Category: evolution

A new book correctly criticizes the idea that some species are superior to others, but mistakenly claims that species aren’t real

January 29, 2023 • 10:10 am

The Berkeley News, the publicity site for the University of California at Berkeley, has a piece out announcing a new book that was published out in December (photo below). Since it was published by the venal and greedy Springer, the hardback of Speciesism in Biology and Culture will cost you only $159.

Click on the screenshot below to read about the book, which comprises nine essays rejecting humans’ view that we are the top and most important species, and that species can be ranked by their “superiority”. With that rejection I wholeheartedly agree. But there’s another theme, too: one which I think is misguided: species aren’t even real. Click below to read the article, which has a summary of the book.

Here are the book’s two themes:

In a new book, a group of scientists and philosophers places part of the blame on an attitude prevalent among scientists and the general public — the false belief that species are uniquely real, and that some species are superior to others.

To the researchers, this is analogous to racism — the fallacious belief that races exist as branches on the tree of life, and that some races are superior to others.

Now I agree that there is no hierarchy of species: we just happen to be the one that evolved a big brain with which we can control all other species, and an organ we can use to pat ourselves on the back as better than others. (A flea doesn’t have the capacity to see itself as superior to other species—but it can suck their blood!).

But the view that species are not “uniquely real” is a gross distortion. Species are far more real and discernible than human “races”, whose demarcation is somewhat subjective although even the “classic” races are not totally invented social constructs (they contain biological information).

If species weren’t real, however, there would be no problem of “the origin of species”, and nature would be a spectrum—a rainbow with no joints between its constituents. Orangutans, gorillas, and humans would all be arbitrary entities: “social constructs”. So would pigeons, starlings, robins, and cardinals. But I’m getting ahead of myself. A few more excerpts about the supposed non-reality of species:

Mishler has argued for decades against considering individual species as the most important grouping, particularly when discussing conservation. [JAC: actually, in the U.S. it is subspecies that are the units that must be conserved.] He laid out his arguments in a 2021 book, What, If Anything, Are Species? ( CRC Press), in which he proposed getting rid of taxonomic rankings altogether, including the binomial system for naming species that is used universally today. [JAC: As you know, this idea hasn’t caught on, nor will it.]

One key reason is that species distinctions are not equivalent across all branches on the tree of life. Bacteria that look identical may vary as much genetically as a dog from a cat, while some birds that live in totally different areas and look different can be nearly identical genetically. On the other hand, lineages — the sequence of organisms that have evolved from one another over millions of years — are consistent across all forms of life.

“Evidence shows that a species of amoeba does not mean the same thing as a species of fungus, animal or anything,” Swartz said. “And if species are not uniquely real, then where does that leave us? Is there anything that means the same thing across the tree of life? The answer to that question is: lineages. These are branches on the tree of life that maintain genealogical connections across time and space. They include children, or descendants, and their parents, or ancestors, on through animals broadly and their distant relatives. Lineages are branches across the tree of life.”

Throwing out the concept of species would eliminate the artificial dividing line that helps justify the belief that some species are more important. Instead, the authors maintain that humans are just one part of a genealogy connecting all living things. This interconnectedness forms an ecological web that sustains the planet and us, and that deserves to be protected equally with humans.

Mishler goes one step further, arguing that lineages should be respected — not for how they can benefit humans, but intrinsically, as part of the web of life. He detests the term “ecosystem services,” which implies that the natural world exists to service humanity.

. . .The authors point out that the standard definition of a species is a population that cannot breed with closely related populations. But Mishler said this definition is muddied by the fact that there is often wide variation within a breeding population; sometimes two separate species can and do successfully interbreed, and some species don’t breed at all.

. . .“Alan Templeton summarized it most succinctly: The trouble with species is too little sex and too much sex,” he said. “There are asexual groups that don’t do sex at all, but still have lineages. And then there are plants, like the orchid, which can just about be crossed with every other orchid, yet they’re bizarrely different from each other. So, reproductive compatibility, while a nice idea, just doesn’t work empirically.”

Species also can evolve because they get separated geographically or ecologically, not because of an inability to breed.

A more natural grouping is by lineage — ancestor-descendant pairs connected across time — or by clade, which consists of all the descendants of a creature.

Mishler and his colleagues have argued for years that species aren’t real, but their views haven’t gained any traction in the biological community beyond those few people who already reject the reality of species. Perhaps that explains this book.

The biological species concept (BSC), used by nearly all evolutionists, including me, is based on reproduction: a species consists of a group of populations whose members can exchange genes with each other, but cannot exchange genes with members of different species—where the different species live in the same area in nature—because there are barriers that impede genetic exchange between different species.

Now the entire first chapter of our book Speciation, by Coyne and Orr, is a defense of the BSC, a discussion of its problems (no, it’s not perfect), and an argument that it’s superior to all other species concepts because it gives us a handle on why organisms in nature don’t form a spectrum (see the Appendix for a discussion of alternative species concepts, including “lineage concepts” mentioned by Mishler).

First, the question of whether species are “real” is the same as the question “is nature a continuum or lumpy?”. That is, when we look at organisms like mammals or birds or trees in one place, do we see a continuum of variation that we can partition only subjectively, or are there discrete entities that are recognized widely as distinct? And for nearly all groups of sexually reproducing organisms, nature is lumpy. You already know this if you try to identify birds or mammals or other sexually reproducing organisms in the wild. We don’t have a spectrum of birds but, in one area, you see a series of discrete types that you can easily identify. Those groups (in one area; see below) are biological species: robins, starlings, pigeons, etc. etc., and are formally recognized with Latin binomials.  They are real, and you or Joe or Jill can easily slot what you see into a small number of bird groups—species. The lumpiness of nature in one area is, in fact, THE “species problem”, the problem that, despite the title of his book, Darwin didn’t answer. (He didn’t answer it because he had no knowledge of genetics and therefore no concept of reproductive barriers.) We need to explain why, in one area, we see a number of discrete forms and no intermediates (or only a few, which could be hybrids that are often sterile.)

The answer to the species question is that reproductive barriers, which are many (we have a chapter on each type in Speciation), keep species distinct by preventing any blurring that would occur with gene flow. Though hybridization between species in one area is more common than we used to think, in most groups it is rare, and if the hybrids are sterile or inviable, then they pose no problem for “blurring” species boundaries.

Now some caveats, for the BSC isn’t perfect:

a.) The BSC is meant to apply to sexually reproducing organisms because it’s based on genetic exchange between individuals or the lack thereof. In organisms like bacteria that are largely asexual, you can’t use it easily. Now whether those organisms form clumps as discrete as those seen in sexually-reproducing species isn’t clear: few people are interested in that topic, which I think is important. This issue is discussed at the end of the first chapter of Speciation.

b.) Two groups must usually live in the same place if you are to determine with certainty whether they are members of different species. If they do not form hybrids that are viable and fertile where they co-occur, they are different species. This is true, for example, of the lion and tiger, which used to co-occur in India before the lion was extirpated. They formed no hybrids in nature. (They sometimes do in zoos, but that’s because captivity can eliminate some reproductive barriers that occur in nature, like aversion to mating with other species. I call this the “prison effect”).

c.) If two similar species live in different places, it’s hard to tell if they’re different species or simply different populations of the same species. If you bring them together in the zoo or lab and they do not hybridize, or form sterile or inviable hybrids, then they are different biological species. But if they do form hybrids, even some fertile ones, the question is still unresolved, for, as I said, some true biological species hybridize in captivity but not in the wild. One can only guess in such circumstances. This kind of guessing is what biologists do when they designate very similar populations that live in different areas as “subspecies”. The “zoo or lab” tests are one-way: they can tell you that populations living in different areas are members of different species, but can’t tell you for sure that they’re members of the same species.

d.) Speciation is a process, usually occurring between geographically isolated populations of a single species. With no possibility of gene exchange, these populations begin to genetically diverge due to various processes like natural selection, sexual selection (a subset of natural selection), genetic drift, and so on. If that divergence occurs to the point that, when the different populations re-establish geographical contact, they do not exchange genes, then full speciation has occurred. But it need not occur: there are many time when populations aren’t isolated long enough to become reproductively isolated, and in that case they can re-establish contact and exchange genes. Those are not members of different species. (This re-establishment of contact is why human populations did not evolve into different species.)

Or, there could be some reproductive isolation but it’s not complete. In such cases we have to make a judgment, like calling them “incipient species” or “groups with incomplete reproductive isolation.” It turns out that there are evolutionary processes that, upon re-contact of incompletely isolated populations, can drive them, though natural selection, to evolve into different and full biological species. One such process is called “reinforcement”, and it’s been seen to work in both nature and the lab.

The upshot is that because the evolution of one species into two or more is a continuous process, there will be stages of the process in which there is some reproductive isolation but it’s not complete. (Geographically isolated populations will, if left long enough, nearly always become full species). That means that there will sometimes be problems establishing whether two populations are species or not. I like to say that spatially isolated populations become more and more “species-like” with time, and, when reproductive isolation is complete, finally attain the status of full biological species.

e.) The reality of species is also seen by common sense (the value of bird guides, for example), by the remarkable coincidence between indigenous people and outside scientists in recognizing the same groups existing in one location, and through using statistical methods to see if individuals fall into discrete phenotypic or genetic clusters. This is the very first topic we take up in our book, and provide ample evidence that clustering in one area is real, and that the same clusters are identified by both local residents and biologists from outside the area, establishing that the clustering is not simply the result of humans subjectively partitioning a continuuum of nature into discrete units.

If you think that species aren’t real, go outside for half an hour and look at birds. If you know your birds, do they form a continuum, or does each bird you see fall neatly into a group that has been recognized, described, and written up in bird guides? You already know the answer. Bird species are real, and that’s true in other groups of plants and animals.

I could go on, but if you can get hold of Speciation by Coyne and Orr, I’d suggest reading Chapter 1, which gives evidence for the reality of species. Since our book was taken over by Oxford University Press, it’s now as expensive as the one above, so try to get it from a library. Chapter 1 is, I think, accessible to the scientifically interested layperson. (The book, however, is written for professional evolutionists: grad students, advanced undergrads, or professional evolutionary biologists. I always tell my friends not to read it unless they’re willing to slog through the stuff meant for professional evolutionists.)

So yes, species are real in sexually-reproducing organisms, but there are intermediate cases because it’s a process that takes a lot of time—evolutionary time. Finding cases that are hard to decide does not negate the value of the BSC, for, in the end, it’s the genetic barriers between species that allow them to continue diverging from each other without “pollution” by genes from other populations. In other words, it is the evolution of reproductive barriers that produces the lumpiness of nature that we see in one area.

And that is the great value of the BSC: it explains why nature is lumpy, a question that wasn’t answered by evolutionists until around 1935 or so. It answers the species question, at least in sexually-reproducing organisms.  The concept of genetic barriers (reproductive isolation) gives a natural explanation for nature’s lumpiness, and thus the question of “the origin of species” in sexually reproducing groups boils down to the question of “the origin of genetic barriers. And that gives us something to work with at last! How do those barriers arise, and what is their nature? As I wrote in Speciation, I don’t know of a single study on the origin of species of plants or animals in nature that is not about the origin of genetic barriers and reproductive isolation. That’s how pervasive and useful the BSC has been!

As for the “lineage concept” of species, it’s deeply confused, and you can read the Appendix of my book to understand why. Just one point here: what lineages are we talking about? Lineages of genes are different from lineages of populations, and those differ from lineages of biological species. Species concepts based on using lineages of genes, for example, always wind up in a big muddle, and have not been used to answer the question of why nature is “lumpy.”  Insofar as lineages are constrained to remain separate, it’s because they’re reproductively isolated! But read the book to see more. Or look at any intro text on evolutionary biology, like this one.

In short, yes, I agree that no species is better than any other, or has any kind of natural hegemony over other species. That idea is crazy, though of course humans do kill and eat members of other species. But that doesn’t mean that we’re better than, say, cows—any more than lions are “better” than gazelles. So here I agree with the book’s authors.

But I think their view that species aren’t real is deeply misguided. It is, I think, an example of what I call “the reverse appeal to nature.” This is what I call the tendency to impose onto nature your own ideological or biological prejudices. The regular philosophical “appeal to nature” is the misguided idea that “what is natural is good”. (It’s similar but not identical to the “naturalistic fallacy,” which is “what we see in nature is what we ought to do.”)

The reverse appeal to nature simply stands that appeal on its head, saying “what we think is good must be what occurs in nature.” Another example of is using ideology to deny that there are two sexes in nature because you have an ideology that maintains that biological sex is a spectrum. You must thus claim that what exists in nature must be what your ideology tells you exists. This is why we see the pervasive ideological denialism of what is a palpable truth recognized by biologists. (And yes, there are only two sexes in humans and other animals.)

Perhaps the ideology behind the “species are not real” claim is that if you don’t think there should be a hierarchy of species, you can simply deny that species exist. But you don’t have to deny the existence of species to be kind to animals.

If you have questions about species or speciation, I’ll try to read the comments within a day and answer them. Or, best, consult this:

John Scopes and his University of Chicago connection

December 16, 2022 • 9:15 am

John Mark Hansen is, according to the University of Chicago website, “the Charles L. Hutchinson Distinguished Service Professor in the Department of Political Science and the College. He is also one of the nation’s leading scholars of American politics.”  Yesterday I got an email from him with some local history about John T. Scopes, who as you know was the man tried for teaching human evolution in the 1925 “Monkey Trial” in Dayton, Tennessee.

John’s email said this:

As you may know, I did a historical guide to Hyde Park and Kenwood that came out right before Covid hit. I’ve been adding to it for a hoped second edition as I come across things. Here’s one that might interest you. Did you know Scopes was a student here? This story is not in the book but it has a lot more.

His book is called The City in A Garden, and you can find it here.

He sent me the proposed section about Scopes, and it had a lot of stuff in it that I didn’t know (I did know he was a U of C student, but that was about it). Here, then, John fills out the record on the estimable John Scopes (posted here with permission).  The addresses given are quite close to where I live in Hyde Park.

The Monkey Trial

In May 1925, a grand jury in Dayton, Tennessee, indicted John T. Scopes for violating a state law forbidding the teaching of evolution. The American Civil Liberties Union, which had solicited a test of the law, engaged Clarence S. Darrow (1537 E. 60th) to lead the defense. Soon after, Darrow convened a group of experts from the University of Chicago to advise his team on issues of science and religion. Horatio Hackett Newman (PhD’05, 5712 Dorchester) was a professor in zoology and the author of Readings in Evolution, Genetics, and Eugenics (1921). Fay-Cooper Cole (5710 Blackstone) was a newly-tenured professor in anthropology and a writer of popular articles on human origins. Shailer Mathews (5736 Woodlawn) was a theologian, the dean of the Divinity School, a public lecturer on “The Contributions of Science to Religion,” and the editor of a book of the same title (1925), to which Newman had contributed a chapter on “Animal Evolution.” Darrow knew them as participants in a “biology group” that had met in his home for discussion for about ten years. Finding no lack of scientists eager to defend the theory of evolution, the defense’s roster quickly expanded to include Charles H. Judd (1320 E. 58th), a psychologist and the chair of the University’s education department, and Kirtley F. Mather, a Chicago native and alumnus of the University (PhD’15), then a professor of geology at Harvard, among several others. In the event, the judge in the case refused to allow Newman and his colleagues to testify, thwarting the defenders’ intention to put the premise of the law on trial. In July 1925, the jury convicted Scopes and fined him $100. The trial earned notoriety not only for Scopes and Darrow but also for their academic supporters. Back in Chicago, Professor Cole received a summons from Frederic Woodward, a law professor acting as president after the death of Ernest DeWitt Burton. Woodward showed him resolutions from a convention of southern Baptists condemning him, Newman, Judd, and Mathews for their participation in Scopes’s defense. Reading their objections, he began to laugh but Woodward caught him short. “Already we have had more demands for your removal than any other man who has been on our faculty,” Woodward told him. In fact, he continued, the resolutions had been discussed by the Board of Trustees. Suddenly sober, Cole asked about their response. Woodward handed him a piece of paper. “They had raised my salary,” Cole recounted decades later.

Here’s Scopes in 1925 at the time of the trial:

Photo courtesy of John Scopes, Jr.

After the trial, Scopes was unemployed and unwelcome in Tennessee. After considering law school, he decided to enroll in the doctoral program in geology and paleontology at the University of Chicago. The scientists took up a collection to pay his first two years of tuition. Darrow and his wife Ruby met him at the Illinois Central station at 63rd and boarded him until he was able to rent a room on 63rd Street. Although preoccupied with his courses in geology, he told reporters he also hoped to audit H. H. Newman’s class, Zoology 101, “The Nature of the World and Man,” but he managed only to sit in on Fay-Cooper Cole’s lectures. For his work in the program, Scopes was elected to Kappa Epsilon Pi, the geology honorary society, and the science honorary society Sigma Xi. In the spring of his second year, as his funding came to an end, the department nominated him for a fellowship that would have enabled him to complete his doctoral studies but the president of the “well-known technical school” that administered it refused to consider the application. “As far as I am concerned,” he wrote Scopes, “you can take your atheistic marbles and play elsewhere.”

Scopes left the University and took a job with Gulf Oil in Venezuela. Three years later, having lost the job in the Depression, he returned (recently married) to finish his degree. His intended advisor, a paleontologist, had died in the meantime. He found a new supervisor, Edson S. Bastin (PhD’09), the department chair, and formulated a new research plan in economic geography. By the time he completed additional coursework and his fieldwork in New Mexico, however, “my Venezuela money [had] played out and with the end nearly in sight I had to stop and attend to needs more pressing than the quest for a doctoral degree.” Scopes never finished his doctorate. He worked the rest of his career as a geologist in the oil and gas industry, living in Shreveport, Louisiana.

In 1959, the University of Chicago convened a conference to mark the centennial of the publication of On the Origin of Species (and the sesquicentennial of Darwin’s birth). Twenty-five hundred scientists, scholars, educators, and journalists attended the five-day event in Mandel Hall, including the grandsons of Charles Darwin (also Charles) and T. H. Huxley (Julian). Of the Chicago participants in Scopes’s trial only Cole was still alive but he was retired in California. The chair of the conference committee, the anthropologist Sol Tax (5537 Woodlawn), invited Scopes to the proceedings but he demurred, still averse to publicity even three decades later. (The international conference concluded with a hometown production, the debut of “Time Will Tell,” a “musical satire” based on incidents from the life of Darwin, composed and written by Robert Ashenhurst (5624 Dorchester) and Robert Pollack (1312 E. 56th), a business school professor and an investment broker, respectively. Ric Riccardo, “The Singing Restauranteur,” played Darwin and Jo Anne Schlag (5810 Harper) his wife Emma.) In 1960, however, Scopes returned to the campus. He was the featured guest at the premiere of a 28-minute film produced by Encyclopædia Britannica to document the Origins centennial conference. After the screening, Scopes, three professors, the sales manager of the University of Chicago Press, and Tax as moderator participated in a roundtable discussion on the status of evolution in science teaching in the United States. The law against teaching evolution was still on the books in Tennessee, a participant pointed out, and Mississippi and Oregon besides. In other states, textbook publishers resorted to euphemisms to finesse the controversy surrounding the concept. Away from teaching and the academy for a third of a century, Scopes had little to add. “I hope that I don’t ever have to go through something like that again,” was all he would say about his experience in Dayton.

Scopes in 1970, the year he died.

(From source): On April 1, 1970, John Scopes gave a lecture at Nashville’s Peabody College (now part of Vanderbilt University). Here he speaks with Tennessee state legislators Harold Bradley (center) and Charles Galbreath (right), who were key in repealing the 1925 Butler Act. Photo from the collection of Todd Hatton.

At the gravesite of Scopes and his wife, Paducah, Kentucky:

Queen Mary University professor rejects evolution and promotes the New Testament in his inaugural lecture

December 12, 2022 • 9:15 am

Here we have an hourlong talk by Richard Buggs, Senior Research Leader (Plant Health & Adaptation) at Royal Botanic Gardens Kew, and Professor of Evolutionary Genomics at Queen Mary University of London. We met Dr. Buggs on this site in 2021 as “a creationist professor of evolutionary biology in England,” where he touted Intelligent Design;  I included a shorter video in which Buggs mixed his God with his science. Now he’s doing it again in his Inaugural Lecture at Queen Mary University (below).

His personal webpage gives his bona fides:

Professor Richard Buggs is an evolutionary biologist and molecular ecologist. His research group analyses DNA sequences to understand how plants, especially trees, adapt in response to climate change and new pests and pathogens. Richard has published on a variety of evolutionary processes including: natural selection, speciation, hybridisation and whole genome duplication. The birch species Betula buggsii is named after him. Richard is a Christian, and sometimes blogs on issues where biology and Christianity intersect.

He’s also author of the 2007 Guardian article below (click if you want to read):

A quote from the article:

But, whatever the limitations of Darwinism, isn’t the intelligent design alternative an “intellectual dead end”? No. If true, ID is a profound insight into the natural world and a motivator to scientific inquiry. The pioneers of modern science, who were convinced that nature is designed, consequently held that it could be understood by human intellects. This confidence helped to drive the scientific revolution. More recently, proponents of ID predicted that some “junk” DNA must have a function well before this view became mainstream among Darwinists.

But, according to Randerson, ID is not a science because “there is no evidence that could in principle disprove ID”. Remind me, what is claimed of Darwinism? If, as an explanation for organised complexity, Darwinism had a more convincing evidential basis, then many of us would give up on ID

Back to the talk. This is a very bizarre lecture. In the first half he denies the existence of branching evolutionary trees, arguing that this invalidates both Darwinism and natural selection (note: although evolution is required for such trees, natural selection is not).

To do this, he cherry-picks data in which a few independent trees, derived from both morphological and DNA data, are not concordant. But that does happen under evolution, for sometimes genes are transferred horizontally, or via hybridization, or we have “incomplete lineage sorting”, in which segregating ancestral genetic variation is distributed among descendants. Further, if you use only a few genes—and note that Buggs’s trees are based on only a few genes—you may get a “gene tree” that’s discordant with the “species tree”—the actual history of new lineage formation via splitting. Allen Orr and I discuss this discordance in the Appendix of our book Speciation. The upshot is that you don’t expect every gene to give the same tree, but if evolution and evolutionary splitting occurred, you would expect the preponderance of genes to give the same tree. And they do, save in the rare case when there’s been pervasive hybridization between groups, and the species involved are fairly closely related.

Buggs also dwells at length on the relatively sudden appearance of angiosperms, almost implying that it supports sudden creation, though he ignores the fact that monocot plants appear far earlier than angiospemrs in the fossil record, so the data don’t support the evidence of any creation. (Note: Buggs implies that the fossil record and molecular data support a religious scenario rather than an evolutionary one, but is very canny about mentioning Biblical creationism or Intelligent Design.)

Buggs’s denigration of evolutionary trees constitutes, he claims, evidence for a Designer (aka God/Jesus). AT 30:00. for example, he argues that the NON-existence of evolutionary trees supports a Designer, for if a system were designed rather than evolved, you wouldn’t expect concordant trees; you’d get “a bit of a mess”.)

At 39:38, Buggs shifts gears and tells the baffled audience (listen to the tepid applause is at the end!) that well, maybe the evolutionary “tree of life” doesn’t exist, but the BIBLICAL tree of life does! This “tree of life” stands for eternity and all the claims of Christianity, for the words “tree of life” appears in Revelation (2:7 and 22:1-3).  Here’s a summary of Buggs’s “evidence” for the Bible:

In other words, because many people believed in Christianity, and John had a revelation, Christianity must be true (his words are “we should not lightly dismiss John’s claims”).  How little it takes to convince Buggs of the New Testament’s truth, and how much it would take to convince him of evolution! (Remember, he concentrates ONLY on the existence of trees as evidence for evolution, ignoring things like development, the fossil record, biogeography, observations of natural selection in action, and all the stuff I adduce in Why Evolution is True.)

I’d urge you to at least listen to the last 20 minutes so you can see how a scientist can be so credulous that he’s persuaded that Christianity is true based on the thinnest evidence you can imagine.

Finally, BUGGS goes woke at the end, promoting “inclusion” in STEM, but he apparently does as a way to promote religion. For, as the sweating Dr. Buggs shows, Christianity is most pervasive in “countries of color”: those in sub-Saharan Africa and Latin America (also the U.S., but he ignores that). His conclusion? We need to include RELIGION more in the sciences, and be nicer to believers, because that will attract more “non diverse” people into STEM. This is a very weaselly proposal for sneaking religion into the sciences!

In the end, Buggs distorts and misrepresents what science has told us, ignores the pervasive evidence for evolution besides evolutionary trees, and gives an embarrassingly thin account of “evidence” for Christianity.

Yet this man is a professor of evolutionary biology and molecular ecology! His presence at Queen Mary University of London, much less his promotion to Professor, reflects very poorly on his university. I’m not urging his dismissal, though if he were teaching this guff at a public university in America he’d be violating the First Amendment and should be told to leave the religion out of his teaching. Now it’s possible that Buggs doesn’t mention Jesus or the Bible in his classes, and that would be great. But I truly doubt that he gives a good account of the evidence for evolution, either. (After all, he accept Intelligent Design, not evolution.) That is, I suspect Buggs’s students are being shortchanged, and if that’s the case, I feel sorry for them. As for Queen Mary University, I’d merely suggest that they check if Buggs is dragging religion into his teachings.

h/t: Gerdien

Readers’ wildlife photos

December 3, 2022 • 8:15 am

It’s been a while since we’ve had an illustrated biological tale from Athayde Tonhasca Júnior, but we get one today—on the work of one Ch. Darwin on orchis. Athayde’s prose is indented, and you can click on the photos to enlarge them.

Evolutionary dead ends and sticky contrivances: Darwin the botanist

Athayde Tonhasca Júnior

In 1842, the Darwin family – Charles, his wife Emma, and their two children William and Anne – moved to Down House in the village of Downe, England. The Darwin patriarch, who had travelled the world aboard H.M.S. Beagle (1831–1836), would spend the remaining 40 years of his life in quiet isolation at home because of ill-health. Darwin’s condition (whose origin still puzzles scholars) did not slow him down; he embarked on several projects such as monographs on coral reefs and barnacles, and of course overseeing the publication of On the Origin of Species. But Darwin spent most of his time working with plants, which are convenient study subjects for someone with a sedentary lifestyle. Assisted by gardeners and occasionally his children, Darwin observed and experimented with cabbage, foxglove, hibiscus, orchids, peas, tobacco, violets and many other species in his garden and glasshouse.

The Old Study at Down House, where Darwin completed On the Origin of Species by Means of Natural Selection. Evolutionists are encouraged to go on pilgrimage to Down House provided they are physically and financially capable.  [JAC: it’s not expensive and is close to London. Anybody interested in Darwin and evolution MUST go! And the town has two lovely pubs.]

Darwin’s glasshouse at Down House, where he conducted many experiments © Tony Corsini, Wikimedia Commons.

Among various major contributions to botany (detailed by Barrett, 2010), Darwin documented the importance of cross-fertilisation (i.e., the transfer of pollen between different plants) for producing healthy offspring. Ever meticulous about supporting his theories with data, Darwin amassed eleven years of continuous observations to highlight the superiority of cross-fertilisation over self-fertilisation, i.e., the transfer of pollen within the same flower or between different flowers on the same plant.

Indeed, the great majority of flowering plants predominantly or exclusively outcross – that is, they mate with other individuals – even though they could easily self-fertilise because they are hermaphroditic (their flowers contain both male and female sexual organs). In fact, numerous flowers have mechanisms to avoid self-fertilisation. At best, many self-pollinating species (or ‘selfers’) exhibit mixed mating systems.

The bee orchid (Ophrys apifera). Despite its name, this orchid is mostly a selfer in northern Europe. In the Mediterranean, where this orchid is more abundant, its flowers are pollinated by bees © Bernard Dupont, Wikimedia Commons. [JAC: note that some petals have evolved to resemble a female bee. When a male sees the flower, he tries to mate with it, and the pollen sacs above his head stick to the body.  Frustrated, he flies away with the pollen, forgets about being duped, and tries to mate with yet another flower, whereby cross-fertilization is effected. This is a great example of a plant mimicking an insect. See more below.]

Self-pollination has some advantages: it helps to preserve desirable parental characteristics when a plant is well adapted to its environment. Because selfers do not depend on pollen carriers, they can colonise new habitats with a handful of individuals. Selfers do not have to spend energy on nectar, scents, or substantial quantities of pollen. Self-pollination is useful to farmers, as the genetic identity of a variety or cultivar is easily maintained, without requiring repeated selection of desirable features.

Self-pollination sounds like a convenient and rational lifestyle, but there are catches, and they are considerable. Selfers’ limited genetic variability makes them vulnerable to environmental changes; a hitherto well-adapted population can be driven to extinction if no individuals are adapted to novel conditions – and changes are inevitable, given enough time. Selfers are also particularly susceptible to inbreeding depression:  if the population is homogeneous, genetic defects cannot be weeded out by genetic recombination.

Taking into consideration the long-term hazards of selfing, it seems paradoxical that 10 to 15% of all flowering plants from many taxonomic groups made the transition from outcrossing to full self-fertilisation. Darwin proposed an explanation for this puzzle: cross-pollinated species would turn to self-fertilisation when pollinators or potential mates become scarce. In other words, self-fertilisation assures survival when outcrossing becomes inviable. Darwin’s hypothesis, currently known as the ‘reproductive assurance hypothesis’, continues to be the most accepted explanation for the evolution of self-fertilisation.

Remarkably, researchers were able to quickly induce the transition from cross-pollination to self-pollination in the common large monkeyflower (Erythranthe guttata, previously known as Mimulus guttatus) by preventing plants’ contact with pollinators (e.g., Busch et al., 2022). Monkeyflowers kept in a glasshouse with no pollinators for five generations increased the production of selfing seeds and showed a reduction in the stigma to anther distance – this feature, known as herkogamy, is one of the indicators of ‘selfing syndrome’: the greater the distance between stigma and anther, the greater the likelihood of the stigma receiving external pollen, thus the lower the chance of self-pollination. After nine generations, plants experienced a significant reduction of genetic variability. Monkeyflowers kept in another glasshouse with free access to the common eastern bumble bee (Bombus impatiens), one of the plant’s main pollinators, underwent none of these effects.

L: The common large monkeyflower, a native to western North America. Its wide corolla and landing platform are convenient for its main pollinators, bumble bees © Rosser 1954, Wikimedia Commons. R: Diagram of a large monkey flower with the upper corolla removed to show the reproductive structures © Bodbyl-Roels & Kelly, 2011.

A common eastern bumble bee; its absence induces selfing in large monkey flowers © U.S. Geological Survey Bee Inventory and Monitoring Lab.

What do these observations about the monkey flower tell us? For one thing, they are cautionary tales about the risk of losing pollinators. A variety of human disturbances such as agriculture intensification, loss of habitats, and diseases have caused a decline of some insect populations, including pollinators. A scarcity of flower visitors may threaten pollination services directly, or induce some plants to adapt quickly and become self-pollinated. Adaptation sounds good, but selfers’ lower genetic diversity and reduced capacity to adjust to environmental vicissitudes make them vulnerable to extinction.

The renowned botanist and geneticist G. Ledyard Stebbins (1906-2000) suggested that selfing is an evolutionary dead end: it is advantageous in the short term but harmful in the long run. And because the transition from outcrossing to selfing is irreversible, according to Dollo’s Law (structures that are lost are unlikely to be regained in the same form in which they existed in their ancestors), self-fertilization ends up in irretrievable tears. And the monkeyflower has shown that it all may happen before we notice it.

While Darwin worked in his garden, somewhere in the British countryside a four-spotted moth (Tyta luctuosa) landed on a pyramidal orchid (Anacamptis pyramidalis), intending to sip some nectar. The moth certainly didn’t expect to end up with its proboscis – the elongated mouthparts used for sucking by butterflies and moths – covered with blobs of pollen. But that was the least of the moth’s problems, as disaster loomed: the hapless wanderer was captured by an unknown collector and became a model for George B. Sowerby (1812-1884), the illustrator of Charles Darwin’s masterpiece about orchid fertilisation – On the Various Contrivances by Which British and Foreign Orchids Are Fertilised by Insects, and On the Good Effects of Intercrossing.

An illustration from Charles Darwin’s book on fertilisation of orchids depicting the head of a four-spotted moth with its proboscis laden with several pairs of pollinia from pyramidal orchids. Names of the species involved have changed since then.

Those globules of pollen attached to the moth’s proboscis are known as pollinia (sing. pollinium). Each unit contains from five thousand to four million pollen grains, depending on the species. The grains are stuck together with pollenkitt, an adhesive material found in almost all angiosperms pollinated by animals. A stalk-like structure connects the pollinia to a gluey pad known as viscidium, and the whole assemblage is often referred to as a pollinarium.

A pollinarium: the pollinia on the toothpick are held in place by the sticky viscidium © Frederick Depuydt, Wikimedia Commons.

Pollen grains lumped together in a sticky package are not easily carried away by water or wind. As Darwin learned from his observations and experiments, this is done by animal vectors, mostly wasps and bees (although moths, beetles, flies and birds do the job for a reasonable number of orchid species). Having pollen grains in a single unit reduces wastage during dispersal, but it’s a risky strategy: a lost pollinium means no pollination at all. So orchid flowers have undergone dramatic morphological transformations to assure that pollinia are picked up by the right pollinator:

‘If the Orchideæ had elaborated as much pollen as is produced by other plants, relatively to the number of seeds which they yield, they would have had to produce a most extravagant amount, and this would have caused exhaustion. Such exhaustion is avoided by pollen not being produced in any great superfluity owing to the many special contrivances for its safe transportal from plant to plant, and for placing it securely on the stigma. Thus we can understand why the Orchideæ are more highly endowed in their mechanism for cross-fertilisation, than are most other plants.’ (Darwin, 1862, Fertilisation of Orchids).

What are some of these contrivances mentioned by Darwin? Orchids’ stamens (comprising anthers and filaments, the male reproductive parts) are fused with the pistil (which are the female reproductive parts: stigma, style and ovary) to form a structure known as a column. The anther (the pollen-producing organ) is located at the distal – away from the centre – end of the column, and the stigma (the pollen-receiving organ) lies close by. Directly below the column there’s an enlarged petal named labellum or lip, which often is noticeably different from other flower parts in its colour, markings, or shape. For nectar-producing species, nectaries are located at the base of the labellum.

Parts of an orchid flower © Thomas Cizauskas, CC BY-NC-ND 2.0:

So the stage has been meticulously set. The distinct labellum is a perfect landing strip for an insect attracted by the orchid’s rewards, be they real (nectar) or not (when physical or chemical decoys are deployed). The pollinator lands on the labellum, touches the tip of the column, and goes away with pollinia securely adhered to its body by the viscidium, which works better on smooth surfaces such as the eyes and mouthparts of insects and beaks of birds. When the pollinator visits another flower, the pollinia are likely to be transferred to the stigma. Sticky pollinia and viscidium ensure secure removal of pollen, minimal losses during transit, and a high probability of deposition on a receptive stigma.

An orchid bee (Euglossa sp.) with pollinia attached to it © Eframgoldberg, Wikimedia Commons:

These morphological features have evolved independently in two plant groups: orchids (family Orchidaceae) and milkweeds (subfamily Asclepiadaceae of the family Apocynaceae). But pollinia are relatively more important for orchids; with more than 26,000 described species, they make up about 8% of all vascular plants and span a range of habitats in all continents except Antarctica; there are more orchid species in the world than mammals, birds and reptiles combined.

Orchids’ highly specialized ‘lock and key’ pollination system reduces the chances of pollen being picked up by the wrong flower visitor or being transferred to the wrong plant species; the selective adaptations towards the right flower-pollinator association must have contributed to orchids’ enormous richness and diversity of forms. It’s amazing what a dab of glue here and there can do.

A figure from the 1877 edition of Fertilisation of Orchids. A pencil inserted into the flower of an early-purple orchid (Orchis mascula) comes out with an adhered pollinium. Within 30 seconds, loss of moisture bends the stalk forward. If the pollinium was attached to a bee, it would be perfectly positioned to touch a receptive stigma.

Evolution falls on hard times in Turkey

November 17, 2022 • 12:15 pm

Although Turkey is a member of NATO and is one of the most Westernized countries in the Middle East, its government is becoming increasingly conservative and, since the election of Recep Tayyip Erdoğan as President in 2014, increasingly Islamicized.  By law it’s a secular state, but with 95% of the population Muslim and President Erdoğan seemingly devoted to bringing back religious values, secularism is under siege. One object of religiously-inspired government animus is evolution.

This came clear to me when the late Aykut Kence, perhaps the most famous evolutionist in Turkey, invited me to give a talk at the Middle East Technical University (METU) in Ankara on Darwin Day in 2008. Never have I seen a more enthusiastic group of students, professors, and the public (the lecture I gave against creationism had 1200 attendees!). They loved evolution, and one reason is because every student who loved evolution was pretty much drawn to this school, for evolution wasn’t widely taught. METU is also one of the best and most selective schools in Turkey.  I was inspired, but little did I know that evolution was soon going to be squeezed by the government.

In an eLife article (click on screenshot below), anthropologist N. Ezgi Altınışık, at Hacettepe University (also a very good university in Ankara) recounts the increasing marginalization of evolution in Turkey.

It began in the Seventies when conservatives in the government tried to ban the teaching of evolution in schools. They lost—for a time. Then, slowly, creationism crept into government and schools. 

The infamous Adnan Oktar (aka Harun Yahya) published his Atlas of Creation, a series of glossy and expensive-to-produce books that were sent to nearly every biologist in America. Then in 2009, the 200th anniversary of Darwin’s birth, the government banned an issue of the science magazine Bilim ve Teknik devoted to Darwin:

For me, the breaking point came in 2009. To mark the 200th anniversary of Darwin’s birth, the science magazine Bilim ve Teknik decided to dedicate its front cover and several articles to the famous naturalist. The government banned the issue: the cover was changed, the articles were removed, and the editor-in-chief (one of Turkey’s leading archaeologists) was fired. I still remember my outrage when I heard the news. Bilim ve Teknik is run by TÜBİTAK, a state agency that grants scientific funding. For a long time, it was the only science magazine widely accessible in Turkey. Many people in my generation, myself included, first encountered science through its pages. Massive demonstrations were held across the country in solidarity with the editor. My friends and I visited every professor in our department, encouraging them to join the protest outside of our university. Thousands of young people eagerly attended events that encouraged the defence of the theory of evolution. It was so exciting to see.

That in turn led to organized “protests,” including translating Berkeley’s “Understanding Evolution” website into Turkish, and a series of conferences named after Aykut Kence, who died in 2014. (Tthey continue, and I’ve been invited to participate.)

My own breaking point, at least in fighting the incipient Turkish theocracy, came in 2017, when the government entirely banned the teaching of evolution in secondary schools. A I wrote at the time:

There is no doubt why this is happening: it’s part of the increasing Islamicization of Turkey by the theocratic strongman Erdoğan, who is increasingly demolishing the secular government set up by Kemal Atatürk in favor of Muslim habits and strictures. Besides arresting 50,000 perceived opponents, arrogating more power for himself, imposing more restrictions in alcohol, and reintroducing religious (i.e., Islamic) education in schools, Erdoğan’s now attacking science education.

Since the Qur’an states that humans were created like this:

And certainly did We create man from an extract of clay
Then We place him as a sperm-drop in a firm lodging
Then We made the sperm-drop into a clinging clot, and We made the clot into a lump [of flesh], and we made [from] the lump bones, and We covered the bones with flesh; then We developed him into another creation. So blessed is Allah, the best of creators.

. . . and because many Muslims believe the Qur’an should be read literally, teaching evolution can be seen as anti-Islam, and few Muslim-majority countries teach it in secondary schools. (I once had a Turkish cab driver lecture to me about evolution and how the Qur’an says that humans were created, though he didn’t know I was an evolutionary biologist.)

And so a Turkish student can go all the way through high school and not learn a word about evolution—the central organizing theory of biological diversity. It is banned, and since the alternative is Islamic creationism, that’s the default option. Fortunately, the ban doesn’t apply to public universities—the Turkish government is smart enough to know how that would look.

Altınışık ends on a note of hope, but the best hope for evolution in Turkey is to get rid of Erdoğan and his government, which isn’t a likely prospect. In the meantime, we in the West will continue to visit and help the local scientists fight the good fight. 

As we dream of a better country, we continue to resist. Following meetings at the ministerial level, board members of the Society have managed to get some basic evolutionary concepts reinstated to the curriculum. Volunteers have been organising the Aykut Kence Evolution Conference for over 16 years now, passing it on from one generation of students to the next. It attracts over a thousand attendees every year; when they invited me as speaker, I was amazed by the ambitions of those in attendance. Together with my peers, I still join and organise online and on-site events to promote scientific thinking and enlightenment to students and the public – for example, an online series on human evolution has already received several thousand views and is still getting attention. We also do not limit ourselves to evolutionary biology anymore. As in other parts of the world, anti-vaccine movements rose in Turkey during the pandemic, aided by the recent decline in basic science education. Communicating scientific thinking is more important now than ever.

As a scientist, I believe I have a responsibility towards the people whose taxes funded my education and now fund my research. I am indebted to those who have guided me in the dark as a young student, and to those who cherish the dream of becoming a scientist in Turkey one day. I cannot say that our careers as evolutionary researchers have all been easy, but they may not have been as difficult as one could think. My journey has taught me that when oppressed people stop being alone, they also stop being afraid. To those who need hope and believe in the idea of change, you are not on your own. Our stories will also be your story.

Reader’s wildlife photos

October 24, 2022 • 8:00 am

Today we have another text-and-photo biology lesson from Athayde Tonhasca Júnior, whose text is indented below. Click on the photos to enlarge them.

Just can’t wait to get on the road again

The publication of On the Origin of Species is 1859 is unquestionably one of the most significant episodes in the history of science. Charles Darwin’s and Alfred Russel Wallace’s theory of evolution by natural selection caused such a commotion that one of the book’s other idea didn’t get much attention at the time of publication. For one thing, Darwin dedicated a little over one page to it: the suggestion that evolution is not always the product of a struggle for existence, but sometimes is driven by sexual selection. Or, in Darwin’s own words, by ‘a struggle between the males for possession of the females’.

Darwin was stumped by the fact that natural selection could not explain obvious differences between males (producers of many small reproductive cells or gametes – the sperm) and females (producers of fewer, larger gametes – the eggs) of many creatures. Why should it be that male lions have manes, male deer sport massive antlers, many male birds are endowed with bright and colourful plumage, while their female counterparts have none or subdued versions of those features? Even worse, some characteristics appear to hinder survival and thus cannot be explained by natural selection. Darwin vented his vexation in a letter to American botanist Asa Gray: ‘the sight of a Peacock’s train whenever I gaze at it makes me sick’.

This Indian peafowl‘s (Pavo cristatus) covert feathers (its train) would be tricky if the bird were chased by a tiger in its native Indian forest © Paul Lakin, Wikimedia Commons:

But Darwin’s aggravation didn’t last long, as he elaborated the theory of sexual selection in a subsequent book: The Descent of Man, and Selection in Relation to Sex (1871). In it, he suggested that features in some individuals (males or females) give them advantages over individuals of the same sex solely in respect of reproduction, even though these features could be disadvantageous for survival.  For psychologist Geoffrey Miller, ‘natural selection is about living long enough to reproduce; sexual selection is about convincing others to mate with you’.

[JAC:  A note for readers: many biologists, including me, see sexual selection as a subset of natural selection; both involve repeatable, differential reproduction of gene variants based on the effects they have on their carriers (“vehicles”)]

In The Descent of Man, Darwin wanted to provide evidence that evolutionary principles – including sexual selection – apply to humans. This cartoon from Fun magazine (1872) mocks his ideas. The caption reads: That Troubles Our Monkey Again – female descendant of Marine Ascidian: “Darwin, say what you like about man; but I wish you would leave my emotions alone“:

Sexual selection would work in two ways: through direct competition between males (or less commonly between females), so that contestants become larger and acquire showy ornaments or weaponry, or by female choice (or less commonly by male choice), where mates are chosen based on their perceived quality as parental material. In the case of peacocks, a female would choose a male with the most flamboyant train, which indicates vitality, health, survival skills, and so on. And by showing off his colourful appendage, the male signals to the female that her offspring would have a better chance of survival if he was their daddy.

A figure from The Descent of Man, depicting a male (top) and a female of the suitably named Atlas beetle (Chalcosoma atlas):

For Darwin, morphological differences between males and females (sexual dimorphism) are the expected consequences of sexual selection. Since then, evidence has suggested that selection not based on intrasexual competition or mate choice can also lead to sexual dimorphism. For example, in some birds, differences between males and females in bill morphologies appear to be the result of dissimilar foraging habits (e.g., Tomotani et al., 2022). The current view is that sexual dimorphisms, expressed as differences in appearance, internal morphology and biological functions, are the result of all selective pressures – natural selection and its subset sexual selection – on males and females.

For many invertebrates, females are larger than males, possibly because females need to produce lots of eggs and defend their brood; for birds and mammals, size is biased towards males, a likely result of intra-male competition. L: Female (left) and male banana spiders (Argiope appensa) © Sanba38; R: A male northern elephant seal (Mirounga angustirostris) towering over a female and a pup © Mike Baird, Wikimedia Commons:

 

Sexual dimorphism is one of the most pervasive traits in some plants and many animals, and its consequences are far and wide. For us humans, besides the obvious dissimilarities in size, muscle mass and fat distribution, men and women differ in the risk of contracting some diseases, absorption of drugs, response to therapies and vaccination, and so on. That’s why health researchers are increasingly being required to distinguish the sex of their subjects in clinical trials (e.g., Willingham, 2022).

Naturally, sexual dimorphism is found in bees as well, and it is manifested primarily in their haplodiploid system of sex determination, where unfertilized eggs result in males and fertilized eggs result in females. But bee dimorphism is also expressed in a range of traits such as body size, morphology, coloration, physiology and behaviour, all attributes linked to the roles played by each sex for the species’ survival. Females take care of nest construction and brood provision; in the case of social species such as honey bees (Apis spp.) and bumble bees (Bombus spp.), they maintain and defend the nest. Males on the other hand are driven by one main objective: to seek females and mate with them. So they have no pollen-carrying structures or stingers. This rather narrow life plan has not helped the reputation of males, which have been labelled lazy, free-loading sperm donors. But drones (male honey bees) help with maintaining a hive in good order, and males of many species are better pollinators then their female counterparts.

Hind legs of a male (L) and a female bee, which has a scopa – a cluster of stiff hairs to harvest pollen © Chelsey Ritner, Exotic Bee ID, USDA:

Males of many bee species have another trait, one that could be essential for protecting the species against habitat disturbances: they are hopeless wanderers.

Most bees are solitary (each female builds her own nest) and philopatric, which is the tendency to stay in or return to the site of their origin. Females prefer to nest near the place of their birth because food or good nesting sites could be scarce elsewhere – why take chances with the unknown? This tendency to stay put may result in huge nest aggregations (e.g., the alkali bee, Nomia melanderi). But philopatry induces inbreeding, which doesn’t bode well for the population future. Males, however, who do not have a home or offspring to care for, can fly away in search of a mate outside the old, boring neighbourhood. Sexual attraction is governed by pheromones, and males of some species such as the vernal colletes (Colletes cunicularius) show a preference for scents produced by females from different populations (Vereecken et al., 2007).

A male vernal colletes, looking for love somewhere else © Aiwok, Wikimedia Commons:

The sugarbag bee (Tetragonula carbonaria), a stingless species endemic to Australia, demonstrates males’ dispersing capabilities. They roam an average of 2-3 km from their nests, more than twice the female range, to find a mate; some males cover 20 km, about 30 times the females’ range (Garcia Bulle Bueno et al., 2022). By dispersing over great distances, males are bound to transfer genetic material from one population to another, which is especially important if the species’ habitat has been fragmented by human activity.

A sugarbag bee © Ken Walker, Museum Victoria, Wikimedia Commons.

The role of male dispersal in reducing the effects of inbreeding was inferred from the genetic structure of populations of the oddly named unequal cellophane bee (Colletes inaequalis) in an urban/suburban habitat in New York, USA (López-Uribe et al., 2015). This bee is solitary, but females nest close to each other in aggregations of up to 100 nests/m2. Sampled bees had greater genetic similarity within nest aggregations than bees chosen at random, an expected consequence of philopatry. But there were no signs of inbreeding among the 11 nest aggregations spread over approximately 40 km2, an indication of genetic exchanges between them. And there’s more: within nest aggregations, females were genetically more interrelated than males, a sign of sexually biased migration rates. These DNA analyses elegantly suggest that males are the main arbiters of genetic flow among unequal cellophane bee populations.

A female unequal cellophane bee at the entrance of her nest. B: A nest aggregation © López-Uribe et al., 2015.

Sexual dimorphism has been largely attributed to intra-species competition, often in the form of males fighting each other for a female or to be chosen by one. But sexual dimorphism has a cooperative side: it allows males and females to specialise in what they do best, be it caring for the young, finding food, defending territory, and so on. In the case of bees, males do their bit by gallivanting around. And that results in a reduction in the degree of inbreeding in the species.

Did The Selfish Gene damage public understanding of biology?

October 9, 2022 • 9:30 am

This morning Matthew sent me a tweet by “The Dialectical Biologist” (TDB), which astounded me. I don’t know who TDB is, but he/she identifies as “Biologist. Anti-hereditarian. Lewontin fan.” The anti-hereditarian bit explains some of the criticality in the tweet below, and it’s worth noting that Lewontin himself gave The Selfish Gene a very critical review in Nature in 1977 (free with the legal Unpaywall app).

Here’s the tweet (the second part is the important claim), and two of the six subsequent tweets explaining why TDB sees The Selfish Gene as “the most damaging popular science book of all time.”

I was, of course, Dick Lewontin’s Ph.D. student, and I loved and admired the man. But I have to add that his Marxist politics, which included views of an almost infinite malleability of human behavior, did affect his science, and I think his review of Dawkins’s book is marred by that ideology. If you read Dick’s review, you’ll see that, like TDB above, Lewontin objects to the lack of discussion of genetic drift, and to Dawkins’s supposed claim (one that he didn’t actually make) that every aspect of every organism was installed by natural selection, accompanied by  untestable “adaptive stories” about how it arose. (Lewontin calls this “vulgar Darwinism”.)

In short, Lewontin’s review was an abridged version of his paper with Steve Gould, “The Spandrels of San Marco and the Panglossian paradigm: A  critique of the adaptationist program.” That paper was valuable in correcting the excesses of hyperselectionism, pointing out other reasons besides selection for the appearance of organismal traits and behaviors, and implicitly demanding data instead of fanciful stories for natural-selection explanations. (There are many traits, however, like extreme mimicry, where there is no plausible explanation beyond natural selection on bits of DNA.)

It is misguided to fault Dawkins’s book for not dealing in extenso with genetic drift or the San Marco alternatives. The Selfish Gene is essentially a book about how natural selection really works. It’s not important that it doesn’t define “gene” in the way that TDB wants; in fact, biologists haven’t yet settled on a definition of gene! It’s sufficient, when regarding the phenomenon of natural selection, to define a gene as “a bit of DNA that affects the properties of an organism”. If those properties enhance the reproduction of the carrier (the “vehicle”), then the gene gets overrepresented in the next generation compared to the alternative gene forms (“alleles”). These selected bits of DNA act as if they were selfish, “wanting” to dominate the gene pool. That is a very good metaphor, but one that has been widely misunderstood by people who should be thinking more clearly.

The value in the book lies in its clear explanation of how natural selection acts largely (but not entirely) at the level of the gene, not the organism, the group, the population, or the species; its distinction between “replicators” (bits of DNA subject to natural selection) and “vehicles” (the carriers of replicators whose reproductive output can be affected by those replicators); that “kin selection” is, in essence, nothing really different from natural selection acting on the genes of an individual; and that, contrary to a naive “selfish gene” view, altruism can result from natural selection. Finally, it explains clearly the thesis (earlier adumbrated by G. C. Williams) that “group selection—selection on populations—is not a major source of adaptation in nature. (See Steve Pinker’s wonderful essay on the inefficacy of group selection published ten years ago in Edge.)

The Selfish Gene is the clearest explanation I know of how natural selection works, as well as an exposition of ideas like kin selection that were fairly new at the time of the book’s publication.  It also introduces the idea of “memes”, which I think is a distraction that has led almost nowhere in the understanding of culture, but that is just a throwaway notion at the end of the book. (You can see my critique of the meme framework in a review of Susan Blackmore’s book The Meme Machine that I wrote for Nature; access is free.)

Think of the book as an explanation for the layperson about how natural selection really works, and you’ll recognize its value. As far as “damaging” the popular understanding of science, that is a grossly misguided accusation. By explicating how natural selection really works, explaining some of its variants (like kin selection), and dismissing widespread but largely erroneous ideas about selection on groups, The Selfish Gene did the public an enormous service. While popularity is not always an index of a science book’s quality, in this case it is: many laypeople have written about how they finally understood natural selection after reading it.

I could, in fact, argue that the San Marco paper by Gould and Lewontin was damaging, too, by overly restricting the domain of natural selection and failing to adduce cases where drift or pleiotropy were not sufficient explanations for traits (mimicry is one), so that natural selection was the most parsimonious explanation. (In the latter part of his career, it was hard to get Steve Gould to even admit that selection was important, much less ubiquitous). But “San Marco” was itself valuable in dampening hyper-Darwinism, and in the main was a good contribution to  evolutionary biology. The Selfish Gene was, however, a much better contribution

I asked Matthew, someone who of course knows the ins and outs of evolutionary genetics, if he agreed with TDB’s negative assessment of The Selfish Gene. His reply:

Given I am giving a lecture tomorrow in which I tell 600 students they should all read it, I think not…

When I asked permission to reproduce his quote above, he said “sure” and also me the slide he’s showing his 600 students:

. . .and added this:

FWIW I also show them three views in the levels/units of selection debate (a philosopher who says it has to be genes as they are the only things that are passed down, Dick who says we can’t really know and Hamilton who says it’s complicated and it depends what you look at).
The next section of the lecture deals with social behaviour (hence the final line)
I invite those readers who have read The Selfish Gene to weigh in below with their opinion.

Free BBC broadcast: Three biologists (including Matthew) on their new science books

September 26, 2022 • 9:15 am

I can’t imagine NPR putting on a program like this; it’s long and science-y (without jokes), and intelligent. The moderator is not a radio announcer but a scientist.  What we have are three scientists discussing their new (or upcoming) books about genetics and evolution in a BBC panel moderated by geneticist and science journalist Adam Rutherford. You probably know that Adam himself has written several books on genetics.

The show is 42 minutes of discussion with 8 minutes of live audience questions. Here are the three participants and their new works:

Our own Matthew Cobb, Professor of Zoology at the University of Manchester. Matthew’s talking about his new book on genetic engineering, The Genetic Age: Our Perilous Quest to Edit Life. In the U.S. it’s called As Gods: A Moral History of the Genetic Age (out here November 15). I’ve previously highlighted some positive reviews.

Alison Bashford, Laureate Professor of History at the University of New South Wales and Director of the Laureate Centre for History & Population. Her new book is An Intimate History of Evolution: The Story of the Huxley Family, and deals with both Thomas Henry Huxley and his grandson Aldous Huxley. A positive review of her book is at the Guardian

Deborah Lawlor, a professor of epidemiology at the University of Bristol, is working on a book about the inheritance of diabetes in pregnant women in Bradford of both British and Asian descent. She’s also from Bradford where the show was filmed, and so is a local in two respects.

I recommend listening to it all, but if you want to hear just Matthew, he describes his book beginning at 27:43. But then you’d miss Bashford’s eloquent description of the Huxleys and their contributions.  One fact that I didn’t know was that both T. H. and Aldous Huxley suffered from depression (it was called “melancholia” then), which led Aldous to think about a genetic basis for their condition.

Click below to go to the show’s main page, where you can download the podcast.

And click below to listen to the show. Do it soon if you want to listen, as the BBC doesn’t keep its shows up long.

h/t: Anne

ZeFrank on parasitic birds

September 12, 2022 • 9:15 am

Here’s a great ZeFrank video, “True facts about parasitic birds”, that’s both visually compelling and biologically accurate.  As time passes, ZeFrank seems to get more and more into the biology and evolution of the animals and behaviors he describes and become less involved in being clever. And that’s great, for the videos are now both informative and clever.

This would be a great video to show to a class on evolution or bird biology, and I’ve sent it to reader Bruce Lyon, an evolutionary ornithologist at UC Santa Cruz, as well as and reader and contributor to this site. One of Bruce’s specialities is brood parasitism, and if you have questions for him, put them below (I can’t guarantee he’ll answer, as it’s too early for me to ask him!).

In this 11-minute video, ZeFrank (whoever he is) takes up the issue of “brood parasitism”: the habit of some species of birds to lay their eggs in the nests of birds of other species. (Some also parasitize nests in their own species.) There’s an obvious evolutionary advantage to letting another bird raise and feed your own offspring while you go on and spread your genes by parasitizing another nest.

As ZeFrank shows, this leads to an “arms race” in which the parasitized host is selected to eliminate the eggs dumped in their nests by parasites, while the parasites evolve not clever behavioral strategies and morphological traits to “hide” their eggs and chicks by evolving parasite eggs and chicks to resemble those of the hosts. Even the behavior of parasitic chicks has evolved to resemble the behavior of the offspring that a mother would normally have, deceiving the mom about which chicks are hers. Thus the video instantiates many of the features about evolution that we’ve learned: arms races, convergence (resemblance of parasite eggs and chicks to those of the unrelated parents), the efficacy of natural selection, and the remarkable exactness with which selection can approach an “optimum” (resemblance of parasite chicks and eggs to those of the hosts.)

Be sure to watch the whole thing to see the experimentation that biologists have done on this phenomenon, videos of parasites removing host eggs from the nest (8:00), the feeding a a giant parasite chick—much bigger than the mother!—by a tricked host (9:05), and the “mafia theory” about why some nest parasites will return and destroy a host’s nest if the host has not cared for the parasite’s young (9:50).

h/t: Rick

My interview about evolution with Ray the Producer

September 4, 2022 • 1:35 pm

Yesterday I had an interview with “Ray the Producer” (his YouTube channel, “Allah Who?” is here, and he tends to interview people who are critical of Islam. I was invited on to talk about evolution, a theory that is widely rejected by Muslims, especially those who are Qur’anic literalists. And so the 1.5 hour conversation is about the evidence for evolution and why people reject it. (Ray is an ex-Muslim atheist.)

Here’s the video, and remember that I had about three hours of sleep when I did it yesterday morning. As always, I haven’t listened to it as I cannot abide seeing myself on video. If you can, and want to, here it is for your delectation.