Category: evolution

Can celebrity endorsements help people accept evolution?

November 19, 2018 • 9:00 am

The short answer to the question above is “yes”. Or so suggests new research on acceptance of evolution published in Evolutionary Psychology (click on screenshot below; access free with Unpaywall app and free pdf is here).

The method: Several samples of people from Canada (most from a “small university in northern Ontario”, probably Nipissing University) were given one of three fictitious passages to read; these passages were either pro-evolution, anti-evolution, or neutral (the last was a summary of a work of fiction). Participant’s religious beliefs as well as demographic data were also taken. There were four experiments in total, and I’ll summarize the results briefly. One of the passages involved my book, though it wasn’t from my book; I’ll put that in along with the “antievolution passsage” as examples of the readings (pictures of the book covers were also included):

1.) Acceptance of evolution after reading the three passages. After controlling for sex and age, the three passages by themselves had no effect on participant’s acceptance of evolution as judged by the often-used MATE test, which has 18 questions. In other words, reading about evolution (or fiction) didn’t affect a person’s short-term acceptance of evolution. (Although acceptance/rejection wasn’t assessed before reading, the passages were randomized among the 150 subjects, presumably taking care of stuff like religiosity—which was negatively correlated with acceptance of evolution).

The fact that students’ reading of the three passages had no overall effect on their MATE scores set up the scenario for the rest of the study, which involved adding endorsements to the passages: endorsements by either an “expert” in evolution (a fictitious professor) or a celebrity (George Clooney or Emma Watson, chosen for their likability and recognition.

2.) Endorsements by a male celebrity vs a male expert; student population. Students again were randomly assigned one of the three passages, and this time each passage was accompanied by a heading indicating it was from a magazine article called “Celebrity book review”, with the celebrity being George Clooney, or “Expert book review”, with the “expert” being fictitious American university professor George Rooney. Thus we have six conditions, with pro-evolution, anti-evolution, and neutral passages, each with an endorsement by a celebrity or expert. Remember that both celebrity and expert could endorse either pro- or anti-evolution stands.

The result was that, compared to the initial non-endorsement condition shown in 1.) above, a celebrity endorsement or a pro-evolution passage raised acceptance of evolution compared to the neutral condition, while Clooney’s endorsement of an anti-evolution passage lowered it compared to the neutral condition. In other words, a celebrity endorsement had an effect on acceptance of evolution.

This was not seen when the three passages were endorsed by an evolution science expert; here there was no effect. The figure below shows the effect of Clooney’s endorsement (left three bars) compared to Rooney’s (right three bars):

(From paper) Figure 1. Mean differences in acceptance of evolution scores across opinion (proevolution, anti-evolution, and control) and purveyor (celebrity, expert) conditions. †p < .01. *p < .05. **p < .01. ***p < .001.

3.) Endorsements by a celebrity vs an expert; “community” population. Here the authors did the same test, but used only Clooney and not the expert, and surveyed 157 people “recruited form various public locations. . . in a small city in Northern Ontario, Canada.” There was no assessment of the passages themselves without endorsement, but the authors apparently assumed that reading the passages themselves had no effect on the MATE score—as was found in the student population.

The result was the same: there was a significant difference between treatments in the expected direction (effects weren’t that large for the pro-evolution endorsement), showing once again a celebrity effect (see below). As I said, there was no test of endorsement by an expert scientist. But there’s a problem because there was no initial test of the effects of the passages themselves, without endorsements, on the “community members”, so there’s that critical assumption that the community mirrors the condition of the students.

(From paper) Figure 2. Mean differences in acceptance of evolution scores across opinion (pro-evolution, anti-evolution, and control) purveyed by a male celebrity among a community sample. †p < .01. *p < .05. **p < .01. ***p < .001.

4.) Endorsements by a female celebrity; student population. Here the celebrity was Emma Watson rather than George Clooney, and there was no comparison with an evolution “expert” (who would presumably have been a woman scientist). Let me show why they chose Watson:

Emma Watson was chosen as the female celebrity because she was included in Time Magazine’s 2015 list of the 100 most influential people. Additionally, AskMen.com (2015) placed her at the top of its list of the Top 99 Outstanding Women, in part because she is “rich, successful, famous, stylish, beautiful, intelligent, personable, and kind.”

Well, that’s more or less the same criteria used for Clooney. And once again the celebrity endorsement had an effect on the data from 158 students recruited from that same “small University in Northern Ontario” (why do they hide its name; it’s obvious!). Here are the data for Watson’s endorsement; the direction and size of the effect (i.e. the degree to which endorsement of evolution increased acceptance or criticism of evolution decreased acceptance) was about the same for Watson or Clooney.

(From paper): Mean differences in acceptance of evolution scores across opinion (pro-evolution, anti-evolution, and control) purveyed by a female celebrity. p < .01. *p < .05. **p < .01. ***p < .001.

The upshot. In this study, among all three groups (with the caveats given above), celebrity endorsement of a position on evolution changed students’ or the population’s views on evolution in the expected direction, whether that endorsement be an affirmation or a criticism. In other words, evolution is like a product that can be sold more readily if a celebrity endorses it (the authors cite data showing positive effects of such endorsement in commercials).

Further, a celebrity had a much bigger effect than that of a fictitious “expert”. In fact, endorsement or criticism of evolution by a scientist had no effect. These celebrity effects occurred irregardless of the effect of participants’ religiosity, which itself was negatively correlated with acceptance of evolution.

Of course there are limitations of these tests. The authors mention the limitation of much of the study to undergraduate students, and to a “young, Western, educated, industrialized, rich, and democratic sample.” Maybe celebrities don’t have an effect on other populations.  But the authors don’t mention another significant issue: the effect was measured only in the short term, presumably within an hour after reading the passages. We don’t know if this kind of “priming” has any long term effect on acceptance of evolution, which you’d need to measure a long time after the students read the passages. What we’re like to see is long-term acceptance, not short-term acceptance.

I guess I’m not surprised at the result, as we know that people tend to accept ideas more readily when those ideas are endorsed by members of their “tribe,” and I suppose that people like Clooney and Watson, who are widely admired, can be considered members of the Canadians’ “tribe.” It’s not clear whether people can see a scientist as a member of their tribe.

But what action does this result suggest if we want people to accept evolution? I suppose it couldn’t hurt to have celebrities endorse evolution, though I’m not aware of any who have. (Of course, celebrities, at least in Hollywood, tend to be liberal and Democratic, and so probably would endorse evolution). So by all means let’s get the NSF to gather celebrity endorsements and publicize them.

Since I’m not a celebrity, though, all I can do is talk about the data supporting evolution, as I’m no George Clooney! Maybe a combination of a scientist and celebrity, as with people like Brian Cox (previously a rock star) or Neil deGrasse Tyson, would work better than scientists alone.

All I can say is that if endorsements work over the long term, that’s fine; but people should also look at the data supporting evolution rather than simply relying on either scientist-experts or celebrities. After all, you can understand why evolution is true without fancy degrees in science.

Richard Prum explains homosexuality as the evolutionary result of selection for female autonomy

October 23, 2018 • 12:15 pm

I’ve talked a few times about Richard Prum’s new book The Evolution of Beauty, which asserts that female choice drives the evolution of male sexually dimorphic traits in nature, like fancy plumage and mating dances. That’s not in doubt, but Prum’s big claim is that what females are seeking in mates are arbitrary “aesthetic” features of males not connected with their vigor or genetic endowment. He calls this the “Beauty Happens” model, and it’s a version of the “runaway model” of sexual selection proposed by Ronald Fisher, Russ Lande, and Mark Kirkpatrick.

While Prum’s book has its good bits, it’s pretty misleading about the evolution of sexual behavior, as I pointed out on a review on this site.  As I wrote,

The book’s problem is that it is tendentious. Prum doesn’t describe the issues with his favored runaway model; he mistakenly regards it as a “null model” against which other models must be tested since, he wrongly claims, it makes no assumptions (he also claims that his null model can neither be proven nor disproven, which makes it non-scientific); he neglects other forms of sexual selection; he does not recognize that various models can work together and likely do work together; he ties “good genes” models to eugenics and even Nazi eugenics, unfairly tarring sexual selection theory with the residue of an unsavory past; and he claims that female choice of mates, which he calls “sexual autonomy”, somehow vindicates feminism in our own species.

Not only does Prum take a very one-sided view of how female mate choice evolves, but lards his book thickly with the idea that female choice in animals (mostly birds) is somehow a vindication of feminism in humans. This is, of course, known as the Naturalistic Fallacy. Not all female animals have sexual autonomy, and one could draw very different lessons from observing deer or other species in which males compete with each other, and the female gets the winner. Alternatively, there are animals like bedbugs, in which female “sexual autonomy” is obliterated by “traumatic insemination”, in which males inject sperm directly into the female body cavity, sometimes injuring or even killing her. Equal rights and opportunity for women should come from moral contemplation, not from observing what animals do. If you tie your biology so closely to your ideology or morality, you risk having to alter your ideology when we learn new facts that aren’t relevant. Should a student of bedbugs be opposed to women’s rights?

Prum also ties “good genes” models (those models in which females choose males because they have ‘good genes’ that will improve the fitness of their offspring) with Nazi eugenics. As Prum says on pp. 328-329:

“To permanently disconnect evolutionary biology from our eugenic roots, we need to embrace Darwin’s aesthetic view of life and fully incorporate the possibility of nonadaptive, arbitrary aesthetic evolution by sexual selection. . . Accordingly, evolutionary biology should adopt the nonadaptive, Beauty Happens null model of the evolution of mating preferences and display traits by sexual selection”.

That’s just ridiculous. We reject scientific theories not because they have antecedents in politically unsavory views and behavior, but because they’re not supported by the data. Connecting the good genes models with Nazi eugenics is a sleazy and musteline tactic. But it’s this connection between Prum’s theory and politics on the one hand and feminism on the other that has made his book quite popular—in my view, way too popular given its problems. I’ll have more to say about this at a future date.

Throughout the book, Prum suffers from what I call The Big Idea Syndrome (TBIS): the view that his idea has nearly universal explanatory power. (A similar victim of TBIS was Lynn Margulis, who thought that endosymbiosis explained nearly everything about biology, including the formation of new species).

One of the things that Prum proposes, toward the end of The Evolution of Beauty, is that homosexuality in humans also evolved as a result of females seeking to exercise sexual autonomy—their evolutionary “need” to have free mate choice. Prum explains this in a short  Big Think talk (transcript here):

Here’s a bit of the transcript, with my comments:

So individuals that are attracted to the same sex are frequently imagined to evolve because they provide help to their kin, that is, if there are some people in any social group that are non-reproductive because of their sexual preferences then they will be helping with raising of their nieces and nephews. This is sort of the “helpful uncle” hypothesis. The problem with that idea is that it should actually lead to a kind of asexual phenotype or an asexual behavior; it doesn’t actually describe the evolution of sexual attraction itself.

What he means at the end is “same-sex sexual attraction”. And yes, it’s possible to become nonreproductive if by so doing you actually gain fitness by taking care of your relatives (this is possible if your own sacrifice of your genes by not reproducing is more than compensated by the passing of your genes through the relatives you tend). This in fact is one explanation for the sterility of worker bees. But  Prum’s right that becoming nonreproductive doesn’t necessarily explain why the “gay uncle” is gay. He could just be asexual. And I don’t accept this hypothesis, but I’m not sure there is an evolutionary explanation for homosexuality. Nevertheless, Prum ignores evidence that is in favor of the “gay uncle hypothesis“, including some surveys in which gay men seem more willing than straight men to help relatives. (That’s only weak evidence, of course, but it’s evidence.)

Here’s his theory about how homosexuality (including lesbianism) evolves by the “Beauty happens” theory (my emphasis):

Well the aesthetic view of evolution proposes that we should put subjective experience—that is, the nature of animal and human desire—at the center of our scientific explanation. So in order to explain same sex attraction in people we need to actually ask: how could same sex attraction actually evolve?

Well, in the book I propose that human same sex attraction evolved specifically because it contributed to female sexual autonomy or to the freedom of choice. What I mean by that is that in the case of female/female sexual relationships they could contribute to female alliances that could protect females from sexual coercion by male hierarchical groups.

At the same time I propose that male/male sexual attraction could have evolved because any social situation in which males have multiple sexual outlets would have contributed to female freedom to move among individuals in that social system and to avoid coercion and sexual violence. This is a new aesthetic theory of the evolution of same-sex behavior in people, and I think it’s one that deserves really serious consideration as we move forward.You can read the book for a fuller explication.  The first paragraph explains lesbian relationships: they evolve because genes for lesbian same-sex attraction would help females bond and thus gain them female autonomy.  The problems with this are several. Why would male genes become unable to overcome the female “love bonding”? Why wouldn’t females just form coalitions without necessarily having it be a coalition based on sex? Bonobo females may show same-sex behavior, but female lions in prides don’t.

Further, if these genes are adaptive in our species, which is what Prum wants to explain, why haven’t they spread to fixation? That is, same-sex attraction in human females is not universal. (In fact, I think the evidence that it has a significant genetic component is not strong, though there is some evidence for a genetic basis of male homosexuality.) Yet it should be ubiquitous if Prum is right. So Prum’s explanation doesn’t explain why fewer than 100% of women are attracted to other women.

I suppose one could claim that the genetic influences have been overridden by culture, but that’s special pleading. Or one could claim that lesbian same-sex behavior is simply a side effect of selection for female “prosociality”, and when females are prosocial and bonding, a certain tail of that distribution will show lesbian behavior. But that’s not what Prum says: in the bolded bit above, he says that same-sex attraction was selected because it contributed to female sexual autonomy, not that same-sex attraction is a side effect of genes selected for sexual autonomy.

His argument for male/male sexual attraction is even weaker. Again, it fails to explain why fewer than 100% of males have homosexual tendencies; if the genes were useful (like the genes for female preference themselves, or for the male traits, like lion manes, which female favor), then why aren’t they seen acting in all individuals, just as Prum sees female preference and male traits? Again, given what Prum says, saying that some gay behavior is simply a side effect of females selecting for “nicer, gentler, and kinder males” who are noncoercive doesn’t fly.  Further, why wouldn’t male attraction to other males be at some disadvantage because males are wasting their reproductive effort in a way that doesn’t spread their genes? Prum may respond that females prefer to mate with homosexual males because they’re “noncoercive”, and that preference can outweigh the reproductive cost of gay males courting other males. But how this would get off the ground in an evolutionary sense defies me.

Until there are data supporting all of these ideas, Prum should do the responsible thing and keep his yap closed, or at the very least point out the problems with his own theories. That, in fact, is a recurring issue with the book: Prum doesn’t mention at all the problems with the “Beauty happens theory.”

But of course if he did that he wouldn’t get attention and book sales. In the process, however, he’s lost some of his credibility as a scientist. He’s not only in love with his Big Idea, but, like many scientists, appears to be enamored as well with the attention he gets. Take The Evolution of Beauty with a huge grain—nay, a big hill—of salt.

h/t: Tom

The Great Sacred Ibis Debate: an episode in the history of evolutionary biology

October 4, 2018 • 1:15 pm

While evolution became a big deal in 1859 with the publication of Darwin’s Origin, there were of course people who had the idea of evolutionary change before him. One of these was Jean-Baptiste Lamarck (1744-1839), who suggested that organisms had evolved over long periods of time, but who has become infamous for suggesting that that evolution involved phenotypic changes according to an animal’s “will” that altered heredity via use and disuse of parts (the giraffe evolving a long neck by stretching it to reach high branches is the classic example).

In contrast, his fellow Frenchman, the influential zoologist and naturalist Georges Cuvier (1769-1832) argues for the “fixity of species”: because species’ parts were optimally adapted to each other, species could not and did not change over time.

Their conflicting view of evolution, and how they were subject to a test, albeit a flawed one, is described in this article in the new PLoS Biology (click on the screenshot, reference below and pdf is here).

The tale is brief.  When Napoleon and his army invaded Egypt at the end of the 18th century, they found and recovered many animal mummies, which included not only the famous cats, but also jackals, dogs, snakes, the sacred ibis, and of course humans. Many of these were brought back to Paris and put in museums. And there there were lots of them: the paper notes that the catacombs at one site alone contained 4 million mummies of the Sacred Ibis. That bird became the bone of contention between Lamarck and Cuvier.

First, here’s a picture of the extant African Sacred Ibis (Threskiornis aethiopicus), considered sacred as a representation of the Egyptian god Thoth, who, among his other attributes, maintained the Universe. I put a picture of Thoth below the Ibis; his head is that of the bird:

African Sacred Ibis
Thoth

And here are some mummified Ibises (their wrapped bodies were put in pots); the caption is from the paper.

(from paper): Fig 2. Mummified Sacred Ibis. (A) Empty and full pottery vessels from catacombs from Saqqara, Egypt (photo credit Sally Wasef), (B) mummified Sacred Ibis wrapped in cloth (photo credit Metropolitan Museum of Art, New York), (C) a well-preserved example of an unwrapped Sacred Ibis mummy (the head and wings of the bird are clearly visible), and (D) a mummified Sacred Ibis dipped in resin.

The presence of 3,000 year old Ibises afforded a one-way test of whether the bird had evolved. If the mummified Ibises were very different from present-day ones, then one might claim that evolutionary change had occurred. If not, then Cuvier would claim that their stasis supported his view that species were fixed. (It’s a one-way test because the finding of “no change” could still be consistent with slow evolution.)

After a bit of a mixup between the Sacred Ibis and a similar bird, the yellow-billed stork (Mycteria ibis), Cuvier managed to show that the mummies he studied were indeed the same species as the African Sacred Ibis of today. But had they changed at all? He measured the body parts of mummy skeletons and modern ibises, and the paper gives the data (an assertion, really, with my emphasis below):

Based on these measurements, Cuvier correctly established that the mummies were not storks. He determined that the mummified birds matched the unclassified birds from the museum. Cuvier went on to name these birds Numenius ibis, and they have subsequently been reclassified as T. aethiopicus (Sacred Ibis). Cuvier also recovered a few uniquely shaped black feathers from a mummy that provided further evidence for his identification of the mummified birds as ibis. To Cuvier’s knowledge, these distinctive black feathers were a characteristic of the genus Numenius . Cuvier preserved these feathers for future examination as “a remarkable monument of antiquity and a peremptory proof of the identity of species”.

The measurements of the mummified bones were not a perfect match with those taken from the museum specimens of Sacred Ibis. However, the measurements between the ancient material and the then-contemporary Sacred Ibis were similar, and Cuvier concluded that no detectable anatomical changes had occurred over time. This made him the first to test the idea of evolution.

The debate went on at the French Academy of Science, and Cuvier properly replied that, after all, these birds were only 3,000 years old, and that wasn’t enough time to expect much evolutionary change.

The results thus seem inconclusive, but Cuvier’s objection was reasonable. I’m not sure what the upshot was among zoologists, as the authors don’t report this, but it’s really a one-way test of evolution, and not a very good one given that there was “not a perfect match” between the measurements of extant versus mummified ibises. “Similar” is not “identical”, and some evolution might indeed have taken place based on the measurements.

Still, this is an interesting episode in the history of evolutionary biology, and a “test” of evolution that preceded Darwin by several decades. What surprises me is that this episode is well known to historians of science and to some evolutionists (I’m not among the informed), and I don’t really see a good reason for publishing it in a premier biology journal. Still, I was glad to learn the story, and perhaps you will be, too.

__________
Curtis C, Millar CD, Lambert DM (2018) The Sacred Ibis debate: The first test of evolution. PLOS Biology 16(9): e2005558. https://doi.org/10.1371/journal.pbio.2005558

Dear BBC: Yes, we are descended from monkeys. And no, evolution and religion are not compatible.

September 26, 2018 • 8:45 am

Yesterday I wrote a bit about the BBC’s new seven-question “Test your knowledge of evolution quiz” (quiz here, my posts here and here), which was (and is) larded with ambiguous questions and wrong answers. They’ve now changed the irrelevant religion question (#7), which originally said, “Evolution and religion are incompatible. True or false?” (the answer was “false,” of course). It now reads “Evolution and religion are not necessarily incompatible. True or false?”. Now that’s a confusing double-negative question, but the answer still touts compatibilism:

Well, we all know that the Beeb is soft on faith (note their “daily affirmation,” or whatever they call the prayer they broadcast each morning), so it’s no surprise. But the question itself palpably does not test one’s knowledge of evolution. It tests whether one is soft on faith. Depending on your definition of “incompatible,” either answer could be right.

Further, they now say that “evolution is not about the origins of life”. First, that’s not necessarily true, since life emerged from nonlife through an evolutionary process, probably involving something like natural selection on combinations of chemicals. But the statement itself implies that if one does consider the origin of life as part of evolution, then evolution is incompatible with religion.  Now why is that? Presumably because evolution is incompatible with the origin story told in Genesis I and II.  If so, then evolution does become incompatible with religion, since Genesis also tells the story of how animals and plants came to be. This is a real confusion on the part of the BBC. At the very least, they have to admit that the story of life—and methodological naturalism—are incompatible with religion.

Further, the Beeb changed the question without any indication that it did so. It was my impression that when a journalist changes an article, the change from the original piece must be indicated on the piece, as an addendum. That’s not done here: more irresponsible (and sneaky) journalism.

At any rate, the question below is still alive, as shown by the tweet below it:

Matthew, Greg and I all think the Beeb got it wrong here. If you’re a strict cladist, you might say that, no, humans did not descend from monkeys; but under the common usage of “monkeys”, yes, our common ancestor would have been recognizable as a monkey.

But the BBC wasn’t thinking of cladism here; it was trying to refute the old creationist trope: “If humans descended from monkeys, why are there still monkeys?”

Here’s a refutation of the BBC’s answer as tweeted by a paleontologist:

 

I’ve enlarged the phylogeny so you can see it.

Finally, one more plaint. The answer to the question, below, even as given by the BBC, is ambiguous. For the answer notes that, if you define progress as “improved abilities to survive and reproduce” under exigent conditions, then yes, evolution does result in progress. It’s only not progressive when you define progress as “getting more complex”, “getting more like humans”, or moving toward some specified goal. The whole question and answer is deeply ambiguous and, like most of the other questions, the BBC should have deep-sixed it.

They missed a good chance to educate people about what evolution is and what the theory says.

The BBC changed the religion/science accommodationism question on its evolution quiz

September 25, 2018 • 1:00 pm

As reader Eric astutely pointed out, the BBC has now changed question #7—the “accommodationism” question—in the evolution quiz I described this morning. It previously read this way:

Now it reads this way:

I’m fairly sure, but not positive, that calling attention to this question by myself or others has led to the change. It’s an improvement for sure, but I emphasize again that this question has no place in a quiz about evolution. It’s a theological or philosophical question that doesn’t test anybody’s knowledge about evolution. What gives, Beeb? You in bed with Templeton?

Further, the “right” answer depends on what you mean by “incompatible”. If you construe “compatibility” as “some people can be both scientists and religious,” then of course they’re compatible. But if you construe it as “compatible in using comparable methods to ascertain what’s true”, then it’s false. My whole book Faith Versus Fact is about this issue.

But the entire quiz is very shoddy, as several readers pointed out. Virtually every question is ambiguous or wonky. I don’t follow BBC science reporting much, but letting this quiz slip by without some vetting by good British evolutionists (e.g. our own Dr. Cobb) is bad journalism.

So it goes.

 

BBC gives a dumb quiz on how much you know about evolution

September 25, 2018 • 8:15 am

Readers Dom and Kevin called my attention to this new quiz on the BBC website that supposedly tests your knowledge of evolution. It was compiled with the help of Dr. Paula Kover, who teaches evolution at the University of Bath.

Click on the screenshot to take the seven-question quiz. I got only 5/7, but that’s because the quiz is badly screwed up!

I won’t reveal six of the science questions (the seventh, below, has nothing to do with science), but I will say that question #5 is deeply screwed up, and the “correct” answer is either wrong or, at best, ambiguous. It could have been phrased better. Matthew and I both think it’s just wrong. (See here for an explanation.)

Matthew and I also objected to question #6. I won’t tell you what it is, but Matthew said it’s ambiguous because “better” is not defined. I agree. If you define “better” as “having increased fitness”, then the answer they give is wrong.

As for question #7, it has NOTHING to do with science, but is simply a sop to religion. And it’s personally insulting because I wrote an entire book supporting what the BBC says is the wrong answer. Here’s the question—guess what they consider the “right” answer:

The BBC could have done a much better job with this quiz since nearly half the questions come with either ambiguous or incorrect answers. So it goes.

 

RadioLab distorts some science

September 23, 2018 • 12:00 pm

There’s been a lot of publicity about David Quammen’s new book, The Tangled Tree: A Radical New History of Life, which tells the story of the discovery of a new domain of life, the Archaea, the discovery that chloroplasts and mitochondria are the remnants of anciently absorbed microbes, and, most novel, the recent discovery of horizontal gene transfer (HGT): the transfer of DNA and genes between relatively unrelated organisms. Most of the publicity about the book—to be sure, publicity pushed by Quammen himself—centers on HGT. It is, we’re told, something that radically overturns Darwin’s view of the “tree of life” and of evolution, and even revises our own view of “what it means to be human” (after all, we’re also told, a substantial part of our genome is dead, nonactive DNA from ancient retroviral infections).

A month ago today I reviewed the book in the Washington Post (see my postmortem post here), and was pretty critical of the way Quammen handled HGT. While the phenomenon is fairly common in bacteria, it’s less common in eukaryotes, and hasn’t dramatically altered our view of evolution in either case, much less having changed our view of ourselves. Even horizontally transferred genes must be subject to natural selection if they’re to spread as adaptations, and they certainly haven’t messed up evolutionary trees in eukaryotes, for people are still busy reconstructing the history of life using such trees. (Indeed, the delineation of Archaea as a separate domain of life depends on their being a discernible evolutionary tree.)

Nevertheless, Quammen still promulgates his spiel widely, most recently in a National Geographic interview and, more invidiously, in the RadioLab interview below (click on screenshot). After all, the man has books to sell. But I wish he’d tone down his rhetoric.

Both Quammen and the show’s hosts (Robert Krulwich and Jad Abumrad) seem to promulgate the misconceptions about HGT, and I hope RadioLab isn’t becoming more uncritical. I can’t enact the emotional labor to dissect every error in this 30-minute show, but here are a few bizarre things to which I took exception:

1.) Krulwich says that Quammen’s book shows that HGT and perhaps endosymbiosis (origin of mitochondria and chloroplasts) are “a smack in the face to Darwin’s theory of evolution.” Well, not really. They are revisions of how genetic variation comes to enter a species’ genome, but, as I said in my review, HGT doesn’t really efface Darwin’s “tree of life.” And it hasn’t affected our view of adaptation via the disposition of random genetic variation by natural selection.

2.) In the classic story of the peppered moth Biston betularia, the show tends to cast the spread of the “melanistic” mutation in the moth during industrialization as a refutation of “incremental mutation”. But it’s wrong to say that the old idea was that the color difference was due to several mutations, or happened gradually,. We have long known that the change in color from peppered white to dark was the result of mutation in a single gene, and that the English population became transformed quickly: within a few decades. Further, when pollution controls were passed, the moth quickly reverted to its ancestral peppered form.

The change was not, as Krulwich says, instantaneous. And just because the gene change was due to a “transposable element”” that moved within the moth genome (i.e., not HGT) rather than a change in one nucleotide does not affect the Darwinian nature of the change one bit. It just shows that the “mutation” was a big one involving translocation of a big chunk of DNA into the moth’s cortex gene. No revision of Darwinism needed, especially because Darwin didn’t even know about genetics, so you could equally well shout that genetics itself was a “smack in the face to Darwin’ s theory of evolution”. The whole characterization of the “original” Biston story as “incremental mutation and very slow evolutionary change” is a straw man”—not even wrong.

I wrote to my old undergraduate advisor, Bruce Grant, who worked extensively on Biston. He listened to the RadioLab show and had this to say:

The “review” of the classic peppered moth story is garbled and grossly misrepresents it. No one has ever argued for incremental mutations. There are multiple alleles that produce a range of intermediates collectively called insularia, with the darkest, fully melanic phenotype called carbonaria. It acts as a qualitative autosomal dominant, fully melanic from the get-go wherever it occurs (besides the UK, in North America and Japan). Its frequency increased via directional selection, and its frequency has also decreased by directional selection. Further, these changes have been parallel in both directions on separate continents (US and UK), in concert with documented changes in air quality assessed by suspended particulates ( soot).

The DECLINE in melanism has been much better documented than its increase. There are mountains of data. Those taken by Cyril Clarke include nearly 20,000 specimens collected at one location near Liverpool from 1959 to 2001+. Insularia (intermediates) have always been rare there. Effectively only two phenotypes have been involved: fully melanic carbonaria and the “typical” peppered form. The reduction in the frequency has been gradual, did NOT involve intermediates and fell from well over 90 % to under 5 % in 40 generations. Now carbonaria has all but disappeared there. I witnessed this decline personally from 60 % onwards. It’s real and intermediates (insularia) were always rare there.
Parallel changes have occurred independently in Michigan. All this has been published and is supported by hard data. The RadioLab people do NOT know what they’re talking about.

What Quammen is probably confused by is Ilik Saccheri’s evidence that transposons may be responsible for the original mutation. But there are still some reservations about that I spelled out during my talk at CoyneFest. I do think that Ilik oversells his work, and shortchanges others in the process, but surely he’d still object to Quammen and the hosts’ interpretation of Industrial Melanism.

3.) The suggested idea that the first billion years of life involved pervasive HGT, and that individuals and species weren’t easily delineated, is just that—speculation. Species and well delineated individuals could have arisen quite early, for all we know.

4.) Krulwich’s claim that HGT shows that evolution “can happen a lot faster than we thought” isn’t really true. A horizontally transferred gene is just a big mutation, and in many cases will sweep through the population just as rapidly or as slowly as a mutational change in the organism’s own DNA. What’s important is how strong natural selection is. And we already knew that evolution by conventional mutational changes in genes can happen quite quickly, even without HGT. (Biston is an example of that, as is the 10% change in beak size in one year in the medium ground finch revealed by the work of Peter and Rosemary Grant and their group.)

5.) Once again we hear the claim that the human microbiome and the presence of viral DNA in our genome means that we have to revise the notion of who we are, and “what it means to be human”. But that’s bogus, too—just a sensationalistic way to sell books. The fact is that I don’t wake up every morning and think, “Geez, my gut is full of E. coli and my DNA full of retroviruses. I have to rethink what it means to be Jerry Coyne!”

6.) There is a clear implication that Carl Woese contributed to work on HGT. This is not the case: his work highlighted in Quammen’s book was in discovering the domain of life comprising the species within the new group Archaea.

7.) Finally, it is overblown to think that HGT and endosymbiosis means that the categories of ‘individual organism’ and ‘species’ become blurry. Is Homo sapiens a real group or an arbitrary construct? The former, for sure. And I am Jerry Coyne, not a mixture of Jerry Coyne and Donald Trump (thank god!).

So listener beware when you hear this discussion on NPR. I wish Krulwich & Co. would have been a bit more critical rather than credulous consumers of Quammen’s sensationalism.