.”  See was responding to an exchange with another commenter about Michael Behe.

See Noevo’s Comment #1: not posted.

My prediction is that one day evolution will be shown to ALL to be perhaps the greatest embarrassment and shame in the histories of science and of rational thought.

But I have to ask about
“An alternative approach is to flip all 100 coins, leave the ones that landed heads as they are, and then toss again only those that landed tails.”
I thought evolution was constant. Why is Mother Natural Selection keeping the heads as heads for, well, forever?

To explain: the metaphor was one way Jason Rosenhouse explained how a random process can be winnowed by a nonrandom process to produce the appearance of “design”. The randomness (mutational variation) was represented by the tossed coins, while the nonrandom process involves keeping the heads and re-tossing the tails.  Eventually you get to all heads, which is the analogy to an adapted organism.

My best interpretation of this comment is that “See Noevo” is pointing out out that evolution is always occurring, so the heads won’t be kept forever. Some of the coins will get turned over when evolution occurs over the long term. Ergo a seeming contradiction; ergo God Did It.

But DUH! We’re talking about the short-term build up of the appearance of design, not the fact that any one gene sequence will remain the same until the end of time. Nobody believes that.

At any rate, this evolution critic apparently doesn’t know what he/she/they are talking about, and I didn’t allow that ambiguous and obstreperous comment to appear.

But I did allow this comment to appear, and even answered it.

Here’s “See Noevo”‘s comment #2, posted:

In reply to whyevolutionistrue.

To whyevolutionistrue:

Do all first-time commenters have their post put into “awaiting moderation”?
How long should they expect to be in this state?

My response:

In your case, forever.

But he did get his say above. However, that’s the last thing he will post.  (I’ll assume “See Noevo” is a male.)

Brian Charlesworth on the errors of a new paper supposedly showing that a fundamental assumption of neo-Darwinian evolution is wrong

May 9, 2022 • 8:00 am

Intro by Jerry:  One of the pillars of neo-Darwinian evolution is the assumption, supported by a great deal of evidence, that mutation is “random.” This does not mean that mutations occur with equal frequency everywhere in the genome (they don’t), that different genes have the same mutation rate (they don’t), or that even within a gene some mutations don’t occur more often than others (they do). Rather, the statement that “mutation is random” means that the likelihood of a mutation occurring does not depend on whether in a given situation it would be advantageous or deleterious.

The idea that mutations are “nonrandom”—usually meaning that adaptive mutations are more likely to occur in some situations (e.g., a change in environment)—has been bruited about for years, mainly because if this was a fairly common phenomenon, it would create a substantial rethinking of the neo-Darwinian theory of evolution. But there is no way we know of that the frequency of an error in the DNA sequence, which is what a mutation is, can be elevated in the adaptive direction when the environment changes. (We know that environmental changes can raise the overall mutation rate, but this is not an adaptive phenomenon because the vast majority of mutations are harmful.) Because of this lack of evidence for “adaptive mutation,” and the absence of a mechanism whereby it could occur, evolutionists continue to accept that mutations are “random” in the sense I defined.

Recently, a paper appeared that seemed to show that at least one mutation in human hemoglobin—the one causing sickle-cell anemia when present in two copies—could occur more frequently in areas where the mutation is adaptive: malaria-ridden areas of Africa. The sickle-cell mutation, as Brian Charlesworth shows below, is adaptive, but only when present in one copy, when, together in a “heterozygote” with one copy of the “normal” hemoglobin beta chain, it confers substantial protection against malaria.  The heterozygote has higher survival and reproductive fitness than either the homozygote for the ‘normal’ allele, which is more prone to fatal malaria, and the sickle-cell homozygote, which has the disease sickle-cell anemia and is prone to die before adulthood.  The mechanics of population genetics show that if a heterozygote with one copy of each of two alleles has higher reproductive ability (read “survivorship” here) than either of the two homozygotes, it will be maintained in the population at a stable equilibrium frequency, regardless of how bad off the homozygotes are. The sufferings of those with sickle-cell anemia can be seen as the price paid because of the higher malaria resistance of heterozygotes carrying only one copy of the gene. It also shows that evolution doesn’t create the optimum situation: that would be a single mutation that causes malaria resistance when present in either one or two copies.

This, by the way, explains why African-Americans are more prone to sickle-cell anemia than people from other populations, for they still carry the “HbS” mutation prevalent in their ancestors who were brought to America as slaves. The frequency of the HbS mutation in the U.S., however, is now falling, and for two reasons: we don’t have malaria in the U.S., which is necessary to keep the gene at an equilibrium frequency, and because African-Americans have intermarried with whites, who don’t carry copies of HbS.  Eventually, prenatal testing and genetic counseling will be able to eliminate sickle-cell anemia, and the HbS allele, completely.

At any rate, the paper, by Melamed et al. (reference below), appeared to show that the mutation rate from the “normal” DNA sequence to the HbS “sickle-cell” sequence was higher in Africans than in Europeans. This was quickly picked up by the popular press as an example of “adaptive mutation” and as a refutation of modern evolutionary theory. (The “Darwin Was Wrong” trope still sells newspapers, especially in America!) Many readers wrote me and asked me about this paper, which I hadn’t yet read, but I told them that a better analysis was in the works.

I pointed this out to my friend, colleague, and ex-chairman (at Chicago) Brian Charlesworth, one of the world’s premier evolutionary geneticists. He quickly spotted the error in the Melamed et al. paper that refuted its conclusion of “adaptive mutation,” but was too busy to refute it on paper. After I kept hectoring him to write something up since the “Darwin was wrong” trope was associated with this paper in many articles in the popular press, he finally deigned to write a short and sweet refutation. Rather than submit it as a rebuttal to the journal (he said he has two refutations of other papers in press, and doesn’t want to get a reputation as a debunker), Brian allowed me to publish the rebuttal here. I’ve put it between the lines below.

Note that the error in Melamed et al. stems from a flaw in the assumptions: that all the new mutations analyzed were independent.

No evidence for an unusually high mutation rate to an adaptive variant

Brian Charlesworth
Institute of Evolutionary Biology
School of Biological Sciences
The University of Edinburgh
Edinburgh, UK

The hemoglobin S variant (HbS) causes the near-lethal sickle cell disease when homozygous (present on both the maternal and paternal chromosomes) and confers protection against malaria when heterozygous (present on either the maternal or paternal chromosome). The HbS variant exists at substantial frequencies in several populations in Africa, as well as in Arabia and India. It is the classic example of heterozygote advantage, whereby a mutation that increases the fitness of its heterozygous carriers cannot replace its alternative because of the loss of fitness to homozygotes. (Note that 2022 is the 100th anniversary of R.A. Fisher’s discovery of how this process works). The HbS mutation is a single change from adenine to thymine at the sixth amino acid position in the beta globin gene, resulting a change in the amino-acid in the corresponding protein for valine to glutamic acid (it was the first mutation to be identified as causing a change in the sequence of a protein). Studies of the DNA sequences of chromosomes carrying the HbS mutation show that there are five major classes of sequences associated with it, but recent analyses show that the mutation probably arose only once, followed by recombination events that placed it onto different genetic backgrounds. This provides a classic example of what is known as a “partial selective sweep”, in which a new mutation with a selective advantage arises on a single genetic background, so that variants present on this background spread through the population in association with it.

Melamed et al. (2021) claim to have evidence that challenges the standard neo-Darwinian view that natural selection acts on mutations that arise “randomly”, i.e., without reference to their effects on the survival or fertility of their carriers (indeed, most mutations with noticeable effects reduce the fitness of their carriers). The evidence for Melamed et al.’s claim comes from an experiment in which the authors applied a novel technique for identifying new mutations in millions of sperm cells. With regard to the detection of HbS mutations, they characterized sperm from 7 African and 4 European men. They observed 9 instances of the HbS mutation in the sperm of Africans and none in the Europeans. They pointed out that HbS is at a selective advantage in Africans but not in Europeans, and suggested that the seemingly higher mutation rate is the result of a hypothetical process proposed by Adia Livnat, a co-author of the paper, whereby “adaptations and mutation-specific rates jointly evolve”. This claim has been disseminated in the media as evidence against the neo-Darwinian view of selection on random mutations [JAC: see below for some of these media references]– here it is claimed that mutations that are selectively advantageous in a particular environment arise more frequently than in environments where they lack an advantage.

However, there is no statistical support for the claim that there is a higher mutation rate to HbS in African men. While the authors looked at very large number of sperm, these came from only 11 individuals. Five of the nine HbS mutations occurred in a single individual, and 2 other individuals contributed 2 mutations each. The events within individuals cannot be treated as independent of each other, because there is a large population of dividing cells that are precursors of the mature sperm. If a mutation occurs in a cell that gives rise to several sperm after a number of divisions, there will be several copies of the mutation in the sperm pool. This is the cause of the well-established fact that the frequencies of mutations in human sperm increase with the man’s age. If we treat each individual as a single observation, we have 3 cases of HbS mutations among 7 Africans and 0 among 4 Europeans. Fisher’s exact test shows that the difference between Africans and Europeans has a probability of about 11% of arising by chance in the absence of any true difference.

There are other reasons for doubting this claim. First, it is exceedingly hard to see how there could be any biological process that could cause the HbS mutation to have a higher mutation rate in order to allow Africans to evolve malaria resistance, which is thought to have become a significant selective factor at most around 20,000 years ago. Mutations arise as errors in the replication of DNA molecules or as the result of damage to non-replicating molecules. There is no known mechanism whereby an organism could devise a process that would allow it to produce one specific class of mutation at a higher-than-average frequency just when that mutation is at an advantage. Further, the genetic evidence referred to above suggests that the HbS variant prevalent in human populations traces its ancestry back to a single ancestral mutation (Shriner and Rotimi, 2018; Laval et al., 2019) , so that there is no reason to believe that a high mutation rate has enabled multiple copies of the mutation to spread.

References

D. Melamed et al. 2022. De novo mutation rates at the single-mutation resolution in a human HBB gene region associated with adaptation and genetic disease. Genome Research 32:1-11.  Free pdf here. 

D. Shriner and C. N. Rotimi. 2018. Whole-genome-sequence-based haplotypes reveal single origin of the sickle allele during the Holocene wet phase. Am. J. Hum. Genet. 102:547-556.

G. Laval et al. 2019. Recent adaptive acquisition by African rainforest hunter-gatherers of the late Pleistocene sickle-cell mutation suggests past differences in malaria exposure.  Am. J. Hum. Genet. 104:553-561.

Among the many popular articles that cite Melamed et al. as a rebuttal of modern evolutionary theory, see here, here, here, here, here, ad infinitum:

Two examples (click on screenshot)s:

 

And here’s Brian:

 

Once again, Darwin gets dragged into the muck by the Woke

January 8, 2022 • 11:00 am

Do you want uplifting news or depressing news? I have both. In the interests of having your day improve later, I’ll proffer the depressing news first. That news involves further attempts to drag Darwin down into the mud.

Dan Dennett called Darwin’s theory of evolution by natural selection a “dangerous idea” because it was like a corrosive acid that ate through and destroyed all ideas of design and a designer as explanations of nature and the way we think about it. Howard University biologist Rui Diogo, however, has a different take. Darwin’s views are “dangerous” because, apparently, they are sexist and racist. And, he adds, this tarnishes his theories and his legacy.

Now I’ve explained in detail, as have others, that yes, Darwin was a man of his time and emitted views that would be considered racist today, though he was ambiguous about even that, as you can see from reading The Voyage of the Beagle (this is part of my Antarctica talk on Darwin and the Fuegians). But there is no doubt that Darwin was far more of an abolitionist than most Brits of his time: his family (the Wedgewoods) had been opposed to slavery since the late 18th century, and Darwin never wavered on his dislike of slavery and support of abolitionism.

So we already know that Darwin wasn’t perfect by modern lights, but he was a damn sight better than most of his peers. I always ask people who like Diogo who tar Darwin with the label of “racist” or “misogynist” if they would have held fully modern and progressive views in the mid 19th century. I doubt it.

Yet the Pecksniffs insist on bringing up Darwin’s racism over and over again, as if we and the public haven’t heard enough about it.  And it’s not just brought up to fill in a historical gap about the man’s views—for we already know that—but to cast aspersions on Darwin’s legacy in biology.

Case in point: the topic of the upcoming lecture noted below. Speaker Rui Diogo‘s talk is billed as “an unflinching look at how the racism and sexism of the Victorian era undermined Darwin’s scientific work and legacy.” (My bold.)  There will be no flinching by Diogo, but there shouldn’t be by anyone.

First, what he’ll say is already well known by evolutionary biologists, historians of science, and any of the public who care to look up Darwin’s views.

More important, Diogo is dead wrong in asserting that Darwin’s biased views “undermine his scientific work and legacy.” Perhaps in Diogo’s eyes, but not in the eyes of most others. Are we supposed to think less of the theory of evolution, or of natural selection, or of Darwin himself, because he held views more liberal than those of his peers, but not up to snuff in the eyes of a Progressive Democrat? The goal of Diogo, it seems, is to tarnish the luster of Darwin. He won’t succeed because, in the main, Darwin got his science right.

But nobody’s perfect, and I highly doubt that if Diogo was an upper-class Englishman in the Victorian era, he’d be waving signs saying “Black Lives Matter.”

If you want to pay $30 to hear this nonsense, be my guest. But remember that this is sponsored by the Smithsonian Institution. Click on the screenshot if you want to be fleeced.

x

UPDATE: I’ve found that Dr. Diogo seems to be dining out on Darwin. To see a related lecture from last fall, click on the screenshot:

I can’t be arsed to rebut the following summary of this lecture, as probably written by Diogo. Let me just say that yes, there were precursors of Darwin’s ideas before The Origin, including even natural selection by Patrick Mathew. But his greatness was cobbling together a magnificent edifice that has, in the main, stood the test of time. The bolding is mine:

Profs and Pints presents: “The Damage Done by Darwin,” a look at how the acclaimed naturalist’s racism and sexism undermined his work and haunts us to this day, with Rui Diogo, associate professor of anatomy at Howard University’s College of Medicine and resource faculty member at George Washington University’s Center for the Advanced Study of Hominid Paleobiology.

[Under current District of Columbia regulations attendees will be required to wear a mask except while eating or drinking. The Bier Baron will be requiring proof of Covid-19 vaccination or a negative Covid-19 test from the previous 72 hours for entry. It also will be requiring ticketed event attendees to purchase a minimum of two items, which can be food or beverages, including soft drinks.]

Charles Darwin has long been put on a pedestal and idolized as an objective, rational thinker who challenged the theist views of this day and changed how we see the world for the better. The truth, however, is a lot more complicated. Many of Darwin’s ideas were less original than widely believed and, in many cases, repackaged the false assumptions and prejudices of his era as the purported product of scientific observation. They helped buttress racist and sexist worldviews in ways that would do tremendous damage even to this day.

Tremendous damage? HOW? We already know that Hitler was not a Darwinian, so where’s all that harm? Answer: Diogo is making it up.

If others misused Darwin’s ideas to perpetrate bigotry, that’s not Darwin’s fault. But wait! There’s more!

Join Rui Diogo, an evolutionary biologist who has extensively reviewed Darwin’s books, diaries, notebooks, and letters, for an unflinching examination of Darwin’s life, thinking, and impact.

Professor Diogo will look at how almost none of the grand ideas attributed to Darwin—including the theory of natural selection—truly originated with him. He’ll discuss how Darwin stated as “fact” inaccurate constructions based on Victorian biases and stereotypes. And he’ll explore how Darwin’s assertions, and their warm reception, were very much a reflection of a broader ideological war that had left England’s wealthy Victorian elite eager to find new justifications for their relative privilege in the face of feared revolution.

Many scientists involved in similar research during Darwin’s time were not nearly as racist or sexist in their thinking. But Darwin was more skilled than most in packaging his ideas in ways that made them accessible and appealing to the general public. As a result, his writings became easy ammunition for generations of colonialists, white supremacists, and others seeking to defend social hierarchies, discrimination, and oppression.

Here is a man who doesn’t understand what Darwin actually accomplished.

h/t: Anthony

Faculty response to Western Washington University’s proposal to cancel the name of T. H. Huxley

August 20, 2021 • 11:30 am

As I reported on August 9, Western Washington University (WWU) is poised to change the name of its well known Huxley College of the Environment, named after “Darwin’s Bulldog” Thomas Henry Huxley and listed as one of the University’s “notable degree programs“. The reason? It’s the usual, detailed in a committee-produced document residing on the website of WWU’s President. One quote:

Even though Thomas Huxley made significant contributions in the field of biology [JAC: none are given], he also had significant contributions to scientific racism. He was a polygenist: someone who is of the belief that all races evolved from different origins instead of coming from one homosapien [sic]. This is not only scientifically disproven, but also a racist mindset, and an argument that one of his “archrivals” at the time called Richard Owen attempted to refute with evidence that we all are the same species that evolved from the same homosapien [sic] thousands of years ago. Huxley won the argument, and it is historian Nicolaas Rupke’s thesis that this argument between Huxley and Owen in which Huxley’s “deeply racist, polygenist viewpoint” won lead to building the scientific racism of the early 20th century.

Huxley’s supposed racism is said to cause “harm” to people, both in furthering racism and making students at Huxley College and WWU uncomfortable—in fact, causing them “harm.” The latter claim is simply ludicrous, while the former misguided.

There’s other bad stuff Huxley’s said to have done or said as well, but all of it, without exception, is either wrong or grossly exaggerated. If you know anything about Huxley, you’ll recognize that painting him as a racist who contributed to the discipline of eugenics which then was implemented in humans is risible. Further, his positive contributions to both science and society were completely neglected in the document, which was produced by people who had no expertise in nineteenth century England or Huxley in particular.

Now, eight academics from the Huxley College, trying to set the record straight, have produced a response to WWU’s proposal (the name of Huxley College is only one of several up for cancellation), and it’s pretty telling. I suggest you read it to see how distorted the original proposal for cancellation was.  It made several blatant errors, is rife with false and exaggerated claims, and draws largely on material produced by young-earth creationists who want to attack evolution by cancelling a school named after evolution’s most famous early defender.

You can see the document by clicking on the link below:

 

A few quotes to give you the tenor of the defense:

Natural Racial and Gender Inequality

Regarding the first claim, that Huxley held views of natural racial and gender inequality, we strongly encourage the Board of Trustees to reread the views of the historians, included in Appendix C. The LRTF’s summary is simply not an accurate reflection of their views, Rupke excepted. The concluding words of Paul White, one of those distinguished historians, presents a more accurate synthesis of those views:

Huxley is described as an abolitionist, he was in fact much more than this. He called for the elimination of all political, legal, and economic prejudices, equal rights and opportunities for people of all races (and sexes). If the staff and students agree to remove Huxley’s name, they should at least do so with a better understanding of his views, and an appreciation for his place in the history of human emancipation and activism.

An extremely troubling aspect of the LRTF report is that it lifts quotes first mined by creationists to confirm the racism and sexism claims against Huxley, while ignoring Huxley’s writings and other evidence that disprove the claims. Additionally, the report relies on earlier writings of Huxley, but totally ignores the evolution of thought that led him to see the unity and equality in all humanity. To be sure, Huxley’s earlier views reflected the same Victorian-era prejudices and bigotry of his scientific and clerical peers. But the report ignores the fact that Huxley escaped these prejudices to adopt views expressive of full racial and gender equality.

I guess if you engage in Wrongthink, but then come to Righthink later, it’s already too late. You’re in perdition forever.

Another false claim of WWU, one that I attacked in my earlier post:

Human Hierarchy and Scientific Racism

As for the second and third claims, that Huxley promoted a hierarchy of humans and scientific racism, the LRTF again relies on the ideas of Lyndon LaRouche operative Paul Glumaz (but without citation) and Rupke to paint Huxley as a polygenist (someone who accepts the idea that the human “races” evolved from different origins) and as holding that there exists a greater difference among “the races of man” than that between “the lowest Man and the highest Ape.”

First, it is a complete fabrication to claim that Huxley was a polygenist. This is simply another gaslighting distortion that was uncritically accepted by the LRTF. The consensus view in the history of science literature is that Huxley opposed the theistic theory of monogenesis – the idea that humans descended from Adam and Eve. This does not make him a polygenist. What he did support was scientific monogenesis, or the “new monogenism” – that H. sapiens is a single species with a monophyletic (one population) origin followed by diversification through migration and geographic isolation. The “poly-” element to Huxley’s thinking explicitly relates to the diversification through migration and geographic isolation, not to human origin.

Huxley’s view is wholly consistent with current scientific consensus and follows current thinking based on DNA evidence. The claim that Huxley’s views were not monogenist demonstrates fundamental misrepresentation of his views, the basic tenets of evolution, and the seeds of disinformation planted by creationists. Huxley in fact wrote that polygenists “have as yet completely failed to adduce satisfactory positive proof of the specific diversity of mankind.”

And, to make a long report short, the WWU cancellation document completely ignores the many positive contributions Huxley made. He was a big reformer of education and spent much of his later life giving lectures on science to working people. But here’s from the new rebuttal document:

. . . the report utterly ignores the demonstrable benefit and good that Huxley did create in his life work. In reality, the whole thrust of Huxley’s career was to make science, and education, more inclusive. Paul White again:

Huxley devoted a great deal of his career to them in the field of education reform. He campaigned tirelessly for universal education, for the introduction of science and other modern subjects to schools and universities, for a true ‘liberal education’ as well as technical education for the working classes. In doing so, he opposed some of the most entrenched ideological and institutional hierarchies in Britain at the time, those of class.

The LRTF report completely overlooks the concrete evidence of positive impact Huxley made on society generally, and in the lives of its marginalized and underrepresented members in particular. Historians recognize Huxley as “the premier advocate of science in the nineteenth century”. He is also recognized as the single most influential person in the democratization of science and science education, for his role in the founding of the journal Nature, as founder and president of many scientific societies, for his work on the Jamaica Committee, and for his work on ten Royal commissions. He is widely recognized for his leadership in the creation of the field of science education, for devising modern K-12 education curriculum for both the privileged and the masses, for bringing college and vocational opportunities to the working class, for fighting for the admission of women to universities, and as history’s greatest popularizer of science for common people. Lastly, Huxley’s life and work contributed significantly to the secularization of society and secular educational institutions like WWU.

Also not acknowledged in the LRTF report is Huxley’s decades-long battle against the idea of scientific racism, and its chief proponent, James Hunt. He also vehemently opposed Hunt and the Anthropological Society for their support of not only the Confederacy, but for the institution of slavery.

I’ll stop here, but, having read the original de-naming proposal and the rebuttal (yes, of course I’m biased), I have to say that the original proposal is not only ignorant, but unscholarly and, at times, illiterate (“homosapien”??). They didn’t even check their sources about things like Huxley’s supposed polygenism (his view was in fact the opposite), and Huxley’s claim that there was a greater evolutionary distance between the “highest and lowest humans” (races) than between the “lowest” humans and the “highest” apes, like chimps and gorillas. That’s not what Huxley said, and the “law”, mentioned only once in the old literature, isn’t even in the consciousness of modern biologists.

One gets the sense that the de-naming proposal was a rush job, confected from dubious sources, ignoring Huxley’s contributions, and designed to give succor to those individuals who claimed that the name of the school caused them “harm” (I’m sorry, but I have trouble working up empathy for that claim). The cancellation of his name may be a done deal, but if it’s not, this new document should change the mind of any rational person. Of course, it’s dangerous to assume that university administrators are rational, as they’re easily swayed by the quotidian breezes of political change.

***********

The pro-evolution website The Panda’s Thumb has also covered this controversy, defending Huxley in three posts (here, here, and here). They also give two other useful links:

Also, today at 8:50 am PDT, Dr. Wayne Landis and I will be making public comments at the BOT meeting, introducing them to the response document and briefly summarizing it.

You may find documentation for the meeting here. The meeting itself will be audiocast here.

Thomas Henry Huxley

 

Response by Brian Charlesworth to the latest episode of Darwin-dissing

June 9, 2021 • 9:30 am

My friend, colleague, and former chair Brian Charlesworth, a well known evolutionary geneticist, had some thoughts about Agustín Fuentes’s op-ed critique of Charles Darwin recently published in Science. (See my own posts about Fuentes here, here, and here.)  As you’ll see, he feels that Fuentes distorted Darwin’s views; Brian attempts a longer and more objective summary.

Fuentes’s thesis was not just that Darwin himself was, on the subject of human evolution, often sexist, racist, and bigoted, but that his views were injurious, justifying “empire and colonialism” as well as “genocide” to those who adopted the thesis of “survival of the fittest.” As I’ve argued before, Fuentes grossly exaggerates Darwin’s bigotry, for although the man shared some of the prejudices of his time, he was far more liberal than the average English gentleman. (For one thing, Darwin was an ardent abolitionist.) Also, Darwin is not responsible, and in fact rejected, the “social darwinism” that justified oppression and conflict by saying it was “natural”.

Brian’s collection of thoughts on Fuentes’s piece is below.  Statements by Darwin himself are indented in normal type, while Fuentes’s statements are indented and italicized.  But first, here’s Brian’s explanation of why he put together the notes; I’ve added a photo of Brian to the bottom of this post.

Why did I compile these notes on Agustín Fuentes’ Science editorial on The Descent of Man, where he accused Charles Darwin of justifying genocide on the basis of the ‘survival of the fittest’? I had previously been a co-author of a paper (Bodmer, W.F. et al. 2021 Heredity ; https://doi.org/10.1038/s41437-020-00394-6) that described the views on eugenics and race of the great statistician and geneticist, R.A. Fisher. This prompted a good deal of criticism, including attempts by an anti-racist group at the University of Edinburgh to have the paper suppressed, on the grounds that it was a “defence of the geneticist R.A. Fisher’s abhorrent views on race and eugenics” (https://twitter.com/UoEREN/status/1374408913861308431). This attracted the attention of the UK national press, with the Daily Mail newspaper asserting that Fisher advocated “sterilisation of people from races he considered ‘mentally inferior’ ” (University of Edinburgh in free speech row over article praising scientist who advocated eugenics | Daily Mail Online).

Both this episode and the Fuentes article raise two issues. First, while I strongly support removing social and racial injustices, I feel that it is important that we examine the context of opinions expressed in past times, and arrive at a judgement of how positive achievements can be recognised, even when some beliefs are expressed that are obnoxious to people today. Conducting such an examination should not be viewed as defending views that are today regarded as abhorrent, as happened to the paper about Fisher. Enormous benefits have accrued to humanity from Fisher’s statistical innovations and from Darwin’s biological discoveries. This contrasts with slave traders, slave owners, segregationists and Nazis, who did nothing but harm. Second, we must get the facts right. Darwin never justified genocide (indeed, he had a lifelong hatred of cruelty in any form); Fisher never referred to ‘inferior races’ or advocated their sterilization.

My notes on the Fuentes article represent an attempt to give a clearer picture of what Darwin actually wrote and thought than was conveyed by the article itself.

****************************************************************************

Some Notes on A. Fuentes’ Science Editorial about Darwin’s The Descent of Man

(Science 2021, 372: 769 DOI: 10.1126/science.abj4606)

Brian Charlesworth, Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh

First, it should be recognized that modern readers of the Descent will find a number of statements and wordings objectionable, notably the use of the terms “lower races” and “savages”. This was, however regrettable, the language commonly used by Victorian writers. It does not shed a flattering light on the prejudices of that age, but it should be recognized that Darwin’s general views on social issues, such as his hatred of slavery and child labour, were among the most enlightened of his time. For example, he was a member of the 1864 committee that urged the prosecution of Governor Eyre of Jamaica for his brutal suppression of protests by the black population.

This aspect of Darwin is barely acknowledged by Fuentes, who remarks that:

“Descent” is often problematic, prejudiced, and injurious. Darwin thought he was relying on data, objectivity, and scientific thinking in describing human evolutionary outcomes. But for much of the book, he was not. “Descent,” like so many of the scientific tomes of Darwin’s day, offers a racist and sexist view of humanity.

This gives a distorted view of the book as a whole. Including Selection in Relation to Sex, there are 954 text pages in the 1874 second edition (John Murray version; the pagination varies among versions), and pp. 319-845 are devoted to animals, not humans. On my reading, the other 45% of the book includes seven passages that express what appear to be racist and sexist views. The most obnoxious of these (p.213) was not written by Darwin himself, but is a lengthy quotation from a Mr Greg concerning competition between Saxons and Celts (the latter being held to be inferior).

[From Fuentes’s piece]:

Darwin portrayed Indigenous peoples of the Americas and Australia as less than Europeans in capacity and behavior. Peoples of the African continent were consistently referred to as cognitively depauperate, less capable, and of a lower rank than other races.

There is only a handful of references to the mental abilities of Africans in the book; contrary to the impression given by Fuentes. Darwin’s statements about mental differences between the races are ambiguous and fluctuating, and many of them are very enlightened compared with remarks by his contemporaries such as T.H. Huxley, Karl Marx and Walt Whitman. For example, on p.276 he says:

“ .. they [races] are found to resemble each other closely in a multitude of points. Many of these are of so unimportant or of so singular a nature that it is extremely improbable that they should have independently acquired by aboriginally distinct species or races. The American aborigines, Negroes and Europeans are as different from each other in mind as any three races that can be named, yet I was incessantly struck while living with the Fuegians on board the “Beagle”, with the many little traits of character, shewing how similar their minds were to ours; and so it was with a full-blooded negro with whom I happened once to be intimate.”

Furthermore, in Darwin’s diary of the voyage of the Beagle (July 3, 1832), he describes the black men of Brazil in complimentary terms:

“I cannot help believing they will ultimately be the rulers. I judge of it from their numbers, from their fine athletic figures … & from clearly seeing their intellects have been much underrated; they are the efficient workmen in all necessary trades.”

It should be remembered that Darwin (and his contemporaries) had no clear grasp of the distinction between genotype and phenotype that is at the core of modern genetics, and he attached considerable significance to the inheritance of acquired characters in the Descent. Therefore, when he referred to race or sex differences in mental traits, it is often unclear whether he thought they were purely cultural in origin, or were innate; but several passages make it clear that Darwin attached considerable importance to cultural factors. When comparing the indigenous inhabitants of New Zealand and Tahiti, he remarked on the effects of education by missionaries on “teaching them the arts of civilization” on the former and the “kind, simple manners” of the latter (Letter to Caroline Darwin, 27 December 1835).

At the end of Chapter 7, Darwin argued forcefully that civilized societies have comparatively recently emerged from barbarian societies and (p.223) noted that:

“The Tahitians when first visited had advanced in many respects beyond the inhabitants of most of the other Polynesian islands. There are no just grounds for the belief that the high culture of the native Peruvians and Mexicans was derived from abroad.”

Fuentes goes on to say:

These assertions are confounding because in “Descent” Darwin offered refutation of natural selection as the process differentiating races, noting that traits used to characterize them appeared nonfunctional relative to capacity for success. As a scientist this should have given him pause, yet he still, baselessly, asserted evolutionary differences between races.

Darwin appealed to sexual selection as a process in differentiating human populations; this is simply a sub-class of natural selection as far as evolutionary mechanisms are concerned.

Fuentes’s statement seems to suggest that he thinks that there are no genetic differences between human populations and that natural selection has nothing to do with them. This is in contradiction with many findings of human population geneticists concerning the action of selection on important traits, such as resistance to malaria, the ability to resist anoxia in high altitude populations, and lactose tolerance in populations that consume milk products. Even without selection, genetic differences between populations in selectively neutral characters can evolve by random genetic drift – subtle differences in the frequencies of large numbers of DNA sequence variants have been revealed even within the population of the British Isles.

Accepting the evidence for genetic differences between human populations carries no implication of believing in racial purity or superiority, or the related pseudo-scientific justifications for discrimination with which we are all too familiar. For quantitatively varying traits, which are subject to both environmental and genetic influences, differences between populations are statistical, in the sense that there is much variability within populations (as Darwin himself noted in relation to human races), which is often greater than any between-population variation. Without complete standardisation of the environment, it is impossible to determine whether observed differences in the mean values of a trait between populations has a genetic basis (this is the basis for the classic “common garden” experiments of plant evolutionary geneticists).

He went beyond simple racial rankings, offering justification of empire and colonialism, and genocide, through “survival of the fittest.” 

There is no evidence Darwin use his science to justify “empire and colonialism, and genocide”. It is true that, like most Victorians, he took a favourable view of British colonization of the Americas, Australia and New Zealand, as shown by some of his statements. But his discussion of the extinction of indigenous populations in Chapter 7 of the Descent emphasised the role of disease and demoralisation, and it is unjust to suggest that he thought that such extinctions were to be applauded.

For example, in his Beagle Diary (4th-7th of September 1833), he exclaims with horror about the massacres of Indians in Patagonia:

“Who would believe in this age in a Christian, civilised country that such atrocities were committed?  … The country will be in the hands of white Gaucho savages instead of copper coloured Indians. The former being little superior in civilisation, as they are inferior in every moral virtue”.

Fuentes also says:

In “Descent,” Darwin identified women as less capable than (White) men, often akin to the “lower races.” He described man as more courageous, energetic, inventive, and intelligent, invoking natural and sexual selection as justification, despite the lack of concrete data and biological assessment. His adamant assertions about the centrality of male agency and the passivity of the female in evolutionary processes, for humans and across the animal world, resonate with both Victorian and contemporary misogyny.

This presumably refers to the following passage on p.858 of the Descent:

“It is generally admitted that with women the powers of intuition, of rapid perception, and perhaps of imitation, are more strongly marked than in man; but some, at least of these, are characteristic of the lower races and therefore of a past and lower state of civilisation.

The chief distinction in the intellectual powers of the two sexes is shown by man’s attaining to a higher eminence, in whatever he takes up, than can woman – whether requiring deep thought, reason or imagination, or merely the use of the senses and hands.”

This was followed by (pp.859-860):

“These latter faculties [various mental traits] … will have been developed in man, partly through sexual selection… and partly through natural selection… Thus man has ultimately become superior to woman. It is, indeed, fortunate that the law of equal transmission of characters to both sexes prevails with mammals; otherwise it is probable that man would have become as superior in mental endowment to woman, as the peacock is in ornamental plumage to the peahen.”

This certainly shows that Darwin believed in the mental inferiority of women, and that this had, at least in part, an innate rather than cultural basis. This was the prevalent view at his time, which persisted until very recently (Fuentes’ institution, Princeton University, did not admit women until 1969, and my old Cambridge college only allowed the entry of female students in 1983).

However, Darwin strongly emphasized the importance of female choice in the evolution of sexual dimorphism in animals, so that Fuentes’ characterization of his views of the role of females in evolution is inaccurate. Darwin even extended it to humans (pp.914-915):

“Preference on the part of the women, steadily acting in any one direction, would ultimately affect the character of the tribe; for the women would generally choose not merely the handsomest, according to their standard of taste, but those who were at the same time best able to defend and support them. Such well-endowed pairs would commonly rear a larger number of offspring than the less favoured.”

Darwin’s theory of sexual selection was not well received, partly because of the emphasis on female choice, and (apart from R. A. Fisher’s advocacy in 1930), it did not start to receive serious attention from biologists until the late 1950s. Today, of course, it is recognized as a major factor in evolution, illustrating Darwin’s originality when he was able to free himself from prejudice.

Fuentes alleges that:

Racists, sexists, and white supremacists, some of them academics, use concepts and statements “validated” by their presence in “Descent” as support for erroneous beliefs, and the public accepts much of it uncritically.

I doubt that characters like Governor George Wallace and Sheriff Clark were much influenced by reading The Descent; in any case, most US racists probably do not believe in evolution.

Darwin scholars have discussed in great detail how a variety of ideologues of very different political persuasions have appealed to Darwin’s writings. Social Darwinism is, of course, notorious. On the other hand, Robert Richards, in his 1986 book (p.526), described how August Bebel, the 19th century leader of the German Social Democrats, thought that “capitalism put artificial restraints on the action of natural selection, so that the idiot son of the factory owner had the advantage over the talented son of the factory worker.” Bebel believed that “the natural forces of progressive evolution would produce a classless society in which property would cease to exist and women would not longer suffer political and sexual subjugation”. Other German thinkers, such as Ernst Haeckel, drew entirely opposite political conclusions; as Richards states (p.533), these contributed to the rise of Nazi ideology. But Richards adds that “The Nazi elite resisted evolutionary theory, despite its scientific charms. After all, could the Aryan race have descended from a tribe of baboons?”.

It seems that, unless you are an out-and-out creationist, you can interpret Darwin to justify almost any a priori belief.

Fuentes concludes by asserting that:

In the end, learning from “Descent” illuminates the highest and most interesting problem for human evolutionary studies today: moving toward an evolutionary science of humans instead of “man.”

First, “man” as used in the title of the Descent is a gender-neutral term referring to “humans”, as was common English language usage until recently.

Second, the last phrase suggests (perhaps unintentionally) that the modern evolutionary biology of humans has hardly moved on since Darwin’s day, and is still burdened with racial and sexist prejudices. This is a misleading caricature; while evolutionary biologists respect Darwin’s towering achievements in founding their field, they recognise that he (inevitably) was wrong about many things, most notably the mechanism of inheritance. There is a damaging confusion here between the views on certain issues of individuals who pioneered a branch of science, and the content of the science as it is currently practised and taught.

Brian Charlesworth

More “evolutionary theory overturned” hype, but, as usual, it’s overrated

October 5, 2020 • 12:45 pm

Once again the magazines are hyping Big New Changes in Evolutionary Theory. This time, though, it’s the respected The Economist, which has a policy of not showing the authors’ names. They should have, for some authors should be given an education about their subject, or at least be held accountable for errors. I am surprised that the website has such a long article, though I don’t often read The Economist, so I was unaware that they did long-form science.

Unfortunately, this is not good long-form science because it distorts and exaggerates the evidence for the role of hybridization in speciation.

First, note the subtitle of the new article below (thanks to many readers for sending it to me). “The origin of species is more complex than Darwin envisaged.” That’s not even wrong. Darwin didn’t advance much of a theory of speciation in The Origin, as he had little idea of what a species was. And what he did say about speciation in that book was, as I note on the first page of my and Allen Orr’s book Speciation, “muddled or wrong.” Nobody touts Darwin as an expert on speciation, despite the title of his great book.

The modern theory of speciation began coalescing in the 1930s and 1940s with the works of Theodosius Dobzhansky and Ernst Mayr, supplemented by Ledyard Stebbins, whose big contribution was to show that in plants, a form of hybrid speciation called “allopolyploidy,” was important in forming new species. All of these authors took speciation to mean the origin of reproductive isolating barriers impeding gene exchange between separate species, with the barriers generally arising by selection causing evolutionary divergence between geographically isolated populations.  If substantial barriers arose as a byproduct of that evolutionary divergence, then speciation had occurred.

That view hasn’t changed much, although our view of how species arise has been a bit refined. But it surely hasn’t been “upturned,” as the article implies: what we know about speciation still rests on a scaffold erected 80 years ago. Yes, of course Darwin’s view of speciation has been completely revised, but we’ve known that for eight decades. It’s like saying, “How genetics has upturned the theory of inheritance,” with the subtitle, “The way heredity works is more complex than Darwin envisaged.”

And the major framework of Darwinism, the five-fold thesis that organisms evolved, that they did so slowly rather than instantly (and in a replacement rather than an individual transformation way), that there is a branching tree of life that began with one ancestral species, that all species, living or dead, have common ancestors, and that the mechanism for creating adaptations (the “match” between an organism, its way of life, and the environment) is due to natural selection—none of these five propositions are affected by the discovery that, as the article notes, hybridization is more common than we used to think. Yes, hybridization is more common than we used to think. What is not true—or at least is unevidenced and probably untrue—is that hybridization is a major cause of speciation in animals. (It is in plants.) But have a read below; The Economist piece is free:

The article was written to show the increasing prevalence of gene exchange between “species” in nature, and, more important, to emphasize that this gene exchange has been instrumental in creating new species. That is, there is a non-Darwinian form of speciation that involves not bifurcation of family trees, but exchange between branches of family trees, leading to new species. That is, here’s how we get new species, and one can say that it is indeed does not lie within the bifurcating-tree framework of Darwinism as limned above (figure from the Evolution paper below):

 

There are two ways this can happen. First, species can produce full hybrids and then the hybrid genome, forming a full population of hybrid individuals, can sort itself out into a new species—that is, a new group of populations that are reproductively isolated from the parental species. And this itself can take two forms. The first, allopolyploidy in plants, involves two plant species with different chromosome numbers (or arrangements) hybridizing, and that hybrid then doubles its number of chromosomes, forming an “allopolyploid” population that will be reproductively isolated from the two parental species. (Hybrids with the parents will produce sterile individuals with three sets of chromosomes.) In my book Speciation with Allen Orr, we show that this kind of speciation is pretty common, accounting for up to 4% of speciation events in flowering plants and 7% in ferns.

The second form of full-hybrid speciation is called “homoploid hybrid speciation”, and involves not an increase in chromosome number, but a normal diploid hybrid forming a population of hybrids, which then evolves into a population reproductively isolated from both parents. The Economist claims this is fairly common. But data I show below suggest it isn’t.

Finally, there is a third way that hybridization can contribute to speciation. That is through introgression: the occasional infusion of genes between species that could be used in adaptation and speciation. (To be part of speciation, those infused genes have to contribute to reproductive isolation between the new “part hybrid” species and its ancestors.) Thus we don’t get an entire population of full hybrids evolving into a new species; rather, speciation occurs in a population that’s taken up a handful of genes from another species through occasional hybrids.  This introgression has happened between modern Homo sapiens and the Neandertals on the one hand and the Denisovans on the other, but it hasn’t lead to new species. That form of introgression is roughly equivalent to mutation on a larger scale, introducing genetic variation that can be (and was, in the case of Neanderthals) used to adapt to environmental changes.

This form of “introgressive speciation”, too, is much rarer than The Economist says, and for the same reasons why homoploid hybrid speciation is rare: we simply don’t have many examples of parental genes in hybrids actually causing the reproductive isolation themselves, though they may cause new morphologies and traits in hybrids that can speciate by more conventional means. (That is, natural selection operates on hybrid or introgressed populations, producing reproductive isolation as a byproduct of the adaptive change, so that genes in the original parents aren’t the cause of reproductive barriers.)

This paper on birds in Evolution, published in 2014, sets out the criteria for homoploid hybrid speciation. Nearly all the examples cited in The Economist piece were already published by then:

Here are the authors’ criteria for homoploid hybrid speciation, the case most emphasized by The Economist:

. . . we define hybrid speciation as a speciation event in which hybridization is crucial in the establishment of reproductive isolation. Although we agree with previous reviews on the definition, we focus this piece on establishing standards for the genetic and phenotypic evidence required to demonstrate that homoploid hybrid speciation has occurred. To demonstrate that hybrid speciation has occurred given this definition, three criteria must be satisfied: (1) reproductive isolation of hybrid lineages from the parental species, (2) evidence of hybridization in the genome, and (3) evidence that this reproductive isolation is a consequence of hybridization. By contrast, a large number of empirical studies have simply used genetic evidence of hybridization (Criterion 2) as support for hybrid speciation (see below).

In our discussion, we evaluate the strength of evidence for homoploid hybrid speciation in studies published in the last decade against these three criteria. We argue that much of the evidence presented in proposed cases of homoploid hybrid speciation does not provide strong support for the hypothesis of hybrid speciation. In addition, we outline the evidence required to support hybrid speciation and suggest promising directions for future studies.

The criteria, though stringent, seem quite reasonable to apply to claims of hybrid speciation. I won’t go through all the analysis, but just present this graph of how many cases fit each of the authors’ three criteria. Plants are in dark green, fungi in lighter green, and animals in very light green. Note the y axis is number of studies, and it goes up to only fifty. The last column are the cases that fit all three criteria, that is, cases that might well represent homoploid hybrid speciation. Note how low the bar is!

For meeting all the authors’ criteria for homoploid hybrid speciation (last column), we have three cases in plants (all involve the superb work of Loren Rieseberg’s group on sunflowers in the genus Helianthus), none in fungi, and exactly one in animals, the hybrid butterfly species Heliconius heurippa. 

The “Big Bird” case of a hybrid species of Galápagos finch that starts out The Economist‘s article isn’t considered, but it, too, is a bit problematic, as it involves a very few finches that show some reproductive isolation but are in a population of very recent origin that hasn’t been examined in about a decade, as I recall. If that small population persists and remains reproductively isolated from the two other finches on the island, we’ll have one more case in animals. That would make a total of five cases of homoploid hybrid speciation among all three groups examined, and that’s a very small number. It’s certainly not enough cases to say that this kind of hybrid speciation has been at all common, much less ubiquitous. Now it may be that there are more cases that we simply don’t know about, but until we find them, we’re not justified in saying that they’re common, much less that “evolutionary theory is upturned.”

A related paper published in 2018 examines claimed cases of hybrid speciation in birds. Click on the screenshot to read it:

Author Jente Ottenburghs examines seven purported cases of hybrid speciation in birds, some of which are mentioned in the Economist piece.  He uses two criteria for whether bird speciation is homoploid hybrid speciation, the same type considered by Schumer et al. above. That is, these are cases in which a hybrid population is supposed to have evolved into new species. And, like Schumer et al., he judges the evidence on whether the reproductive isolation comes directly as a result of the hybridization, which is true hybrid speciation, or whether the hybrid population evolves reproductive isolation by more conventional processes, like natural selection acting on new mutations to create evolutionary divergence—with the byproduct of reproductive isolation—in geographically separated populations.

Ottenburghs finds only one convincing case of homoploid hybrid speciation in birds: the “Big Bird” case of incipient speciation in Galápagos finches. He finds just three cases in which species form after hybridization but the reproductive isolation is not the direct consequence of hybridization (Audubon’s Warbler, likely to be renamed by the Woke), the Golden-crowned Manakin, and the Italian Sparrow.  So even here, in a group where hybrid speciation is supposed to be common, we have fairly convincing evidence in only four cases.

The upshot.  Considering eukaryotes—I’m not dealing with bacterial “species” here, a complicated issue discussed in Speciation—we have at most five cases of true homoploid hybrid speciation, and then a few more cases of speciation after hybridization in which the reproductive isolation evolves by conventional Darwinian means. There is a difference between hybrid speciation and speciation that occurs via neo-Darwinian processes in a population of hybrids.

In other words, we don’t have near enough data to “overturn evolutionary theory”, or to say that new species often don’t form by a branching process. As far as we know, Darwin’s bifurcating tree is still good for nearly all eukaryotes.

Nor do we think that “Darwin’s concept of speciation as a slow and gradual process” is overturned by homoploid hybrid speciation, which, if it evolves via normal processes of selection and drift, could still be very slow. Yes, polyploidy is quick (a new species arises in three generations), and is not something Darwin considered. But allopolyploidy (the hybrid form of polyploid speciation) has been recognized as an important form of speciation in plants since at least 1950, when Ledyard Stebbins published Variation and Evolution in Plants, drawing plants into the Modern Evolutionary Synthesis. Well, that was 70 years ago. Allopolyploidy is important, but it’s old news.

But one thing we know now that we didn’t know before, and I think I’ve emphasized this, is that introgression—genes moving into species from other species—is more common than we used to think. This comes from the molecular innovations that have made such introgressions detectable. But that doesn’t mean that hybrid speciation is more common than we used to think. In fact, it may well be less common than we used to think.

It seems to me that The Economist‘s policy of not naming the authors of its pieces is not a good one for stuff like this, for the author, whoever he or she is, is represented as giving scientific facts and conclusions. If they’re exaggerated or misrepresented, the author should be held accountable.