Category: history of science

A celebration of Alfred Russel Wallace

January 9, 2023 • 12:15 pm

Yesterday was Alfred Russel Wallace‘s 200th birthday, an event certainly worth celebrating. And the journal Nature has done so by publishing a few pieces, one of which I’ll highlight here. It’s by my friend Andrew Berry, an instructor of evolutionary biology and a student advisor at Harvard. He’s also edited an anthology of Wallace’s writings.

Andrew’s piece relates a tale he told here years ago, but gives more detail about that incident and about Wallace’s life. I believe the article is free to access, so try clicking below. (If you can’t get it, make a judicious inquiry):

It describes how the ship bearing Wallace and two years’ worth of valuable specimens and collecting notes from South America caught fire and sank in the Atlantic. It was a serious setback, and the misery was compounded by the fact that the men in lifeboats, including a thirsty and sunburned Wallace, were rescued and returned to England. Darwin never underwent such a trial!

But Wallace persisted, and that’s why we know his name and celebrate him. From Berry’s piece:

Stevens had thoughtfully taken out insurance. So Wallace had £200 (US$980 at the time) — a fraction of his collections’ actual value — to cover his costs for a year in London while he tried to salvage what he could from the disaster and make future plans.

He rushed out two books, one a travelogue, the other a more technical account of the palm trees of the Amazon. Neither did well — 250 copies remained unsold a decade later from the travel book’s print run of 750. But he was getting his name out there. Stevens, too, had a done a good job of publicizing Wallace’s discoveries while Wallace had been away.

Perhaps most crucially, the positive response of the UK Royal Geographical Society to his mapping work of the Rio Negro yielded a free steamship ticket to Singapore.

In March 1854, less than 18 months since the Jordeson’s bedraggled arrival at Deal, Wallace departed from Southampton in England for what he would call the “central and controlling incident” of his life.

Eight more years of perilous travel awaited. So, too, did the discoveries of what came to be known as Wallace’s Line (a boundary between the Asian and Australasian biogeographic regions) and of the theory of evolution by natural selection.

The scientific acclaim that greeted Wallace’s return from southeast Asia in 1862 was a just reward both for his contributions and for that phenomenal doggedness — his determination, despite everything, to be a scientist.

Here’s Wallace at 72, a year younger than I am now. Oy, does he look old! But he lived 18 more years.

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:

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.

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

Patrick Matthew: the real inventor of the idea of natural selection?

August 5, 2022 • 9:15 am

Of the several independent assertions that constitute Darwin’s “theory of evolution” in On The Origin of Species, Darwin regarded the idea of natural selection as his most important and original. After all, it alone explained how naturalistic processes could lead to the remarkable adaptations of animals and plants heretofore seen as some of the strongest evidence for God. And although the idea of evolution itself had been broached by others before Darwin, including his own grandfather Erasmus, natural selection seemed to be sui generis.

Well, not entirely.  It was anticipated by several people, including the Scottish polymath James Hutton in 1794. But the most remarkable precursor to the idea of natural selection was published by Scottish horticulturalist and agriculturalist Patrick Matthew (1790-1874) as an appendix to his book On Naval Timber and Arboriculture (1831). Although the book was about how to build ships using wood, and what kind of wood to use, Matthew added a 28-page Appendix. In that Appendix were 29 sentences that laid out what he called “selection by the law of nature”, which bore a striking similarity to the idea made famous by Darwin 28 years later.

You can read Matthew’s appendix at Darwin Online, and some of the statements about his views of natural selection can be seen and discussed in context here, here, and here. ‘

Here are two excerpts from Matthew’s Appendix:

THERE is a law universal in nature, tending to render every reproductive being the best possibly suited to its condition that its kind, or that organized matter, is susceptible of, which appears intended to model the physical and mental or instinctive powers, to their highest perfection, and to continue them so. This law sustains the lion in his strength, the hare in her swiftness, and the fox in his wiles. As Nature, in all her modifications of life, has a power of increase far beyond what is needed to supply the place of what falls by Time’s decay, those individuals who possess not the requisite strength, swiftness, hardihood, or cunning, fall prematurely without reproducing—either a prey to their natural devourers, or sinking under disease, generally induced by want of nourishment, their place being occupied by the more perfect of their own kind, who are pressing on the means of subsistence.

. . . There is more beauty and unity of design in this continual balancing of life to circumstance, and greater conformity to those dispositions of nature which are manifest to us, than in total destruction and new creation. It is improbable that much of this diversification is owing to commixture of species nearly allied, all change by this appears very limited, and confined within the bounds of what is called Species; the progeny of the same parents, under great difference of circumstance, might, in several generations, even become distinct species, incapable of co-reproduction.

The self-regulating adaptive disposition of organized life may, in part, be traced to the extreme fecundity of Nature, who, as before stated, has, in all the varieties of her offspring, a prolific power much beyond (in many cases a thousandfold) what is necessary to fill up the vacancies caused by senile decay. As the field of existence is limited and pre-occupied, it is only the hardier, more robust, better suited to circumstance individuals, who are able to struggle forward to maturity, these inhabiting only the situations to which they have superior adaptation and greater power of occupancy than any other kind; the weaker, less circumstance-suited, being permaturely destroyed. This principle is in constant action, it regulates the colour, the figure, the capacities, and instincts; those individuals of each species, whose colour and covering are best suited to concealment or protection from enemies, or defence from vicissitude and inclemencies of climate, whose figure is best accommodated to health, strength, defence, and support; whose capacities and instincts can best regulate the physical energies to self-advantage according to circumstances—in such immense waste of primary and youthful life, those only come forward to maturity from the strict ordeal by which Nature tests their adaptation to her standard of perfection and fitness to continue their kind by reproduction.

Well yes, that has variation, differential survival, culling of most individuals in a species, speciation, and adaptation—all features of Darwin’s own theory. It’s a remarkable anticipation of Darwin’s ideas.

Does this mean that Matthew deserves credit for the idea of natural selection? Only as an anticipation of Darwin’s far more thorough explication (Darwin, by the way, never read Matthews’ Appendix). Matthew deserves no more credit for natural selection as a popular idea than does Erasmus Darwin for evolution. Matthew’s ideas weren’t adopted, were almost never cited, had no influence in biology, and Matthew never realized until after The Origin was published (and sold out the printing in a single day) that he once had within his grasp The Big Idea that explained the design-like features of nature.

Nevertheless, several people have tried to diminish Darwin’s idea by pointing out that Matthew had it first—and that Darwin plagiarized it. The latest attempt is by Mike Sutton in this book published two months ago (click on image to go to Amazon link):

I haven’t read it, but according to Geoff Cole, a cognitive scientist at the Centre for Brain Science at the University of Essex, who reviewed the book in the latest issue of Evolution (click below for free access), Sutton’s book is a real hit job on Darwin.

The title of Sutton’s book clearly asserts that Darwin took credit for Matthew’s theory, and it’s true that once Patrick Matthew had read The Origin, he argued for his own precedence, even though Darwin had never seen the “incriminating” sentences above.  Sutton also claims that Matthew’s idea had real priority because Naval Timber was cited by others before 1859, but as Cole notes in a very critical but polite review, those citations were almost all to the book itself, not to the ideas in the Appendix.

Cole also notes Sutton’s ridiculous accusations of Darwin’s “plagiarism”:

What is most uncomfortable about Sutton’s thesis is his treatment and personal attack on Darwin. He suggests that Darwin ”was a plagiarist who lied repeatedly” and undertook “deliberate, knowing fraud”. Indeed, “the biggest science fraud in history”; fraud that Darwin supposedly hoped “nobody would notice”. Sutton also expresses suspicion about the chronic illness Darwin was known to suffer; a subject that many historians have written about (e.g., Hayman, 2009). From every single account of Darwin and how he went about his life, these “lies” are the complete opposite of what we know about the man. I have lost count of the number of times I have seen a scholar write that a particular event “is testament to his honesty”. As Browne (1985) stated, “By the time Descent of Man was published in 1871 reviewers were falling over themselves to congratulate Darwin’s “unassailable integrity and candour, and his “wonderful thoroughness and truthfulness” (Browne, 1985, p.257 & 258).

Every serious historian who’s studied Darwin’s life knows that he was neither a plagiarist nor a liar, although he did, understandably, want to preserve credit for his own ideas. After Matthew wrote a claim of his priority in The Gardner’s Chronicle in 1859, Darwin not only published an acknowledgement of Matthew’s precedence in the same magazine, but also inserted this long acknowledgment of Matthew’s work into the 3rd edition of On the Origin of Species:

In 1831 Mr. Patrick Matthew published his work on ‘Naval Timber and Arboriculture,’ in which he gives precisely the same view on the origin of species as that (presently to be alluded to) propounded by Mr. Wallace and myself in the ‘Linnean Journal,’ and as that enlarged on in the present volume. Unfortunately the view was given by Mr. Matthew very briefly in scattered passages in an Appendix to a work on a different subject, so that it remained unnoticed until Mr. Matthew himself drew attention to it in the ‘Gardener’s Chronicle,’ on April 7th, 1860. The differences of Mr. Matthew’s view from mine are not of much importance: he seems to consider that the world was nearly depopulated at successive periods, and then re-stocked; and he gives, as an alternative, that new forms may be generated “without the presence of any mould or germ of former aggregates.” I am not sure that I understand some passages; but it seems that he attributes much influence to the direct action of the conditions of life. He clearly saw, however, the full force of the principle of natural selection. In answer to a letter of mine (published in Gard. Chron., April 13th), fully acknowledging that Mr. Matthew had anticipated me, he with generous candour wrote a letter (Gard. Chron. May 12th) containing the following passage:—”To me the conception of this law of Nature came intuitively as a self-evident fact, almost without an effort of concentrated thought. Mr. Darwin here seems to have more merit in the discovery than I have had; to me it did not appear a discovery. He seems to have worked it out by inductive reason, slowly and with due caution to have made his way synthetically from fact to fact onwards; while with me it was by a general glance at the scheme of Nature that I estimated this select production of species as an à priori recognisable fact—an axiom requiring only to be pointed out to be admitted by unprejudiced minds of sufficient grasp.”

Cole explains patiently why Darwin should get nearly all the credit for the idea of natural selection. A few excerpts from Cole’s excellent review:

Who then should be credited with discovering the process by which evolution occurs? Matthew, Hutton, Maupertuis, Wells? Or anyone else who also chipped in? The answer is simple. Charles Darwin.

. . . A necessary condition of insight is that the knowledge must be reflected upon and placed within the appropriate context. Unless a person fully recognises what they have said, done, or found, no formal insight has occurred. There is no priority.

. . . I suspect Matthew was annoyed with himself, as I was with myself, for not realising the importance of what he had written. That may have been why he dedicated so much of his later efforts on his priority claim. If he had realised he would surely have submitted an academic paper outlining his theory; a paper that was only about the theory. Given fear of religious establishment, this could have initially been anonymously penned. He may have even published a book on the origin of all life forms and how the development of every single species can be explained. He would have also repeatedly used his phrase “the process of natural selection”, a phrase Sutton places great emphasis on, as opposed to the one time he did so in Naval Timber. As it was, there was no paper or book. There was no in-depth development of ideas about evolution and how it relates to divergence, heredity, the geological record, geographic distribution, classification, morphology, and embryology. No lengthy discussion of how there are problems and “difficulties” with his own theory. There was not 30 years of methodical work in which he used his theory to explain aspects of cross-pollination and movement in plants, not to mention work on human psychology, sexual behaviour, and emotions. There were no lengthy and numerous discussions with colleagues about his theory and when he should go public.

In fact, Sutton acts like a creationist, arguing that generations of evolutionary biologists have realized that Matthew should really get credit for the idea; but we have, because of our mindless adulation of Darwin, kept that quiet:

Essentially, Sutton has to explain why generations of evolutionary biologists and the like have never come to the same conclusion as himself. The usual explanation is that we are all involved in a “cover up” (p. 5) or part of the “Darwin Industry”, as Sutton calls it, in which a “loosely affiliated in-group of scientists, historians of science, other writers, publishers, editors, and journals, share a common goal to protect the perception of Charles Darwin as a genius science hero” (p. 10). But how This article is protected by copyright. All rights reserved. about this for an alternative explanation? Those generations of biologists have independently decided that there is nothing to see here, that Darwin should be honoured with discovering evolution. Furthermore, if a few sentences in which natural selection is referenced warrants priority, as Sutton seems to believe, then why pick out Patrick Matthew? Why not his predecessors, Hutton, Wells, or Maupertuis? In fact, shouldn’t Matthew be accused of plagiarism, having failed to acknowledge the fact that his ”own original child” was described at least 30 years before by various others?

Sutton’s book is his latest, in his decade-long, attempt to undermine Darwin’s priority. As all others before, this one will fail.

Of that there’s no doubt. Matthew’s independent musings about natural selection are a remarkable coincidence, but he didn’t make much of them, didn’t examine them further, and certainly didn’t try to integrate them into a grand theory of organic evolution. But judge for yourself: I hope you’ve read The Origin, so just peruse Matthew’s brief discussion and then ask yourself whether Matthew should get the lion’s share of the credit for the idea of natural selection.

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One brief correction of Cole’s fine review: on its first page it describes Darwin as being “the ship’s naturalist” on the voyage of the Beagle. That’s a common misconception, for an “official” naturalist—the ship’s surgeon Robert McCormick—had already been designated. Darwin sailed on the Beagle using his own money, and his position was as both a “self funded naturalist” and also the “captain’s companion”. He was taken aboard largely to provide gentlemanly company for Captain FitzRoy, with whom he dined and conversed. Darwin’s researches and collections during the voyage were done on his own volition and enthusiasm.

Happy Birthday, Rosalind Franklin!

July 25, 2022 • 10:45 am

Note by Jerry: Today would be Rosalind Franklin’s 102nd birthday, and I remembered this excellent assessment of her life and career written for the site by Matthew Cobb exactly two years ago—on Franklin’s 100th birthday. There will be more about Franklin in the book that Matthew’s writing now (a biography of Francis Crick), but I’ll republish this and ask Matthew to correct any mistakes or add anything he wants. It’s good to refresh ourselves about Franklin’s achievements (far more than taking X-rays of DNA), and she does seem to be an object of perennial discussion.

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by Matthew Cobb

Franklin on holiday in Tuscany, 1950.

The chemist and X-ray crystallographer Rosalind Franklin was born 100 years ago today. Although she was never in the public eye in her lifetime, in the last quarter century she has become a figure of renown, with her name attached to a university, a medical school, several buildings and student dorms, lecture theatres, as well as various prestigious medals and fellowships and – most recently – a future Mars Rover and a commemorative UK coin. She died in London, of ovarian cancer, on 16 April 1958.

Franklin’s gravestone, in the Jewish cemetery in Willesden, north London, concludes: ‘Her research and discoveries on viruses remain of lasting benefit to mankind’.

Franklin’s work on RNA viruses, carried out from 1953-58 at Birkbeck College, London – first the tobacco mosaic virus, then, briefly, on the polio virus – was of such significance that her PhD student, Aaron Klug, won the 1982 Nobel Prize for this research. Had she lived, she would have had a good case for winning two Nobel Prizes, one for the virus work, and the other for her contribution to the resolution of the double helix structure of DNA, which she made in 1951 and 1952 at King’s College London.

By any standards, therefore, Franklin was a remarkable scientist whose skill and insights created a great legacy of work. As her Nature obituary put it:

The news of the death of Rosalind Franklin on April 16 came as a shock to many workers in the field of biochemistry and virus studies. It is a special tragedy when a brilliant research worker is cut off at the height of her powers and when exciting new discoveries are expected from her.

She was of international renown, collaborating with leading researchers at Berkeley, Tubingen and Yale. Those scientists valued her because, according to the Nature obituary, her work:

was distinguished by extreme clarity and perfection in everything she undertook. Her photographs are among the most beautiful X-ray photographs of any substance ever taken. Their excellence was the fruit of extreme care in preparation and mounting of the specimens as well as in the taking of the photographs. She did nearly all this work with her own hands. At the same time, she proved to be an admirable director of a research team and inspired those who worked with her to reach the same high standard.

It is striking that few of the commemorations you will see today will present this side of her work.* Instead, they will be focused on her contribution to the most significant biological discovery of the 20th century, the structure of DNA, and in particular the suggestion that James Watson stole a key part of her research—an X-ray photograph taken in 1952—known as photograph 51.

There are two problems with this – firstly, her contribution to science was so much more than ‘simply’ contributing to the structure of DNA, and secondly, in highlighting the supposed role of a single image, we are inadvertently doing her a great injustice.

Most people came to hear about Franklin through Jim Watson’s racy, novelised account of the discovery of the structure of DNA, The Double Helix, which came out in 1968. Written with a verve that contrasts with the plodding prose of his other biographical writings, The Double Helix describes how Maurice Wilkins at King’s showed Watson the famous photograph 51 and, in a flash, Watson realised its significance for the structure of DNA.

This moment, so vivid in the book, is the starting point for the modern emphasis on photograph 51 and on Franklin’s status as a wronged woman (this view is amply justified by Watson’s unsettlingly frank description of his scornful, sexist, contemporary views of Franklin in his book).

In reality, photograph 51 played a key role only in convincing Watson that DNA had a helical structure (that is all that a glance could tell you), which is something that Wilkins had long been convinced of and had been repeatedly argued in discussions in King’s. And in providing a dramatic, Watson-centred hook to the account in the book.

Franklin’s decisive and unwitting contribution to Watson and Crick’s discovery was not a single photo. Indeed, she did not even take photograph 51; it was taken by her PhD student, Raymond Gosling, who had initially been a student of Wilkins. By the end of 1952, Gosling was again supervised by Wilkins, which is why Wilkins had the photo and had every right to show it to Watson. Whether that was wise is another matter.

Instead it was something much more significant: a set of values, established by Franklin on the basis of her detailed studies of these photos, and which were contained in a report by the King’s lab to the Medical Research Council, which provided Watson and above all Crick with the key. This report, including Franklin’s data, was handed to Watson and Crick by members of the Cambridge lab where they worked at the end of 1952.

Franklin was not consulted, but the data were not secret, or private. Indeed, she had presented similar data 15 months earlier at a talk Watson attended, but he did not take notes, and by his own account spent his time musing about her dress sense. But the Cambridge crew could and should have asked her, and were wrong not to. Given her previous (and understandable) complaint to members of Wilkins’ group that they should not interpret her data for her, it is perhaps no surprise that she wasn’t asked – it seems very likely her answer would have been ‘no’.

Once Crick saw the data, he understood their significance in a way that Franklin initially did not do – he had been working on the way that helical molecules diffracted X-rays, so his mind was prepared to understand them in an instant. That encounter of a prepared mind with Franklin’s values, not Watson glancing at photograph 51, was the decisive moment.

By early March 1953, Watson and Crick had come up with the detailed double helix structure, and invited Franklin and Wilkins to come and see it. The King’s duo immediately accepted it as correct – in a way it just had to be true, it was so beautiful. The structure was published in Nature shortly thereafter, as a set of three articles, the other two being from Franklin (including photograph 51) and from Wilkins – they provided the empirical justification (but not proof) for Watson and Crick’s theoretical model.

In a piece of understatement, the Watson and Crick paper acknowledged that ‘We have also been stimulated by a knowledge of the general nature of the unpublished experimental results and ideas of Dr M. H. F. Wilkins, Dr. R. E. Franklin and their co-workers’.

A significant element in the discovery of the double helix was the magic of Watson and Crick’s interaction. It is striking that, unlike them, Franklin did not have anyone she could talk to and argue with about her work, and in particular did not get on with Wilkins (I imagined what might have happened if they had been able to work together in a previous post).

And yet, as she was finishing up at King’s, getting ready to move to Birkbeck, she continued, all on her own, to analyse her data. Her lab books reveal her astonishing solitary progress. By 24 February, using Crick’s method published the year before, she had realised that DNA was a double helix, that the bases on either strand were complementary and interchangeable (A with T, C with G), and above all she realised that, as she put it ‘an infinite variety of nucleotide sequences would be possible to explain the biological specificity of DNA’.

In that final, key respect, she was ahead of Watson and Crick’s first explicit statement of this fundamental aspect of DNA structure, which would not be made for another 3 months (the first Watson and Crick paper had very little on function, referring merely to replication).

Making key contributions to the structure of two important viruses, single-handedly approaching the double helix structure of DNA, those are remarkable contributions by a woman scientist at a time when women were relatively rare in the global scientific community. It is just slightly frustrating that her contribution is ‘reduced’ to DNA, and her role in that discovery is framed in the way Watson self-servingly portrayed it.

But, I suppose, it’s better that Franklin is remembered in a distorted, albeit positive way, than solely through Watson’s portrayal in The Double Helix. The simplicity of the story of ‘she took a photo, Watson stole it, she was robbed’ has an undoubted power, even if it isn’t strictly true. It can be a way for young people to come to grips with the science and the history of science, undoubtedly driven by understandable irritation at Watson’s views, both in his account, and subsequently. For example, it is hard to be grumpy about this rap battle between Franklin and Watson and Crick, written and performed by 7th graders. The historical detail is not precisely right, but still. . .

The iconic power of photograph 51 is probably too cemented to dislodge, and she did, after all, use it in her Nature paper of 1953. So, my irritation at the UK’s commemorative 50p piece is subsumed by the fact that it is a beautiful thing, and better this than nothing:

But remember: it was her data that counted, not that photo. The person who made all the fuss about the photo was Jim Watson, in his novelised account. In that respect, our memory of her is still determined by his account, which should not be taken as historically accurate except where it can be independently verified. Above all, she did so much more than provide the data that were used to discover the double helix. With luck, at her bicentenary a more balanced view will dominant popular culture.

* Two exceptions are this week’s editorial in Nature and an article in the Times Literary Supplement by the historian of science Patricia Fara. Both are excellent brief accounts of Franklin’s life that, as Fara’s title puts it, go ‘beyond the double helix’. Strikingly, both still refer to that photo, rather than the key role of Franklin’s data. That tells you all you need to know about the grip of Watson’s account.

If you want to know more about Franklin, Brenda Maddox’s biography The Dark Lady of DNA is excellent. My book Life’s Greatest Secret (2015) contains a detailed chapter on the double helix and Franklin’s contribution.

Darwin’s modernity in “The Origin”: anticipating the neutral theory and punctuated equilibrium

July 1, 2022 • 9:15 am

Two days ago I wrote a critique of a new article in the Guardian, an article claiming that the modern theory of evolution is obsolete. To support this claim, author Stephen Buranyi asserted  that there are new areas of research—areas like the “neutral theory”, the importance of epigenetics and niche construction, and Gould and Eldredge’s theory of “punctuated equilibrium” that proposed a novel mechanism for a “jerky” fossil record—that have made the modern theory of evolution outdated and, in fact, pretty much obsolete.

Although these ideas were novel and expanded the ambit of evolutionary research, with the neutral theory gaining prominence in the Sixties and punctuated equilibrium in the Seventies and Eighties (culminating with Gould’s big 2002 book, The Structure of Evolutionary Theory), I want to show here that both of these ideas had at least been considered by Darwin.

That is, in the first edition of On the Origin of Species in 1859, Darwin mentioned that some “variations” (he meant what we called “the result of mutations”) could have no effect on survival or reproduction, and therefore whose fate would be determined by the vagaries of chance. This is what the neutral theory, made prominent by Tomoko Ohta and Motoo Kimura, and now by people like Mike Lynch, really asserts, and we have a sophisticated mathematical theory about the fate and effect of neutral mutations.

Further, in The Origin Darwin not only mentions the possibility of a “punctuated” fossil record—in which nothing changes for a long time and then there are bouts of rapid change—but also floats a theory that bears a striking similarity to Gould’s mechanism for that pattern.  Mind you, Darwin’s thoughts on these issues were not the inspiration for either the neutral theory or punctuated equilibrium, but they were already in Darwin’s mind before 1859. This shows that there’s nothing totally new under the evolutionary sun, but also how smart Darwin was.

Here’s my beat-up copy of the first edition of The Origin, which I believe I bought in graduate school. As you see, it’s been well read and mended with tape. I still go through the first edition, though in a different physical book, once every few years.

Over the years, as I reread that copy, I noted on the back cover where Darwin had anticipated modern ideas. Here I’ll talk about just two: “neutral characters” and “punctuated equilibrium”. But you see that there are other “modern” ideas that Darwin discussed in 1859, like allopatric speciation and kin selection. If you have this book, which is probably out of print, you can use the page numbers below to see what he said.

So, on to the two topics.

THE NEUTRAL THEORY

Here’s what the Guardian says about neutral theory:

Doolittle and his allies, such as the computational biologist Arlin Stoltzfus, are descendants of the scientists who challenged the modern synthesis from the late 60s onwards by emphasising the importance of randomness and mutation.

And below are two bits from The Origin about variations that are “neutral”, i.e.m “are of no service or disservice to the species” (he means “individual”). I’ve put Darwin’s musing on neutral variations in bold.

Chapter II (2)

There is one point connected with individual differences, which seems to me extremely perplexing: I refer to those genera which have sometimes been called “protean” or “polymorphic,” in which the species present an inordinate amount of variation; and hardly two naturalists can agree which forms to rank as species and which as varieties. We may instance Rubus, Rosa, and Hieracium amongst plants, several genera of insects, and several genera of Brachiopod shells. In most polymorphic genera some of the species have fixed and definite characters. Genera which are polymorphic in one country seem to be, with some few exceptions, polymorphic in other countries, and likewise, judging from Brachiopod shells, at former periods of time. These facts seem to be very perplexing, for they seem to show that this kind of variability is independent of the conditions of life. I am inclined to suspect that we see in these polymorphic genera variations in points of structure which are of no service or disservice to the species, and which consequently have not been seized on and rendered definite by natural selection, as hereafter will be explained.

Chapter IV

HOW will the struggle for existence, discussed too briefly in the last chapter, act in regard to variation? Can the principle of selection, which we have seen is so potent in the hands of man, apply in nature? I think we shall see that it can act most effectually. Let it be borne in mind in what an endless number of strange peculiarities our domestic productions, and, in a lesser degree, those under nature, vary; and how strong the hereditary tendency is. Under domestication, it may be truly said that the whole organisation becomes in some degree plastic. Let it be borne in mind how infinitely complex and close-fitting are the mutual relations of all organic beings to each other and to their physical conditions of life. Can it, then, be thought improbable, seeing that variations useful to man have undoubtedly occurred, that other variations useful in some bering that many more individuals are born than can possibly survive) that individuals having any advantage, however slight, over others, would have the best chance of surviving and of procreating their kind? On the other hand, we may feel sure that any variation in the least degree injurious would be rigidly destroyed. This preservation of favourable variations and the rejection of injurious variations, I call Natural Selection. Variations neither useful nor injurious would not be affected by natural selection, and would be left a fluctuating element, as perhaps we see in the species called polymorphic.

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PUNCTUATED EQUILIBRIUM

Here’s what the Guardian article says about punctuated equilibrium:

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

But as I emphasized in my critique, Gould and Eldredge’s pattern of a “jerky” fossil record was really supplemented, extended, and publicized by Gould in later writings. The theory got a lot of attention not just because a fossil record of stasis and episodic change (if real and ubiquitous) shows that evolution isn’t as gradual as Darwin or others thought, but because Gould posited a novel, almost non-Darwinian mechanism for that change. If you don’t want to read about this complex mechanism, just skip down to the bold part labeled RESUME READING. 

The mechanism, in short, is this.  Populations of a species become geographically isolated and thus diverge genetically. (This is the first step of the process of speciation that we call “allopatric speciation”, thought by most to be the main way new species arise.) According to Gould, the divergence isn’t really due to natural selection, but to a process of either neutral or maladaptive variants coming to predominate via genetic drift in different populations. (He also posited that many of these variants are “macromutations”: mutations of very large effect, but we’ll leave that erroneous assumption aside.)

Maladaptive mutations are important because they require, to be “fixed” in a group, a small population as well as very strong genetic drift. Such drift can in fact lead maladaptive mutations to predominate in populations, overcoming natural selection that would normally eliminate them. When these mutations predominate—Gould used the example of “Galton’s polyhedron”, a solid that can be pushed and pushed, and suddenly falls on another face that represents a new species—they can then cause reproductive isolation when the new populations hybridizes with others. That reproductive isolation is the most important aspect of speciation.

This is complicated, but take my word for it.

Finally, the new, small population that has new traits and is reproductively isolated from related populations, simply expands and takes over the whole group, a form of “species selection”.  This is not Darwinian “individual or genic selection” because the traits of the expanding population itself (and their underlying genes) are not fitter than the traits of other populations. Instead, the expanding small population has for other reasons either an increased chance of producing new species or a reduced probability of extinction.

This process, said Gould, explains the jerky fossil record. The evolutionary change in the small population isn’t seen in the fossil record because a small population has a small chance of being seen in the fossil record. But when it supplanted all the other populations, it did so rapidly, and that’s why the fossil record is jerky.  Most of the time all the populations of a species are changing in different ways, which average out to “no big change overall” seen in fossils, but when the newly isolated population takes over, then we see big change in the fossil record.

I argued with Gould about this in the literature; one problem is that Gould often denied what he’d said before in print, and never specified a unified, coherent mechanism for punctuated change in a single place. (To see one exchange we had in the literature, go here.)

As I said, there are huge problems with this mechanism, as both the “valley crossing” and “species selection” are very unlikely to happen often, much less often enough to explain ubiquitous jerky patterns. Gould’s mechanistic speculations haven’t stood the test of time, and I haven’t heard them discussed for many years in evolutionary biology (for critiques, see here). Further, there are two other and more parsimonious explanations for a jerky fossil record. The first is that the deposition of sediments itself, which is where we can find fossils, is episodic, with some periods of rapid sedimentation alternating with periods of little sediment formation. Even if evolution were continuous and gradual, this would make it look jerky.

Second—and nobody doubts this, either—natural selection itself varies in strength and direction, and that can cause a jerky patten, too. The classic example is the 1977 drought in the Galápagos islands in  that caused evolutionary change by actually killing the smaller individuals of the medium ground finch by making them unable to eat big seeds. This form of natural selection, documented by Peter and Rosemary Grant and their colleagues, was the subject of the Pulitzer-Prize-winning book The Beak of the Finch (1994) by Jon Weiner.  But after one year the rains came again, the small plants with smaller seeds grew, and finch beak size returned to normal. Here we see an episodic example of natural selection that caused a rapid change (an increase of 10% in beak size in a single generation!) followed by a reversal of that selection.

Even if the fossil record shows an episodic pattern, then, this does not buttress Gould’s convoluted and unlikely mechanism of evolutionary change. People often forget that it is Gould’s novel mechanism, involving macromutations, genetic drift, maladaptive evolution, and species selection, that gave punctuated equilibrium much of its cachet. But evolutionists have no problem with a fossil pattern showing fast evolution during some periods and not much change during others. That does not conflict with the modern theory of evolution.

RESUME READING

I was struck when reading The Origin that Darwin gives not only the “episodic sedimentation” explanation for an uneven fossil record, but also comes close to Gould’s “spread of an isolated population” explanation. Here are two excerpts from the latter part of the book showing this. I’ve put the relevant parts in bold.

Chapter IX

One other consideration is worth notice: with animals and plants that can propagate rapidly and are not highly locomotive, there is reason to suspect, as we have formerly seen, that their varieties are generally at first local; and that such local varieties do not spread widely and supplant their parent-forms until they have been modified and perfected in some considerable degree. According to this view, the chance of discovering in a formation in any one country all the early stages of transition between any two forms, is small, for the successive changes are supposed to have been local or confined to some one spot. Most marine animals have a wide range; and we have seen that with plants it is those which have the widest range, that oftenest present varieties; so that with shells and other marine animals, it is probably those which have had the widest range, far exceeding the limits of the known geological formations of Europe, which have oftenest given rise, first to local varieties and ultimately to new species; and this again would greatly lessen the chance of our being able to trace the stages of transition in any one geological formation.

It should not be forgotten, that at the present day, with perfect specimens for examination, two forms can seldom be connected by intermediate varieties and thus proved to be the same species, until many specimens have been collected from many places; and in the case of fossil species this could rarely be effected by palæontologists. We shall, perhaps, best perceive the improbability of our being enabled to connect species by numerous, fine, intermediate, fossil links, by asking ourselves whether, for instance, geologists at some future period will be able to prove, that our different breeds of cattle, sheep, horses, and dogs have descended from a single stock or from several aboriginal stocks; or, again, whether certain sea-shells inhabiting the shores of North America, which are ranked by some conchologists as distinct species from their European representatives, and by other conchologists as only varieties, are really varieties or are, as it is called, specifically distinct. This could be effected only by the future geologist discovering in a fossil state numerous intermediate gradations; and such success seems to me improbable in the highest degree.

Chapter XIV

Only organic beings of certain classes can be preserved in a fossil condition, at least in any great number. Widely ranging species vary most, and varieties are often at first local,—both causes rendering the discovery of intermediate links less likely. Local varieties will not spread into other and distant regions until they are considerably modified and improved; and when they do spread, if discovered in a geological formation, they will appear as if suddenly created there, and will be simply classed as new species. Most formations have been intermittent in their accumulation; and their duration, I am inclined to believe, has been shorter than the average duration of specific forms. Successive formations are separated from each other by enormous blank intervals of time; for fossiliferous formations, thick enough to resist future degradation, can be accumulated only where much sediment is deposited on the subsiding bed of the sea. During the alternate periods of elevation and of stationary level the record will be blank. During these latter periods there will probably be more variability in the forms of life; during periods of subsidence, more extinction.

With respect to the absence of fossiliferous formations beneath the lowest Silurian strata, I can only recur to the hypothesis given in the ninth chapter. That the geological record is imperfect all will admit; but that it is imperfect to the degree which I require, few will be inclined to admit. If we look to long enough intervals of time, geology plainly declares that all species have changed; and they have changed in the manner which my theory requires, for they have changed slowly and in a graduated manner. We clearly see this in the fossil remains from consecutive formations invariably being much more closely related to each other, than are the fossils from formations distant from each other in time.

In the last paragraph Darwin hews to the well-known “gradualism”, to which he admitted no exception. The jerky patterns in the fossil record he ascribes to either an incomplete fossil record or to straight natural selection, with the spread throughout a species of adaptive variants arising in isolated populations.

As I said, these musings didn’t have any influence on Kimura or Gould, but they do show that Darwin was already thinking about neutral variations and about a punctuated fossil record well before he published this stuff in 1859.

The breadth and originality of Darwin’s thinking is one reason why everyone should read The Origin,  even if its Victorian prose is sometimes daunting. (The chapter on “hybridism”, for example, is a real slog.) But I hope I don’t sound pretentious if I say that a person cannot be considered properly educated if they haven’t read Darwin’s great work—ideally the first edition so you can get a full flavor of how revolutionary it was.

Amen.