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Showing posts with label Darwin skeptic. Show all posts
Showing posts with label Darwin skeptic. Show all posts

Saturday, 21 December 2024

On darwinian apologists sleight of hand

 Evolutionary Flimflam: Watch Out for These Common Parlor Tricks in Science Reporting


I suspect the average person comes to accept modern evolutionary theory, not through a series of careful arguments, but through a near-constant drip of pro-evolution propaganda. The propaganda comes in many forms and from many directions. Here I want to focus on just one source, popular news stories about evolution, and specifically on a couple of parlor tricks often embedded in these articles.

Bait-and-Switch

Probably the most common trick begins with a news headline or lead sentence promising a new discovery of evolution in action. The article then highlights an actual, observed species changing over time. But the example it cites is mere microevolution, such as a change in fur color or minor changes in beak size or leg length. 

That won’t do. If Charles Darwin had argued that nature can produce modest variations in existing species, the collective response would have been, now tell us something we don’t know. Evolutionary theory needs to provide evidence of its distinctive claim, namely, that purely natural mechanisms can and do produce major innovations — something like the first wings, the first eyes, new molecular biological machines, or novel animal body plans. 

A recent example of this bait-and-switch begins with the headline, “Long-term Lizard Study Challenges the Rules of Evolutionary Biology.”1 The headline gives the impression that maybe the lizards in the study, refusing to play by the restrictive rules of standard evolutionary theory, hauled off and evolved in a much more daring way than conventional thinking had allowed. But then we learn that the study’s big finding helps explain cases where evolution doesn’t generate anything impressive — that is, cases of stasis, where a species remains largely unchanged for millions of years. 

Hmm, that sounds like the opposite of impressive evolutionary daring-do, doesn’t it? 

Troubled by this inconsistency but undaunted, we read on and are soon informed that the researchers have solved a big evolutionary conundrum. The news story invites us to wonder how there could be so many cases of stasis in the history of life when we see evolution doing amazing stuff right before our eyes all the time. The article doesn’t mention any of these amazing broad-daylight transformations. Instead it informs us that the study found that the lizards varied in minor ways (e.g., longer or shorter legs) and that the changes, rather than accumulating into something dramatically novel, canceled each other out. Voilà — an explanation for stasis.

That’s it. That’s the study’s big finding. No macroevolution. Just the observation of what was the common view before Darwin’s theory of evolution — that healthy members of a species can vary a bit, but only within strict limits.

To sum up the parlor trick: Promise to demonstrate bigtime evolution. Demonstrate minor changes and hope the audience doesn’t notice the difference. 

An Audacious Use of Stasis

A particularly brazen variation on this bait-and-switch appears in an article out of Ireland. The lead sentence announces, “Palaeontologists at UCC have discovered X-ray evidence of proteins in fossil feathers that sheds new light on feather evolution.”2 What is the discovery? That, contra expectations, the protein in question has not evolved for tens of millions of years. In other words, the findings suggest more stasis in the history of life and diminished evidence for evolution. 

So now it’s not microevolution (minor changes) standing in for macroevolution (big innovations). It’s a discovery of stasis (basically, no change) standing in for macroevolution. Laughable if you’re paying attention, but if you’re just skimming headlines and articles, well, the word “evolution” appears three times, and the scientific paper being reported on appeared in Nature Ecology & Evolution. Sounds like a whole lotta evolution goin’ on. 

Drip, drip, drip. So works the propaganda.

Dazzle and Distract

A second parlor trick used to the same end is a tad harder to spot. It involves reporting on a discovery that sheds light on how some complex biological process works, and then promises that the finding gives us important insights into how the process evolved. How so? The teaser turns out to be yet another of evolutionary theory’s many promissory notes, one you will grow old waiting on for payment.

We shouldn’t take the promise on faith, since it’s far from automatic that discovering how a given biological mechanism works will help biologists understand how the process evolved. Certainly it wouldn’t if evolution did not actually generate the mechanism in question. But even if we grant for the sake of argument that the biological process did evolve, and did so through blind material forces, it’s perfectly possible that gaining a better understanding of how a mechanism works would in no way reveal how the process it’s embedded in evolved. 

Nor is it enough to show that the newly understood mechanism is useful to the biological system it’s a part of. Yes, natural selection tends to favor the useful over the useless in the evolutionary process, but that doesn’t allow evolution’s blind process of gradual change to magically look ahead so as to bring together various parts to assemble an intricate new mechanism. The act of looking ahead (foresight) and planning for a distant goal is the exclusive domain of minds. Mindless evolution, lacking this capacity, requires a series of small, functional, random mutations (blind baby steps) in order to evolve, say, the first bat sonar or the first air-breathing animals. The evolutionist should detail a plausible stepwise path of this sort, and then we can talk.

This second parlor trick, to summarize, runs like this: (1) Highlight a fresh insight into how a biological mechanism works. (2) Tout the discovery as shedding important light on how a system or process evolved. (3) Don’t actually demonstrate #2, but instead dazzle and distract the reader with the challenging technical details of the discovery highlighted in #1.

The Curious Case of TCOF1
An example of this second parlor trick appears in a Science Daily news piece titled, “Study Explains How Part of the Nucleolus Evolved.”3 What did the researchers learn? “Biologists discovered that a scaffolding protein called TCOF1 is responsible for the formation of a biomolecular condensate called the fibrillar center, which forms within the cell nucleolus.”

We could challenge the phrasing there. The language makes it sound like the scaffolding protein single-handedly forms the fibrillar center, when we can be sure the protein is just one crucial player in a process involving many other factors without which we would have no fibrillar center. But set that quibble aside. 

The article further informs us that “biomolecular condensates perform many critical functions” in cells. Then we encounter a refreshing note of humility: “It is not well understood how proteins and other biomolecules come together to form these assemblies within cells.” Then an overdue qualifier: “The findings could help to explain a major evolutionary shift, which took place around 300 million years ago, in how the nucleolus is organized.” 

So we’ve gone from “Study Explains” in the headline to “The findings could help to explain.” 

Then another concession: “Biologists do not yet fully understand why this shift happened.” Although a welcome injection of honesty, the sentence also subtly implies that biologists mostly understand why the shift happened, just not fully. But the article doesn’t give us the mostly. It just implies that the understanding is out there and leaves us to accept the implicit claim on faith. 

What the article does explain is quite different from what the headline promised:

“If you look across the tree of life, the basic structure and function of the ribosome has remained quite static; however, the process of making it keeps evolving. Our hypothesis for why this process keeps evolving is that it might make it easier to assemble ribosomes by compartmentalizing the different biochemical reactions,” says Eliezer Calo, an associate professor of biology at MIT and the senior author of the study.

So, the ribosome presents another striking case of stasis, but at least the process of how it is made keeps evolving, or so we are told. But how do they know the process evolved, and evolved through mindless material mechanisms, as the theory of evolution holds? Just showing that nature has more than one way of making ribosomes doesn’t demonstrate that these methods evolved one from another, or from a common ancestral method. After all, the various methods might each have been separately designed, as the various methods for assembling cars were separately designed.

What of the researcher’s specific evolutionary hypothesis summarized in the block quote above? It’s at best an extremely partial explanation. He is saying that the assembly method evolved because the innovation might make the assembly go smoother. In other words, the explanation of how it evolved boils down to pointing out a possible functional improvement in the method. But usefulness is only a necessary condition of evolution by natural selection; it’s far from a sufficient condition, just as being able to dribble a ball is a necessary condition of being an NBA basketball player, but far from a sufficient one.

If the researchers had identified a definite functional improvement as an explanation for how the assembly method evolved, that would be weak tea; but they didn’t even do that. They only identified a possible functional improvement. And from all this we get the breathless headline, “Study Explains How Part of the Nucleolus Evolved.”

And so it goes. Drip, drip, drip.

Notes

Catherine Barzler, “Long-term Lizard Study Challenges the Rules of Evolutionary Biology,” Phys.org (October 9, 2023). 
“Dinosaur Feathers Reveal Traces of Ancient Proteins,” University College Cork, Ireland (September 22, 2023).
“Study Explains How Part of the Nucleolus Evolved,” Science Daily (August 15, 2023).

Tuesday, 17 December 2024

Darwinism and teleology: Friends/enemies/frenemies?

 Did Darwin Banish Teleology from Nature or Not?


I have been reviewing a new collection from Cambridge University Press, Darwin Mythology: Debunking Myths, Correcting Falsehoods. (See my earlier posts here and here.) James G. Lennox opens his essay about Darwin’s views on teleology with Friedrich Engels’s statement in a letter to Karl Marx. Engels exulted that Darwin had demolished teleology. This is a view that is commonplace among many Darwinian biologists, as well as historians. Lennox, however, calls it a myth that Darwin banished teleology from nature.


Lennox defines teleology thus: “A teleological explanation is one in which some property, process or entity is said to exist or be taking place for the sake of a certain result or consequence.” In the course of the essay Lennox points out that when discussing organisms’ adaptations, Darwin often used the language of teleology: “final cause,” “contrivances for this end,” etc.

Lennox also correctly points out that Darwin’s teleology differed from that of Harvard biologist Asa Gray, who argued that teleology implied natural theology. Darwin completely rejected natural theology. Lennox is right that this makes Darwin’s and Gray’s teleology different.

The problem with Lennox’s analysis is twofold: 1) Darwin recognized that his use of teleological language could be problematic; and 2) the kind of teleology that Lennox claims Darwin embraced is trivial compared to the kind of teleology he rejected.

Darwin’s Teleological Language
To be sure, Darwin used teleological language when discussing organisms’ adaptations. Lennox quotes from an 1862 essay, where Darwin wrote that “the final cause of all this mimicry” among butterflies is evading predation. Lennox then states, “It is this valuable consequence of mimicry that explains its selective advantage — that is the end achieved by mimicry.” (p. 191) Thus, Darwin recognized that adaptations had purposes. For instance, the eye has a purpose — it is for seeing.

Sometimes Darwin’s contemporaries criticized him for using teleological language. In 1877 Darwin responded to Alphonse de Candolle’s critique:

There is much justice in your criticisms on my use of the terms object, end, purpose; but those who believe that organs have been gradually modified by natural selection for a special purpose, may I think use the above terms correctly though no conscious being has intervened. I have found much difficulty in my occasional attempts to avoid these terms; but I might perhaps have always spok[en] of a beneficial or serviceable effect.1

Darwin’s claim here that there was some justice in the critique, as well as his confession that he sometimes tried to avoid teleological terms, suggests that Darwin was not entirely comfortable using teleological language. However, he defends the use of teleological language nonetheless, because he believed that adaptations did serve a purpose — helping an organism survive and reproduce in the struggle for existence. In light of this, perhaps Lennox has a point.

The Teleology Darwin Did Banish from Nature

However, Lennox seems to miss the point that, even though Darwin admitted that adaptations served a purpose, he vociferously denied that the evolutionary process was teleological. When Engels and most scholars insist that Darwin banished teleology from nature, they are denying that evolution is a teleological process. They are not denying that specific organs of animals and plants serve specific purposes.

Darwin often stressed that evolution on the whole was non-teleological. In an 1881 letter to William Graham, Darwin stated that his primary disagreement with Graham “is that the existence of so-called natural laws implies purpose. I cannot see this.”2 Both here and in many other writings Darwin explicitly denied the existence of any over-arching purpose for organisms.

In 1861 Darwin wrote to Lyell a letter where he denied that adaptations had originated for a purpose: “No doubt these [i.e., variations] are all caused by some unknown law, but I cannot believe they were ordained for any purpose; & if not so ordained under domesticity, I can see no reason to believe that they were ordained in a state of nature.”3 Since variations are the source of evolutionary change, Darwin was hereby denying that evolution had any goal toward which it was moving.

Darwin often used the term “chance” to describe variations in nature, because he did not believe variations arose for any purpose or toward any goal. This is why Darwinian evolution is a non-teleological process. Thus, despite Lennox’s arguments, it still makes sense to say that Darwin banished teleology from the evolutionary process, even if biological adaptations do serve various purposes.

Notes

Darwin to Alphonse de Candolle, August 3, 1877, Darwin Correspondence Project, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-11092.xml&query=purpose.
Darwin to William Graham, July 3, 1881, Darwin Correspondence Project, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-13230.xml&query=purpose.
Darwin to Charles Lyell, August 13, 1861, Darwin Correspondence Project, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-3230.xml&query=purpose.

Saturday, 14 December 2024

On more Darwinian mythmaking and mythbusting.

 Is It a Myth That Darwin Rejected Design?


In the new book I’m reviewing here, Darwin Mythology: Debunking Myths, Correcting Falsehoods, the actual title of Michael Ruse’s chapter is “Myth 4: That Darwin Always Rejected the Argument from Design in Nature and Developed His Own Theory to Replace It.” (See my first post in this review series here.) I have never heard anyone claim that Darwin always rejected the argument from design, because before he came to believe in evolution in the late 1830s, he found William Paley’s natural theology — which was based on the argument from design — convincing. Many scholars — myself included — believe that as Darwin formulated his theory in the late 1830s, he rejected the argument from design and used natural selection as a way to explain how things could look designed without actually being designed. Ruse disagrees, claiming that Darwin still embraced design when he wrote The Origin of Species in 1859.

In his essay, the late Professor Ruse correctly explains that Darwin rejected theism and embraced deism in the 1830s, and he continued using deistic language in The Origin of Species. Deism is the idea that God created the cosmos and its natural laws, but thereafter did not intervene with miraculous events. Sometime after 1859 and before 1870, Ruse informs us, Darwin gave up on deism and embraced an agnostic position. 

So Far, So Good

However, Ruse then makes the controversial — and misguided — claim that throughout this deistic phase of Darwin’s life — including during his writing of The Origin of Species — he continued to believe in the argument from design in nature. Ruse is correct that in Origin and in his correspondence, Darwin continued to admit that the universe and natural laws seem designed, and some kind of deistic God probably created those laws. However, Ruse then confuses this notion that the cosmos as a whole is designed with the idea that biological organisms exhibit design.

Strangely, Ruse even quotes from an 1860 letter that Darwin wrote to Harvard biologist Asa Gray. Darwin continually debated with Gray about the argument from design, with Darwin taking the position that organisms are not designed. Here is the passage Ruse quotes:

With respect to the theological view of the question; this is always painful to me. — I am bewildered. — I had no intention to write atheistically. But I own that I cannot see, as plainly as others do & as I sh[oul]d wish to do, evidence of design & beneficence on all sides of us. There seems to me too much misery in the world. I cannot persuade myself that a beneficent & omnipotent God would have designedly created the Ichneumonidae with the express intention of their feeding within the living bodies of caterpillars, or that a cat should play with mice. Not believing this, I see no necessity in the belief that the eye was expressly designed.

This is a clear expression of Darwin rejecting the design of organisms and their adaptations. Ruse, however, will not admit this, but instead inexplicably states, “The argument from design interpreted in a deistic manner seems still to have legs.” Really? Where? Darwin has just stated that he “cannot see . . . evidence of design,” and he denied that cats or eyes are designed.

An Untenable Position

Ruse’s position is simply untenable, especially if one reads even more of Darwin’s correspondence in the year or two after publishing Origin, where he directly confronted the issue of design. 

In a July 1861 letter Darwin explained clearly his view of design:

The mind refuses to look at this universe, being what it is, without having been designed; yet, where one would most expect design, viz. in the structure of a sentient being, the more I think on the subject, the less I can see proof of design. Asa Gray and some others look at each variation, or at least at each beneficial variation (which A. Gray would compare with the rain drops which do not fall on the sea, but on to the land to fertilize it) as having been providentially designed. Yet when I ask him whether he looks at each variation in the rock-pigeon, by which man has made by accumulation a pouter or fantail pigeon, as providentially designed for man’s amusement, he does not know what to answer; and if he, or any one, admits these variations are accidental, as far as purpose is concerned (of course not accidental as to their cause or origin); then I can see no reason why he should rank the accumulated variations by which the beautifully adapted woodpecker has been formed, as providentially designed.1

So, while Darwin may have had a vague idea about the cosmos being designed, he clearly rejected the notion that biological organisms exhibited design.

Correspondence with Charles Lyell

Another example is an 1861 letter to his friend Charles Lyell, the founder of uniformitarian geology. Darwin discussed his disagreement with Gray, who believed that God guided variations. Darwin wrote:

The view that each variation has been providentially arranged seems to me to make natural selection entirely superfluous, & indeed takes whole case of appearance of new species out of the range of science. . . . It seems to me that variations in the domestic & wild conditions are due to unknown causes & are without purpose & in so far accidental; & that they become purposeful only when they are selected by man for his pleasure, or by what we call natural selection in the struggle for life & under changing conditions.2

In this letter Darwin maintained that natural selection could explain purpose or design in organisms, thus rendering divine providence unnecessary.

As many scholars have argued, Darwin’s rejection of the argument from design preceded his publication of Origin by many years; it was not an afterthought.

Rather Awkward

Interestingly, at the close of his essay, Ruse puts forward an argument that is rather awkward in light of his overall point. He claims that Darwin — after writing Origin — “came to see that the variations produced by a deistic God are no less directed than the variations produced by a theistic God.” Ruse then states, “Natural selection makes guided variations unnecessary. No need to assume a Designer. Hence, even as it keeps the major premise, that organisms are as-if designed, natural selection destroys the argument from design.” (p. 55) Ruse never explains why he thinks Darwin did not understand this point already in the late 1830s as he developed his theory, as many other scholars have insisted.

In sum, Ruse admits that natural selection eliminates the need for design. However, he wrongly argues that Darwin did not fully understand that until after writing Origin.

Notes

Charles Darwin to Frances Julia Wedgwood, July 11, 1861, Darwin Correspondence Project,https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-3206.xml&query=design.
Charles Darwin to Charles Lyell, August 1, 1861, Darwin Correspondence Project, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-3223.xml&query=purpose

Wednesday, 11 December 2024

On Darwinian mythmaking and mythbusting.

 A New Scholarly Book Trying to Debunk Myths about Charles Darwin and His Theory


In a new book published by Cambridge University Press, Darwin Mythology: Debunking Myths, Correcting Falsehoods, an array of prominent Darwin scholars attempt to dismantle 24 myths about Darwin and his theory. Many of these essays are excellent examples of historians setting the record straight. However, while myth-busting is a venerable pursuit for historians, caution must be exercised, especially when dealing with ideologically loaded subjects. Indeed, ironically, in a few cases in this volume, which I will discuss in subsequent posts, the debunkers need to be debunked themselves, because instead of correcting falsehoods, they end up creating or perpetuating falsehoods.

Problems with “Mythology”

Indeed, the whole notion of mythology can at times be problematic, because some scholars brand as “myth” interpretations of other scholars with whom they disagree. For example, James G. Lennox, in his chapter on Darwin and teleology (which I will discuss in a subsequent post), informs us that the Darwinian biologist Michael Ghiselin has dubbed as myth the view that Darwin’s theory included teleology. Lennox states, “In this chapter, then, my aim is to show that what Michael Ghiselin claims to be a myth is in fact reality, and that his assertion that Darwin rid biology of teleology is itself a myth.” (p. 183) So here we have two scholars insisting that the other one is embracing a myth.

A related problem is that in some cases, the scholars in this volume disagree among themselves on what is mythical. For example, David Depew in his essay claims that in addition to natural selection, Darwin also believed in group selection. (p. 177) In his essay on Darwin and race, Erik L. Peterson seems to agree, strongly implying that Darwin believed in group selection. (p. 255) The late Michael Ruse, however, in trying to distance Darwin from Alfred Russel Wallace, claims rather emphatically that Darwin rejected group selection. (pp. 133-34)

So, Which Is the Myth?

On this particular issue of group selection, it seems to me that Ruse is the one perpetuating a misconception about Darwin. Ruse uses rather twisted logic to maintain his position. After quoting a passage in Descent of Man where Darwin discusses tribes competing with other tribes (which is group selection), Ruse makes the bizarre claim that this is not really group selection. Why not? Well, Ruse informs us that right after this discussion of tribes competing, Darwin promoted what we call today “reciprocal altruism.” Therefore, Ruse oddly asserts, Darwin could not be promoting the idea of group selection. (I should note that Ruse is wrong about the placement of this passage, as it actually comes three pages earlier than the one about the tribes, but this is a minor point). Ruse’s logic is fallacious, because group selection and reciprocal altruism are not contradictory. Darwin believed them both. No wonder Depew and Peterson disagree with Ruse, as do a host of other Darwin scholars.

Before I critique the other essays that are problematic, let me draw attention to some of the myths about Darwin that this volume properly addresses. John Hedley Brooke refutes the myth that the biologist Thomas Henry Huxley demolished Anglican Bishop Samuel Wilberforce at their famous 1860 debate before the British Association for the Advancement of Science. It seems that the debate (or discussion) was more of a toss-up. I was surprised to learn from Brooke’s essay that one scientist who had embraced Darwinism before this event actually abandoned Darwinism as a result of the discussion that day. (p. 151)

White Supremacy and Genocide

An interesting essay by Erik L. Peterson refutes the myth that Darwin believed in racial equality. Peterson acknowledges that Darwin hated slavery, but shows that it was not because he believed in racial equality. Both in Descent of Man and in his correspondence Darwin not only clearly expressed belief in the racial superiority of Europeans, but he insisted that the Europeans’ triumph in the racial struggle for existence — which would result in the racial extermination of allegedly inferior races — would bring evolutionary advance to the human species. In an 1860 letter to Lyell, Darwin stated, “White man is ‘improving off the face of the earth’ even races nearly his equal.” Right after quoting this, Peterson comments, “Here again, we might find jarring Darwin’s cavalier references to white supremacy and genocide as supportive of his overall theory.” (p. 254)

In another essay Richard W. Burkhardt Jr. counters the widespread idea that Darwin rejected Lamarck’s ideas about use and disuse and the inheritance of acquired characteristics. To be sure, Burkhardt explains that Darwin stressed the primacy of natural selection and considered Lamarckian mechanisms secondary. However, Darwin did not dismiss them outright, as some later Darwinians, such as the German biologist August Weismann, did.

John Van Whye makes a strong case against the claim that Darwin delayed publication of The Origin of Species for twenty years, allegedly because he was afraid to make his views public. Van Whye shows that Darwin divulged his theory to many of his contemporaries in his correspondence. None of Darwin’s family or contemporaries ever claimed that Darwin delayed publishing his theory. Indeed, the idea that he delayed only arose in the mid 20th century. During those twenty years between discovering his theory and publishing it, Darwin was studying and doing research to buttress and refine his theory.

Just a Sampling

This is just a sampling of the many interesting and useful essays in this work. However, as I indicated, some of the essays are problematic, and I will address a few of these in the coming days.

Saturday, 30 November 2024

The "equilbrium" in "punctuated equilibrium" ?

Fossil Friday: Evolutionary Stasis in Beetles


This Fossil Friday features the living ground beetle genus Loricera, which has recently been recovered as fossil adults and larvae from mid-Cretaceous Burmese amber. The genus belongs to the ground beetle family Carabidae and features in adults as well as the larval stage specially modified antennae and mouth parts for predation on springtails (Collembola) in leaf litter. Spiny hairs at the base of the antennae and the maxillae serve as a kind of catching cage for their springtail prey. This complex adaptation has now turned out to be much more ancient than expected.

In two recent papers Li et al. (2024a, 2024b) described adult and larval Loricera beetles from the mid-Cretaceous Kachin amber (Burmite) of Myanmar, which has been radiometrically dated to an age of 99 million years. These fossil beetles are basically indistinguishable from the various living species of the genus Loricera and have identical anatomical features of adults and larvae. This means that this beetle with its unique adaptations existed in unchanged form since at least about 100 million years and survived the mass extinction at the end of the Cretaceous period.

The Crucial Point

A popular science article in Wired (Kahil 2024) freely admits that “the Loricera beetle’s survival story challenges conventional notions of evolution” and exhibits “a remarkable consistency in an ever-changing world.” This is indeed the crucial point, because such striking cases of stasis are commonly explained away by evolutionary biologists as due to stabilizing selection in a stable environment of their ecological niche. However, this explanation simply is not plausible over hundreds of millions of years with changing habitats, changing climate, changing biota, and even mass extinction events of apocalyptic dimensions. The press release (NIGPAS 2024) reporting the new discovery acknowledges that “the K/Pg mass extinction triggered one of the most profound biodiversity reorganizations in geological history,” but still “the study suggests that both springtails and their predators have exhibited significant evolutionary stasis, both in terms of individual species morphology and community structure.”

Compare this with the evolutionist’s claim that pig-like mammals similar to Indohyus and Pakicetus changed into fully marine dolphin-like whales such as Dorudon and Basilosaurus in just 4 to 8 million years. Natural selection is the great magician in evolutionary fantasy land, where it explains rapid change in explosive radiations as well as no change at all over eons in so-called “living fossils.” However, a theory that is always perfectly consistent with any possible outcome is not explaining anything, but rather is as dubious as Freudian psychoanalysis or astrology, with their vague predictions that always fit. And every fit is sold to the gullible public as a successful corroboration of the theory, which is why people still believe in astrology and — for what it’s worth — in unguided evolution through natural selection acting on random mutations. It is time to call neo-Darwinism out for what it indubitably is: a pseudoscience, which is nurtured, promoted, and fiercely defended by a gigantic industry in mainstream academia that depends on it!

References

Kahil N 2024. This black beetle is a survivor of the dinosaur extinction. Wired November 4, 2024. https://wired.me/science/this-black-beetle-is-a-survivor-of-the-dinosaur-extinction/
Li Y-D, Tihelka E, Engel MS, Huang & Cai C 2024a. Specialized springtail predation by Loricera beetles: An example of evolutionary stasis across the K-Pg extinction. The Innovation 5(3): 100601, 1–2. DOI: https://doi.org/10.1016/j.xinn.2024.100601
Li Y-D, Tihelka E, Engel MS, Xia F-Y, Huang D-Y, Zippel A, Tun KL, Haug GT, Müller P & Cai C-Y 2024b. Description of adult and larval Loricera from mid-Cretaceous Kachin amber (Coleoptera: Carabidae). Palaeoentomology 7(2), 265–276. DOI: https://doi.org/10.11646/palaeoentomology.7.2.10
NIGPAS 2024. Cretaceous Amber Reveals the Stability of Beetle-Specialized Predation. NIGPAS Newsroom September 25, http://english.nigpas.cas.cn/new/hs/rp/202409/t20240925_690552.html

Saturday, 23 November 2024

Those time travelling birds again?

 Fossil Friday: New Fossil Stem Bird Is Surprisingly Modern


This Fossil Friday features the bird Navaornis hestiae from the Late Cretaceous Adamantina Formation of southeastern Brazil, which is dated to an age of about 80 million years. This fossil was attributed to an extinct group called Enantiornithes, which thrived in many species around the globe in the Cretaceous period. The new taxon was just described this month by Chiappe et al. (2024) in the journal Nature. The discovery of this perfectly preserved fossil bird turned out be a kind of puzzle for evolutionary biologists, who study the history of bird origins.

The beautiful fossil even preserved detailed structures of the brain that could be studied with high-resolution CT scanning. A morphometrical analysis of the geometry of the brain placed Navaornis about midway between Archaeopteryx and modern birds. This is certainly interesting and arguably fits with the common evolutionary scenario. The authors of the new study say that “Navaornis exhibits a brain morphology intermediate between Archaeopteryx and crown birds along the main axis of endocranial shape variation” and thus “the morphology of the endocast of Navaornis shows an intermediate stage in the evolutionary history of the unique avian brain.” A news report in SciNews (News Staff 2024) quotes one of the authors with a comment that “the brain structure of Navaornis hestiae is almost exactly intermediate between Archaeopteryx and modern birds — it was one of these moments in which the missing piece fits absolutely perfectly.” Such a gem of course directly made it into the headline of the article that is titled ”80-Million-Year-Old Enantiornithine Fossil Fills Gap between Archaeopteryx and Modern Birds”.

So Far So Good

But there is a little complication. Even though entantiornithine birds are considered as stem birds because of several relatively “primitive” traits in their anatomy, the new species shows a remarkable similarity to modern birds that was quite unexpected for the scientists. The authors describe that the “cranial geometry of Navaornis shows an unprecedented degree of similarity between crown birds and enantiornithines” and note that “despite an overall geometry quantitatively indistinguishable from crown birds, the skull of Navaornis retains numerous plesiomorphies.” They admit this “implies that the origins of these ‘advanced’ traits often associated with crown birds either predated the origin of Ornithothoraces or evolved convergently among both Enantiornithes and crownward Euornithes.” They conclude as follows:

This degree of geometric convergence between Enantiornithes and crown birds suggests that developmental constraints responsible for canalizing the general shape of the bird skull may have been present throughout much of avian evolutionary history, predating both the phylogenetic divergence between Enantiornithes and Euornithes more than 130 million years ago as well as the evolutionary acquisition of several apomorphic characteristics of crown bird skull and brain morphology. The exceptionally well-preserved skull of Navaornis emphasizes the necessity of hitherto elusive undistorted Mesozoic bird skulls for illuminating the complex sequence by which the unique brains and skulls of modern birds arose.

Note the Crucial Word

Convergence means similarity not based on common descent, “may have been” means they have no clue, and “complex sequence” means that the data are not what they expected to find. Prior to this discovery none of the experts would have predicted such a modern skull in a “primitive” stem bird, but after the fact evolutionary biologists are always quick to offer a fancy just-so-story that reconciles the evidence with the theory.

It is quite remarkable that popular science reports such as an article in New Scientist (Woodford 2024) only emphasize that this “exquisite bird fossil provides clues to the evolution of avian brains”, and quotes one of the authors as saying that “Navaornis fills a roughly 70-million-year-long gap in our understanding of how the distinctive brains of modern birds evolved.” Reuters reports that this “’One-of-a-kind’ skull fossil from Brazil reveals bird brain evolution” (Dunham 2024). Is it really just a happy accident that there is no mention of the unexpected similarity of this alleged primitive bird to modern birds and the implied problems for bird evolution? Why do we mostly hear only one side of the story in the media? I suppose we must be protected from dangerous questions that could come up.

References

Chiappe LM, Navlón G, Martinelli AG, de Souza Carvalho I, Miloni Santucci R, Wu Y-H & Field DJ 2024. Cretaceous bird from Brazil informs the evolution of the avian skull and brain. Nature 635(8038), 376–381. DOI: https://doi.org/10.1038/s41586-024-08114-4
Dunham W 2024. ‘One-of-a-kind’ skull fossil from Brazil reveals bird brain evolution. Reuters November 13, 2024. https://www.reuters.com/science/one-of-a-kind-skull-fossil-brazil-reveals-bird-brain-evolution-2024-11-13/
News Staff 2024. 80-Million-Year-Old Enantiornithine Fossil Fills Gap between Archaeopteryx and Modern Birds. SciNews November 14, 2024. https://www.sci.news/paleontology/navaornis-hestiae-13425.html
Woodford J 2024. Exquisite bird fossil provides clues to the evolution of avian brains. New Scientist November 13, 2024. https://www.newscientist.com/article/2456043-exquisite-bird-fossil-provides-clues-to-the-evolution-of-avian-brains/


Wednesday, 20 November 2024

On mathematics antiDarwinian bias.

 Protein Designers Explore Sequence Space


The twenty major amino acids used in life as we know it can be assembled in countless ways. What portion of that vast sequence space is functional? This question has had a long history among Darwin skeptics because the answer contributes to probability calculations for assessing the explanatory power of chance vs design for the origin of life.

Historical Background

The Wistar Institute symposium in 1966 has often been cited by ID advocates as a death knell for hopes that functional proteins would spontaneously arise by chance. Around this time in the late 1960s, about a decade after Francis Crick had proposed his famous “sequence hypothesis” for DNA and proteins, my father James F. Coppedge recognized the informational character of biomolecules. Working on a graduate degree in chemistry at UCLA, he attempted to estimate the “usable” portion of sequence space by analogy with useful combinations of letters in English words and sentences. He tested the analogy by searching through tens of thousands of random letters. In his 1973 book,1 he applied his rough estimate of useful text strings arising by random selections to argue for the extreme improbability of arriving at a single usable protein by chance, even granting a world-sized primordial soup of plentiful amino acids combining under ideal conditions at fantastically rapid rates. 

In 1984, Thaxton, Bradley and Olsen in their book The Mystery of Life’s Origin (updated in 2020), wrote about the formidable challenge of overcoming “configurational entropy” in sequence space. Douglas Axe, in his book Undeniable (2016), wrote about biochemistry experiments he performed to determine the limits of functionality by seeing how far a well-studied protein could be altered and still perform. His calculations, along with my father’s memorable “amoeba analogy” from his book (ch. 7) led to an episode in the Illustra Media film Origin (excerpted in their shorter video First Life).

William Dembski and Stephen Meyer have also discussed at length the informational nature of protein sequences and the probabilistic resources for accounting for them by chance in their books.2 Studies like these have all agreed that functional proteins occupy an infinitesimal fraction of sequence space, like a vanishingly small box in the corner of a sheet of graph paper.

The New Explorers

The arrival of AI tools such as AlphaFold that can predict protein folds for computer-generated polypeptides has opened up new ways to explore functional portions of sequence space outside of biology.3 In a fascinating News Feature in Nature on October 15, Ewen Callaway told about international contests to find new proteins. Promises of lucrative prizes are motivating explorers from around the world to join “protein-design competitions [that] aim to sift out the functional from the fantastical.” Notice the key word design:

Contests have driven key scientific advances in the past, particularly for the field of protein-structure prediction. This latest crop of competitions is drawing people from around the world into the related field of protein design by lowering the barrier to entry. It could also quicken the pace of validation and standards development and perhaps help to foster community. “It will push the field forward and test methods more quickly,” says Noelia Ferruz Capapey, a computational biologist at the Centre for Genomic Regulation in Barcelona, Spain.

The tournaments bypass the stodgy method of grant application, peer review and publication, speeding discovery and stimulating involvement. Callaway describes half a dozen competitions generating tens of thousands of candidate sequences, even from “people with no professional experience in biology” using their gaming computers at home.

Englert says that the high-quality entries from people who aren’t established researchers reminds him of the garage-tinkering origins of Apple, Microsoft and other tech giants. “It would have taken them two years of studying and joining a lab to get to the point where they can get started. Here they can do it over a weekend.” He imagines a future in which freelance protein designers vie for bounties set by companies, academic labs and others seeking a custom molecule.

Is This Evolution?

These contests are goal-directed with specific criteria, such as “looking for proteins capable of attaching to a growth hormone receptor called EGFR that is overactive in many cancers.” Another contest “tasked entrants with re-engineering an existing protein — a plant-virus enzyme used widely in protein purification — to make the molecule more efficient.”

Efforts at this kind of “directed evolution” have been around for a long time in labs. As Dembski explains in No Free Lunch and The Design Inference 2nd Ed, these “evolutionary algorithms” are not random searches comparable to natural selection, which must survive at each mutation, but intelligently guided, goal-directed projects. In the contests described by Callaway, success for the contestants is judged by a sequence’s match to a foreordained goal: it must fold, and it must bind to a specified molecule. A contestant may attempt random searches in sequence space but has the intelligence to determine whether a sequence meets the criteria.4 Even if the contestant does not know in advance what approach will be successful, he or she can perform an intelligently guided “search for a search” as if looking through a pile of treasure maps to identify which is best for locating a treasure.

It is misleading, therefore, to call a contest “Evolved 2024” or to name a new AI biology startup “EvolutionaryScale.” These have nothing to do with Darwinian evolution. This type of equivocation confuses the public. It resembles Darwin’s own blunder in comparing natural selection to artificial selection, a fallacy he continued all his life.5 

Intelligence Far Surpasses the Reach of Chance

The capabilities of intelligence over chance are profound. My father calculated that on average it would take chance 1,500 years (“If a person could draw and record one coin every five seconds day and night”) to arrange coins numbered one to ten in order—something an eight-year-old child could do in a few moments (p. 51). From there, he calculated how long it would take to expect success by chance at arranging the phrase “The Theory of Evolution” from a set containing lower- and uppercase letters and a space. The probability was 1 in 4.5 x 1039. Envisioning a machine attempting this project that could perform a billion draws per second at the speed of light, he concluded that the time required to expect one success would be 28 trillion times the assumed age of the earth. Then he compared it to the capabilities of a child:

So chance requires twenty-eight trillion times the age of the earth to write merely the phrase: “The Theory of Evolution,” drawing from a set of small letters and capitals as described, drawing at the speed of light, a billion draws per second! Only once in that time could the letters be expected in proper order.

Again, a child can do this, using sight and intelligence, in a few minutes at most. Mind makes the difference in the two methods. Chance really “doesn’t have a chance” when compared with the intelligent purpose of even a child. 

If chance had to rely on earthquakes and wind to do the job, it would never happen.6 

While we can hope for revolutionary insights from the contests to find new proteins, they will come about by intelligent design, not by evolution.

Notes

Coppedge, Dr James F, Evolution: Possible or Impossible? (Zondervan, 1973). This book was one of the few pre-ID Movement publications to use the phrase “intelligent design.” After eight printings, his popular and influential book went out of print but he self-published it through 2002. I have the remaining stock of copies for those interested. A digitized version is available at this link: http://crev.epoi 
Dembski, The Design Revolution (2004), ch 9-10; The Design Inference (2nd ed., 2023). Meyer, Signature in the Cell (2009), ch 8-10.
To make exploration of sequence space somewhat tractable, one must assume using only the canonical amino acids and assume they were already left-handed and join solely with peptide bonds at the proper linkages. Chance, of course, wouldn’t care about those details. 
Success depends on context. One of the longest meaningful alphabet sequences my father detected was “AGMCAP”—an imaginative stretch, but potentially useful in some contexts (p. 104). Protein sequences are even more demanding since they must fold and perform a useful function in three dimensions within a cell.
Robert Shedinger, Darwin’s Bluff (2024), p.71-78, 171-172, 199-200.
This is not an exaggerated claim. Dr. A. E. Wilder-Smith debunked the old Huxley analogy of a million monkeys typing Shakespeare given enough time with the observation that biochemical reactions are reversible. The monkey-typewriter analogy depends on assuming that the letters stay on the page. If they fall off soon after they are typed, a Shakespeare sonnet will never emerge. In biochemistry, peptide bonds fall apart in water. A growing random chain, therefore, would not survive for long in the best of real-world conditions, nor would any progress in the meaningful alphabet string survive the next quake or gust of wind.


Saturday, 9 November 2024

Yet more secular mysticism?

 Fossil Friday: An Ediacaran Animal with a Question Mark


This Fossil Friday discusses Quaestio simpsonorum from the Late Precambrian of the Ediacaran biota in Australia, which is, well, actually I have no idea what it really is, and neither does anyone else, which makes its genus name very fitting indeed. Here is the backstory of these fossils that were discovered in the 555-million-year-old sandstones of Nilpena Ediacara National Park in the South Australian outback, and were reconstructed as inflated disc-shaped organisms that were floating over microbial mats on the ancient seafloor like a Roomba.

Just a few days ago the study by Evans et al. (2024) with the description of this fossil organism hit the news with sensationalist headlines like “Ancient ‘sea Roomba’ tells a 555-million-year-old story of our evolution” (Thompson 2024), or “Flinders fossil unlocks secrets of first animals on Earth” (Government of South Australia 2024), or “Florida State University scientist discovers one of the earth’s earliest animals in Australian outback” (Harris 2024), or “Enigmatic Fossil Shows Signs Of Being Earth’s First Animal” (Bressan 2024). It was boldly celebrated as “oldest evidence for complex, macroscopic animals” (de Lazaro 2024) and “the earliest moving animals” (Luntz 2024). Wow, that surely sounds like something important

Is It Really Based on Solid Evidence? 

A first look at the images of the fossil is not very encouraging: The fossils look like structureless blobs, and many fossil collectors might not even have bothered to pick them up. Certainly the actual study showed much more significant details? No, not at all which is a real bummer. Even co-author García-Bellido explicitly admitted to IFLScience “that all we really know about Quaestio is the shape of its outsides” (Luntz 2024). Yes, you heard that right. All we know about this fossil is the shape, which is nothing more than a few-inch-large round impression with a question-mark-like fold in the middle that originates from a kind of notch. Are any organs visible that suggest that it was a multicellular animal? No. Any bilateral symmetry? No, but this does not prevent the scientists from speculating that in spite of the external asymmetry, it might have been a pioneer bilaterian ancestor, because humans are bilaterian animals and internally asymmetrical (authors quoted in de Lazaro 2024). You can’t make this stuff up: They seriously compare a Precambrian blob of jello with a highly derived modern human and claim that external asymmetry in the former and internal asymmetry in the latter could somehow correspond, even though the internal asymmetry of humans does not belong to the ground plan of vertebrate animals even according to mainstream evolutionary biology. This is ridiculous junk science, based on almost useless fossil evidence. Actually, there are even inorganic pseudofossils like salt pseudomorphs that look quite similar to this stuff. All the elaborate hypotheses in the new study are based on the simple circumstance that the structures in the stone seem to show some polarity. Here is news: almost every organism does show some polarity including most protists and plants. This is much ado about nothing.

What about the alleged evidence for motility? Are there any trace fossils that really document active motility? No, but again the scientists claim otherwise. Why? Because a few of the fossils have a similar shaped and similar sized impression close to them, which they interpret as evidence for active movement. However, such structures had been already described under the name Epibaion for the Ediacaran dickinsoniids and are highly controversial in their interpretation as I discussed in a previous article (Bechly 2018). I highly recommend to read the paragraph on these alleged trace fossils in this latter article of mine. While some experts indeed interpreted those structures as grazing traces, others considered the serial impressions as made by dead organisms displaced by slow currents before finally being buried. I personally observed the latter phenomenon in fossil dragonflies from the Upper Jurassic Solnhofen limestone (see Tischlinger 2001). The alleged traces show no continuity and thus no evidence for motility. But who am I, or world leading experts like A. Yu Ivantsov (also see Brasier & Antcliffe 2008 and McIlroy et al. 2009), to disagree with some evolutionary biology graduate student’s views, who thinks that this is “a clear sign that the organism was motile” (Bressan 2024, Harris 2024)? What makes things worse is the whole house of cards of far-reaching hypotheses that are built on this dubious foundation. The authors for example speculate that “the presence of muscles and/or a nervous system based on inferred behaviors would, if verified, constitute further evidence of more advanced differentiation” (Evans et al. 2024). Problem is: they are not verified. There is not a shred of evidence for muscles or nervous systems in any of the fossils! There is not even valid evidence for the inferred behaviors from which the presence of muscles and nervous system was inferred. It is quite revealing for the poor state of evolutionary biology that such imaginative story-telling is not only allowed but apparently welcome in a peer-reviewed science journal titled Evolution & Development.

An “Animal” with a Question Mark

In short: There is neither any convincing evidence for a metazoan affinity of Quaestio, nor for its motility. It is truly an Ediacaran “animal” with a question mark! The much more obvious conclusion is that Quaestio is just another problematic organism of the Ediacaran biota that cannot be connected to any living group. Actually, the scientists themselves did not suggest a direct relationship with any living animals but rather compared Queastio with dickinsoniids, which are of highly questionable animal relationship themselves (Bechly 2018). Sure, Quaestio and dickinsoniids still could be placozoan or coelenterate grade animals, or xenacoelomorph flatworms, even though none of them agrees in size, shape, symmetry or anatomy, or any relevant diagnostic similarities. Thus, they could as well be giant protists (Vendobionta sensu Seilacher), or rather an independent extinct group of multicellular organisms, or almost anything else such as fungi or lichens. There are also similarities between Quaestio and the trilobozoan Ediacaran fossils like Tribrachidium that were initially misidentified as echinoderms, or to other circular Ediacaran fossils like Cyclomedusa (featured above) that were initially misidentified as jellyfish, but later reinterpreted as holdfasts or microbial colonies. We have no clue what all these Ediacaran biota organisms really were. To claim that such undefinable blobs in sandstone represent fossils of the oldest motile animals is massively overselling the evidence to say the least.

References

Bechly G 2018. Why Dickinsonia Was Most Probably Not an Ediacaran Animal. Evolution News September 27, 2018. https://evolutionnews.org/2018/09/why-dickinsonia-was-most-probably-not-an-ediacaran-animal/
Brasier M & Antcliffe J 2008. Dickinsonia from Ediacara: a new look at morphology and body construction. Palaeogeography, Palaeoclimatology, Palaeoecology 270, 311–323 DOI: https://doi.org/10.1016/j.palaeo.2008.07.018
Bressan D 2024. Enigmatic Fossil Shows Signs Of Being Earth’s First Animal. Forbes October 19, 2024. https://www.forbes.com/sites/davidbressan/2024/10/18/enigmatic-fossil-shows-first-signs-of-being-earths-first-animal/
de Lazaro E 2024. New Species of Complex Ediacaran Animal Discovered in Australia. SciNews October 17, 2024. https://www.sci.news/paleontology/quaestio-simpsonorum-13355.html
Evans SD, Hughes IV, Hughes EB, Dzaugis PW, Dzaugis MP, Gehling JG, García-Bellido DC & Droser ML 2024. A new motile animal with implications for the evolution of axial polarity from the Ediacaran of South Australia. Evolution & Development e12491, 1–11. DOI: https://doi.org/10.1111/ede.12491
Government of South Australia 2024. Flinders fossil unlocks secrets of first animals on Earth. Environment SA News October 14, 2024. https://www.environment.sa.gov.au/news-hub/news/articles/2024/10/flinders-fossil-unlocks-secrets-of-first-animals-on-earth
Harris M 2024. Florida State University scientist discovers one of the earth’s earliest animals in Australian outback. Florida State University October 14, 2024. https://news.fsu.edu/news/university-news/2024/10/14/florida-state-university-scientist-discovers-one-of-the-earths-earliest-animals-in-australian-outback/
Luntz S 2024. One Of The Earliest Moving Animals Had A Very Quizzical Shape. IFLScience October 22, 2024. https://www.iflscience.com/one-of-the-earliest-moving-animals-had-a-very-quizzical-shape-76460
McIlroy D, Brasier MD & Lang AS 2009. Smothering of microbial mats by macrobiota: implications for the Ediacara biota. Journal of the Geological Society 166, 1117–1121. DOI: https://doi.org/10.1144/0016-76492009-073
Thompson B 2024. Ancient ‘sea Roomba’ tells a 555-million-year-old story of our evolution. New Atlas October 14, 2024. https://newatlas.com/biology/fossil-quaestio-evolution/
Tischlinger H 2001. Bemerkungen zur Insekten-Taphonomie der Solnhofener Plattenkalke. Archaeopteryx 19, 29–44.

Saturday, 2 November 2024

More iconoclasm from the fossil record.

Fossil Friday: New Fossil Evidence Challenges Another Icon of Evolution


This Fossil Friday features the skull of Cynognathus crateronotus, a mammal-like reptile from the Middle Triassic of the southern hemisphere landmasses that had formed the ancient supercontinent Gondwana. It belongs to a group called cynodontians. The recent analysis of the jaw anatomy of fossil cynodonts from South America challenged some longstanding evolutionary ideas.

When evolutionists are asked what in their view represents the best evidence for the Darwinian story of common descent with modification, they will generally refer to the fossil record and especially to supposed transitional series like those of horses, elephants, whales, hominins, fishapods to tetrapods, dinos to birds, and most of all the transition from reptiles to mammals. The latter allegedly shows an unambiguous transformation of the jaw articulation from a primitive reptilian state to the derived mammalian condition, correlated with a reduction of bones and an incorporation of the original jaw articulation into the mammalian ear as auditory ossicles (Reichert-Gaupp theory).

A More Complicated Picture

However, a closer look at the actual fossil evidence shows a much more complicated picture that involves multiple independent origins of anatomical similarities. In a seminal study on the evolution of the mammalian middle ear, the authors admitted that “current hypotheses on the convergent evolution of middle ear bones are complex and controversial, partly because of a lack of phylogenetic resolution and partly because the interpretation of the fossil evidence is difficult” (Ramírez-Chaves et al. 2016). They concluded that “the departure of postdentary bones from the dentary to form a partial mammalian middle ear (PMME); … occurred convergently in the northern hemisphere ancestors of therians and the southern hemisphere ancestors of monotremes … the transition from a PMME to a definite mammalian middle ear (DMME) ocurred [sic] multiple times, including at least three cases of independent evolution within extant mammals (in monotremes, metatherians and eutherians).”

Now, a new study complicated this scenario even more: The scientists studied the well-preserved fossil remains of three key species of probainognathian cynodonts, viz. Brasilodon quadrangularis and Riograndia guaibensis from the Late Triassic of Brazil, as well as Oligokyphus major from the Early Jurassic of Great Britain. They used CT scanning to digitally reconstruct the jaw joint of these animals and found something very unexpected and surprising (Luo 2024). The jaw joint anatomy of the two Brazilian species was very different, with the joint of Riograndia being more mammal-like than that of Brasilodon, even though the later genus is considered as closer related to modern mammals. Furthermore, Riograndia was dated to be about 17 million years older than any other previously known mammal-like reptile with such an advanced jaw articulation. The authors concluded that “the dentary-squamosal contact, which is traditionally considered to be a typical mammalian feature, therefore evolved more than once and is more evolutionary labile than previously considered.”

Interesting News for a Departed Colleague

The press release unashamedly speaks about “rewriting our understanding of mammal evolution” (News Staff 2024), and elaborates that:

This indicates that the defining mammalian jaw feature evolved multiple times in different groups of cynodonts, earlier than expected. The findings suggest that mammalian ancestors experimented with different jaw functions, leading to the evolution of mammalian traits independently in various lineages. The early evolution of mammals, it turns out, was far more complex and varied than previously understood.

The lead author of the new study, Dr. James Rawson from the University of Bristol, said (quoted in News Staff 2024):

This indicates that the defining mammalian jaw feature evolved multiple times in different groups of cynodonts, earlier than expected. The findings suggest that mammalian ancestors experimented with different jaw functions, leading to the evolution of mammalian traits independently in various lineages. The early evolution of mammals, it turns out, was far more complex and varied than previously understood.

The lead author of the new study, Dr. James Rawson from the University of Bristol, said (quoted in News Staff 2024):

What these new Brazilian fossils have shown is that different cynodont groups were experimenting with various jaw joint types, and that some features once considered uniquely mammalian evolved numerous times in other lineages as well.

Dr. Zhe-Xi Luo, one of the world’s leading experts on mammalian origins and not involved in the new study, commented that this is “a jaw-dropping discovery about early mammals” (Luo 2024). It certainly is, and it definitely looks like we are witnessing the beginning of the dismantling of yet another icon of evolution, which would have been very interesting news to my recently deceased friend and colleague Jonathan Wells, who had described many such cases in his ground-breaking books.

References

News Staff 2024. New Cynodont Fossil Discoveries are Rewriting Our Understanding of Mammal Evolution. SciNews September 25, 2024. https://www.sci.news/paleontology/brazil-cynodonts-13286.html
Luo Z-X 2024. A jaw-dropping discovery about early mammals. Nature 634, 305–306. DOI: https://doi.org/10.1038/d41586-024-03038-5
Ramírez-Chaves HE, Weisbecker V, Wroe S et al. 2016. Resolving the evolution of the mammalian middle ear using Bayesian inference. Frontiers in Zoology 13: 39, 1–10. DOI: https://doi.org/10.1186/s12983-016-0171-z
Rawson JRG, Martinelli AG, Gill PG, Soares MB, Schultz CL & Rayfield EJ 2024. Brazilian fossils reveal homoplasy in the oldest mammalian jaw joint. Nature 634, 381–388. DOI: https://doi.org/10.1038/s41586-024-07971-3

Saturday, 26 October 2024

Yet further echoes of the Cambrian explosion.

 Fossil Friday: An Extinct Animal Body Plan from the Cambrian Explosion


This Fossil Friday features Herpetogaster collinsi from the Middle Cambrian Burgess Shale in Canada. It is as an example of an extinct group of animals called Cambroernida, that originated in the Early Cambrian and disappeared in the Late Devonian.

Eldonia — The Medusa That Wasn’t

The Cambrian fauna of the famous Burgess Shale includes numerous enigmatic fossils that for a long time eluded any attempts by evolutionary scientists to place them in the tree of life. One of these fossils is Eldonia ludwigi, which was a soft-bodied animal with disc-shaped body, a coiled gut, and a ring of feeding tentacles around the oral opening. More than hundred years ago, Charles Walcott (1911) collected 550 specimens from the Burgess Shale and many more have meanwhile been found, including specimens from the Early Cambrian of Chengjiang in southwest China (Sun & Hou 1987, Chen et al. 1995, Zhu et al. 2002), the Middle Cambrian of Utah (Conway Morris & Robinson 1988) and Siberia (Friend 1995, Ivantsov 1998, Friend et al. 2002), and the Late Ordovician Erfoud sandstones of Morocco (Alessandrello & Bracchi 2003). Furthermore, seven other genera of eldoniids were described from different localities and strata. The latest fossil record is the putative eldoniid Paropsonema from the Upper Devonian of New York (Hagadorn & Allmon 2019), which was first described by Clarke (1900) as an echinoderm, which is an attribution that was still supported by Conway Morris (1993). However, the systematic affinities and lifestyle of eldoniids remained enigmatic. Because of the medusoid appearance some experts suggested an identification as cnidarian siphonophore or jellyfish (Madsen 1956, 1957, 1962, Lemche 1960, Seilacher 1961, Sun & Hou 1987), but the most favored alternative interpretations included an attribution to lophophorates (Dzik 1991, Chen et al. 1995, Dzik et al. 1997, Zhu et al. 2002) or to holothurian echinoderms (sea cucumbers) (Walcott 1911, Clark 1913, Durham 1974). Zhu et al. (2002) said that “the new anatomical information emphasize close phylogenetic relations with lophophorates (U-shaped intestine, circumoral tentacles and ectodermal, marginal accreted disc), though some features (e.g. dendritic tentacles, ventral pustules that may relate to reduced podia) do not exclude affinities with echinoderms.” Because of this strange and ambiguous combination of characters, Conway Morris & Robinson (1988) had concluded that “the higher taxonomic affinities of this genus are best regarded as uncertain”, but only a few years later Conway Morris (1993) considered eldoniids as pre-echinoderm deuterostomes (also see Friend 1995, Caron et al. 2010, and MacGabhann 2012), which happens to represent the currently preferred view (see below). Even the lifestyle of eldoniids was reconstructed very differently (see discussion in Caron et al. 2010): some scientists considered them as pelagic filter feeders (e.g., Clark 1913, Durham 1974, Chen et al. 1995, Zhu et al. 2002), while others re-interpreted them as sedentary benthic deposit feeders (Luo et al. 1999). Looks like there is not much we really know for sure about ancient life on Earth.

Herpetogaster — An “Alien” Life Form from Deep Time

Herpetogaster is another very strange fossil organism known from more than hundred specimens from the Middle Cambrian of British Columbia and Nevada as well as the Early Cambrian Chengjiang biota of China (Caron et al. 2010, Kimmig et al. 2019, Yang et al. 2020, 2023). It had a long and narrow stalk, a curved and segmented sac-like body, and pair of branched feeding tentacles around the apical mouth. Herpetogaster was about 3-4 cm long and was often found attached to fossil sponges. The quite similar genus Phlogites (= Cheungkongella) was originally described as urochordate (tunicate) by Shu et al. (2001), but re-interpreted as a tentaculate similar to entoprocts (Kamptozoa) by Chen et al. (2003) and Hou et al. (2006), and finally identified as a stem ambulacrarian by Caron et al. (2010) and Li et al. (2023). Shu et al. (2010) disagreed and still considered a tunicate affinity. These determinations seemingly jump between major groups of animals like in a wild guessing game.

Cambroernida — A Novel Animal Body Plan from the Paleozoic

Caron et al. (2010), who first described Herpetogaster collinsi from the Burgess Shale biota, already recognized that this organism likely represents a deuterostome animal, which they tentatively attributed to the stem group of hemichordates and echinoderms that are united in a clade called Ambulacraria. They also recognized that the enigmatic eldoniids, in spite of their discoidal shape, seem to be closely related to Herpetogaster and share a similar body plan. These animals are so distinct and so different from all other known animal phyla, that Caron et al. erected a new clade named Cambroernida to accommodate them. They did not formerly rank it as a new phylum, but it is very clear that this clade would deserve such a high rank in the taxonomic hierarchy as one of the numerous distinct body plans of bilaterian animals that originated in the Cambrian Explosion (see Bechly 2024).

To understand how weakly supported the phylogenetic and evolutionary hypotheses really are, it is worthwhile to quote from the discussion in Caron et al. (2010):

Arriving at a precise phylogenetic position for the cambroernids, therefore, has proved difficult. On balance a place amongst the tentaculate lophotrochozoans seems to be less persuasive. Given a place within the ecdysozoans is even less plausible, then the final possibility must be to look to the deuterostomes. Here, as noted the options revolve around a series of possibilities, including a stem- group echinoderm, a hemichordate or an ambulacrarian. Whilst this list of possibilities might seem to leave the matter largely unconstrained, it is important to stress that from a Cambrian perspective the morphological differences between these various alternatives were probably insignificant. If, for the sake of the argument, the position of the cambroernids does indeed lie near the branching point of the two main ambulacrarian clades that led ultimately to the echinoderms and hemichordates, then we should not be surprised that it seems reminiscent of both pterobranchs and pre-radial echinoderms. … Finally, if accepted as some sort of deuterostome then these fossils have some further interesting implications. … Whilst many of the evolutionary steps involved in this process are still hypothetical, we suggest that animals similar to Herpetogaster may, in terms of the fossil record, be our best current glimpse of a very primitive ambulacrarian.

This is a lot of uncertainty as shaky foundation for a house of cards of evolutionary speculations. It is likely the reason why, despite Caron et al.’s work, some other experts still think that “the taxonomic affinities of these groups remain uncertain” (Hagadorn & Allmon 2019), even though some others had readily excepted the cambroernid-hypothesis (MacGabhann 2012). The most recent work by Li et al. (2023) is a perfect example for the dubious evolutionary hypotheses built on such shaky assumptions. The latter author concluded that:

As Herpetogaster has been recovered at the base of the Ambulacrarian tree in recent phylogenies, a planktonic larval stage is suggested, which implies, that the last common ancestor of the Ambulacraria might have already had planktonic larvae or that such larvae developed multiple times within the Ambulacraria

Note the typical Darwinian gobbledygook with key words like “suggested” and “might,” combined with the anything goes approach of either the character is homologous or it developed multiple times. The real information content of such statements is basically zero.

Anyway, the cambroernid-hypothesis by Caron et al. has more recently been corroborated by Li et al. (2023), who analyzed the discoidal metazoan Rotadiscus grandis from the Early Cambrian Chengjiang biota, a putative eldoniid. According to these scientists, the results of their research implied that “key traits of extant forms, such as a post-anal region, gill bars, and a U-shaped gut, evolved through convergence.” Wait a moment and read this carefully again. It means nothing less than the following: characteristic similarities of one of the two major branches of metazoan animals (i.e., Protostomia and Deuterostomia) are not based on common descent but independently acquired. Furthermore, the scientists found “Rotadiscus exhibits a chimeric combination of ambulacrarian and chordate characters.” However, these chordate-like features (e.g., a serialized body) are not known from living hemichordates and echinoderms, implying secondary loss or another convergence. The more we know about the distribution of certain anatomical features in fossil organisms, the more the initially apparent congruent distribution of similarities among recent organisms evaporates as a mirage, an artifact of incomplete knowledge. In reality, many traits exhibit a highly incongruent pattern of similarities that do not easily align with a nested hierarchy that could be translated into a tree of life. One of the strongest arguments in favor of Darwinian evolution gets more and more dismantled, which totally vindicates the critique by Michael Denton that evolution is a theory in crisis, in spite of the desperate attempts of denialism by mainstream academia.

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