The fuse of the cambrian explosion?

 Fossil Friday: Update on the Dubious Nature of the Precambrian Gabonionta

Gunter Bechly

In a Fossil Friday article last year (Bechly 2023) I discussed the dubious status of an assemblage of alleged Precambrian macrofossils from West Africa that have been informally called Gabonionta. Meanwhile, two new articles on the subject have been published, so that I here present an updated and expanded version of my article.

“According to conventional thinking, unequivocal evidence for eukaryotic fossils first appeared in the geological record some 1700–1600 million years ago” (Chi Fru et al. 2024). However, in 2008 the Moroccan-French geologist Prof. Abderrazak El Albani from the University Poitiers discovered strange three-dimensionally preserved radial structures in Proterozoic rocks of the Francevillian Formation in the West African country Gabon, which are believed to be about 2.1 billion years old. The ear-shaped structures of up to 6.7 inch size were interpreted as earliest fossil evidence for oxygen-respiring, multicellular eukaryotic life forms and were published two years later in the prestigious journal Nature (El Albani et al. 2010, Maxmen 2010).

Somewhat More Cautious

This original description was somewhat more cautious than the later public presentation of the discovery. The authors said:

We consider it most likely that these structures represent fossilized colonial organisms … it is also possible that they represent colonial eukaryotes. … Although we cannot determine the precise nature and affinities of the 2.1-Gyr macroorganisms from the Francevillian B Formation of Gabon, we interpret these fossils as ancient representatives of multicellular life, which expanded so rapidly 1.5 Gyr later.

In 2014, these findings were first presented to the general public with a special exhibition titled “Experiment Life: The Gabonionta” opened in March 2014 at the Natural History Museum in Vienna (), which also featured a 40-minute documentary film by the University of Poitiers about the discovery. This exhibition was accompanied by a sensationalist media campaign, which included fancy headlines such as: “Gabonionta: sensational discovery in Vienna” (ORF 2014), “Gabonionta, the little revolutionaries of evolution” (Vosatka 2014), or “Gabonionta: How multicellular organism tried to conquer the Earth” (Anonymous 2014).

Remarkable and Highly Unusual

It is remarkable and highly unusual in bioscience that the new taxon Gabonionta was never formally described as scientific name, but only used informally in public presentations and press releases. While El Albani refrained from formally naming the fossils, the new name Gabonionta was first introduced by the head of the paleontology department, Dr. Matthias Harzhauser, on occasion of the mentioned special exhibition at the Natural History Museum of Vienna. Therefore, it is commonly thought that this name Gabonionta, which designates a supposed independent and extinct branch of multicellular life, is not taxonomically valid because it was not properly described according to the international rules of nomenclature. However, this is not true, because these rules do not apply to higher taxa above the family group level. Even if this name was only used in popular science publications, it is as scientifically valid and available just as other higher taxonomic names such as Eukaryota or Metazoa.

Anyway, there are more important issues with this discovery: other experts such as the late great German paleontologist Prof. Adolf Seilacher remained highly sceptical about the interpretation and suggested that the structures rather represent only pseudo-fossils formed by abiotic pyrite crystals during the diagenesis of the rocks. El Albani et al. (2014) responded to this critique and objected that not all of the fossils are pyritized and that the fossils formed at the same time as the sediment and therefore could not have been produced later by metamorphic processes. However, the initial critique was later strongly corroborated by the discovery of very similar structures from 1.1 billion year old sediments of Lake Michigan that were described by the authors as inorganic concretions (Anderson et al. 2016). Therefore, Javaux & Lepot (2018) remarked that “the identity of these macrostructures remains unknown and their biogenicity is questionable”.

Just a year later, El Albani et al. (2019) defended the organic origin and syngenicity of some other alleged fossils from the Francevillian Formation, and boldly suggested that they were analog to “the aggregation of amoeboid cells into a migratory slug phase in cellular slime molds.” This cannot be so easily dismissed, as this publication includes among its co-authors some world renowned experts such as Drs. Stefan Bengtson, Luis Buatois, and Gabriela Mangano. Nevertheless, other experts remained very much unconvinced. More recently, Fakhraee et al. (2023) again came to the devastating finding that these structures could rather represent abiotic concretions and synaeresis cracks. They concluded that “in light of their stratigraphic age, unusual morphology, and the relative rarity of these features, a eukaryote affinity for these features—or affinity with analogously complex multicellular organisms — remains uncertain.” It looks like the dubious name Gabonionta may not even refer to any organism that ever existed. The scientists simply made up a new domain of life, based on nothing but inorganic patterns in ancient rocks.

Nothing But Hype?

Is there any other evidence that this sensational discovery was nothing but hype? Sure there is: after the 2014 media circus nobody ever published any primary research again about these “fossils” and the mysterious Gabonionta, at least until last year (see below). Even in their newer papers about the Francevillian Biota, El Albani and his colleagues only described lenticular structures produced by agglutinated protists (Lekele Baghekema et al. 2017, Reynaud et al. 2017, El Albani et al. 2019, 2023), but no longer promoted the presence of truly multicellular organisms. The silence was deafening!

Even, the mentioned two most recent works on the assumed Francevillian fossils, which appeared after my first article on this subject, again only defended their biogenic origin and eukaryotic nature. Ossa Ossa et al. (2023) did not base their conclusions on a study of the fossil structures but on geochemical evidence from Zinc enrichment, which could be consistent with eukaryotic metabolism. However, they openly admitted that “geochemical evidence presented here also cannot resolve the exact type of eukaryotic organisms that inhabited the Francevillian basin, i.e., colonies of multiple cells or individual, large complex multicellular organisms.” Moreover, there is no independent confirmation yet that the enrichment of Zinc isotopes could not be alternatively better explained with inorganic processes or prokaryotic microbial activity. After all, these structures are pyritized, which is quite typical for bacterial metabolic activity during fossilization (Janssen et al. 2022). Ossa Ossa et al. devote a whole lengthy chapter of their discussion to the question if the Zinc enrichment is based on prokaryotic or eukaryotic metabolic processes, but in the last paragraph they have to admit that:

However, it is important to emphasize here that studies of Zn isotope fractionation by eukaryotes have been focused exclusively on modern photosynthetic eukaryotes. This leaves the uncertainty whether strong enrichment in light Zn isotopes represents a distinct trait of the whole eukaryotic domain and whether the Francevillian Group fossilized structures represent photosynthetic or non-photosynthetic eukaryotes.

Indeed, Ossa Ossa et al. are careful to conclude that their data only “may [my emphasis] point to their eukaryotic rather than prokaryotic affinity” and “once confirmed [my emphasis], this would provide a critical calibration point for eukaryogenesis.”

The Usual Evolutionist Word Salad

The newest study by Chi Fru et al. (2024), which has Dr. El Albani as senior author, did not look at the alleged fossils either, but instead found a correlation of the Francevillian Formation with a “previously unrecognized local pulse in dissolved seawater P concentration, of comparable magnitude to Ediacaran seawater levels”, which seems to have been caused by “an episode of intense submarine hydrothermal alteration of a nutrient-rich seafloor reservoir”. The authors interpret this slim data point as evidence that “hydrothermal seawater eutrophication triggered local macrobiological experimentation in the 2100 Ma Paleoproterozoic Francevillian sub-basin” and “nutrient enrichment initiated localized emergence of large colonial macrofossils in the Franceville sub-basin.” In spite of these weak speculations based on highly circumstantial evidence, the new study was sold to the public in a press release titled “complex life on Earth began around 1.5 billion years earlier than previously thought” (Cardiff University 2024). If you read the original study you will find the usual evolutionist word salad of “may have”, “could have”, “likely have”, “possibly reflects”, and “might explain”. Not exactly the usual vocabulary of hard science.

Here is what I tentatively suggest is more likely what really happened: a surplus of nutrients (such as phosphates) triggered a lot of microbial activity that resulted in different concentrations of elements and the formation of pseudo-fossils. Maybe some of the protists already were eukaryotic and maybe some of them formed colonial aggregations, or maybe not, we have no clue. What we definitely do not find here is any credible evidence for an evolutionary transition to genuine multicellular eukaryotes, as was initially claimed with the overhyped discovery of the Gabonionta.

References

Anderson RP, Tarhan LG, Cummings KE, Planavsky NJ, Bjørnerud M 2016. Macroscopic structures in the 1.1 Ga continental Copper Harbor Formation: Concretions of fossils? Palaios 31(7), 327–338. DOI: https://doi.org/10.2110/palo.2016.013

Anonymous 2014. Gabonionta: Wie Mehrzeller versuchten, die Erde zu erobern. OÖNachrichten March 8, 2014. https://www.nachrichten.at/panorama/weltspiegel/Gabonionta-Wie-Mehrzeller-versuchten-die-Erde-zu-erobern;art17,1323424

Bechly G 2023. Fossil Friday: How an Austrian Scientist Concocted a New Domain of Life called Gabonionta. Evolution News June 2, 2023. https://evolutionnews.org/2023/06/fossil-friday-how-an-austrian-scientist-concocted-a-new-domain-of-life-called-gabonionta/

Cardiff University 2024. Complex life on Earth began around 1.5 billion years earlier than previously thought, new study claims. Phys.org July 29, 2024. https://phys.org/news/2024-07-complex-life-earth-began-billion.html

Chi Fru E, Aubineau J, Bankole O, Ghnahalla M, Soh Tamehe L & El Albani A 2024. Hydrothermal seawater eutrophication triggered local macrobiological experimentation in the 2100 Ma Paleoproterozoic Francevillian sub-basin. Precambrian Research 409: 107453, 1–17. DOI: https://doi.org/10.1016/j.precamres.2024.107453

El Albani A, Bengtson S, Canfield DE et al. 2010. Large colonial organisms with coordinated growth in oxygenated environments 2.1 Gyr ago. Nature 466(7302), 100–104. DOI: https://doi.org/10.1038/nature09166El Albani A, Bengtson S, Canfield DE et al. 2014. The 2.1 Ga Old Francevillian Biota: Biogenicity, Taphonomy and Biodiversity. PLoS ONE 9(6):e99438, 1–18. DOI: https://doi.org/10.1371/journal.pone.0099438

El Albani A, Mangano MG, Buatois LA, Bengtson S, Riboulleau A, Bekker A, Konhauser K, Lyons T, Rollion-Bard C, Bankole O, Lekele Baghekema SG, Meunier A, Trentesaux A, Mazurier A, Aubineau J, Laforest C, Fontaine C, Recourt P, Chi Fru E, Macchiarelli R, Reynaud JY, Gauthier-Lafaye F & Canfield DE 2019. Organism motility in an oxygenated shallow-marine environment 2.1 billion years ago. PNAS 116(9), 3431–3436. DOI: https://doi.org/10.1073/pnas.181572111

El Albani A, Konhauser KO, Somogyi A et al. 2023. A search for life in Palaeoproterozoic marine sediments using Zn isotopes and geochemistry. Earth and Planetary Science Letters 612:118169, 1–13. DOI: https://doi.org/10.1016/j.epsl.2023.118169

Fakhraee M, Tarhan LG, Reinhard CT, Crowe SA, Lyons TW & Planavsky NJ 2023. Earth’s surface oxygenation and the rise of eukaryotic life: Relationships to the Lomagundi positive carbon isotope excursion revisited. Earth-Science Reviews 240: 104398. DOI: https://doi.org/10.1016/j.earscirev.2023.104398

Janssen K, Mähler B, Rust J, Bierbaum G & McCoy VE 2022. The complex role of microbial metabolic activity in fossilization. Biological Reviews 97(2), 449–465. DOI: https://doi.org/10.1111/brv.12806

Javaux EJ & Lepot K 2018. The Paleoproterozoic fossil record: Implications for the evolution of the biosphere during Earth’s middle-age. Earth-Science Reviews 176, 68–86. DOI: https://doi.org/10.1016/j.earscirev.2017.10.001

Lekele Baghekema SG, Lepot K, Riboulleau A, Fadel A, Trentesaux A & El Albani A 2017. Nanoscale analysis of preservation of ca. 2.1 Ga old Francevillian microfossils, Gabon. Precambrian Research 301, 1–18. DOI: https://doi.org/10.1016/j.precamres.2017.0

Maxmen A 2010. Ancient macrofossils unearthed in West Africa. Nature News June 30, 2010. DOI: https://doi.org/10.1038/news.2010.323

NHM 2014. Experiment Life – the Gabonionta. Press release March 7, 2014. ORF 2014. „Gabonionta“: Sensationsfund in Wien. ORF.at March 11, 2014. https://wien.orf.at/v2/news/stories/2635417/

Ossa Ossa F, Pons M-L, Bekker A, Hofmann A, Poulton SW, Andersen MB, Agangi A, Gregory D, Reinke C, Steinhilber B, Marin-Carbonne J & Schoenberg R 2023. Zinc enrichment and isotopic fractionation in a marine habitat of the c. 2.1 Ga Francevillian Group: A signature of zinc utilization by eukaryotes? Earth and Planetary Science Letters 611: 118147, 1–13. DOI: https://doi.org/10.1016/j.epsl.2023.118147

Reynaud J-Y, Trentesaux A, El Albani A et al. 2017. Depositional setting of the 2·1 Ga Francevillian macrobiota (Gabon): Rapid mud settling in a shallow basin swept by high-density sand flows. Sedimentology 65(3), 670–701. DOI: https://doi.org/10.1111/sed.12398

Vosatka M 2014. Gabonionta, die kleinen Revolutionäre der Evolution. DerStandard March 11, 2014. https://www.derstandard.at/story/1392687847479/gabonionta-die-kleinen-revolutionaere-der-evolution

And yet another clash of Titans

 

JEHOVAH's technology vs. Darwinism

 Challenges to the Evolutionary Origins of the Glycolytic Pathway

Jonathan McLatchie

The purpose of cellular respiration is to convert the energy stored in glucose into adenosine triphosphate (ATP), the primary energy currency of the cell. Cellular respiration occurs in three main stages. Glycolysis involves the breakdown of glucose into pyruvate, producing a small amount of ATP. The citric acid cycle further breaks down pyruvate into carbon dioxide, generating NADH and FADH2. The final step of cellular respiration is the electron transport chain and oxidative phosphorylation, which produce a large amount of ATP, as well as water as a byproduct. In a series of articles, I will discuss features of cellular respiration that provide evidence of intelligent design. In this first installment, I will consider the problem of causal circularity as it pertains to the utilization of ATP in glycolysis.

The first step in cellular representation (glycolysis) is represented by the figure at the top. Glycolysis is ubiquitous across all living organisms. As shown in the figure, glycolysis involves the conversion of glucose, through a series of intermediates, to pyruvate. This pyruvate is then transported into the mitochondria where it is converted into acetyl-CoA by the enzyme pyruvate dehydrogenase. This process also produces NADH and releases one molecule of carbon dioxide (CO2). The acetyl-CoA then feeds into the citric acid cycle, where it is further oxidized, generating more NADH, FADH2, and ATP (or GTP).

Incremental Evolution?

Glycolysis has been proposed to be the first biochemical pathway to arise in evolution. Among the reasons for this are the fact that glycolysis is found ubiquitously across the tree of life (so may be inferred to have been present in the last universal common ancestor). Moreover, glycolysis is an anaerobic reaction sequence, and thus is consistent with the absence of oxygen in the primitive Earth environment.

There are, however, significant challenges to a proposed evolutionary origin of the glycolysis pathway. For example, the conversion of glucose to pyruvate involves as many as ten independent enzymes, typically 300 to 500 amino acids in length. It is extremely implausible that ten enzymes with complementary activities could have arisen at essentially the same time. But could the pathway have evolved incrementally, either forwards or backwards? It is generally rejected that glycolysis arose backwards (i.e., with pyruvate being initially available, then its precursor, etc.) since it was not the oxidized pyruvate, but rather sugar, that would have been present in the early Earth environment. Moreover, every intermediate between glycose and pyruvate is phosphorylated (i.e., has one or two of its hydroxyl groups replaced by phosphate). This involves a condensation reaction (where a water molecule is eliminated). Given the difficulties of this type of reaction, it is questionable whether the various intermediates could have emerged abiotically in high enough quantities to facilitate the origin of glycolysis.

The more popular view is that glycolysis evolved incrementally in the forwards direction. This hypothesis, of course, relies on the presumption that the intermediates could have served their own independent utility. However, since glycolysis is generally thought to have arisen extremely early — before additional utility of the intermediates could have arisen — it seems unlikely that the intermediates could have had independent usages.

Causal Circularity

Notice that the process of glycolysis consumes two ATP molecules — one at the glucose to glucose 6-phosphate step (catalyzed by hexokinase) and one at the fructose 6-phosphate to fructose 1,6-bisphosphate step (catalyzed by phosphofructokinase). The overall ATP yield of glycolysis is four (although many more ATPs will be produced later on), while two are consumed — making the net yield two ATPs. In order for ATP to be produced, ATP must first be consumed. This presents a causal circularity challenge to an evolutionary account of the origins of glycolysis. Strikingly, this causal circularity of ATP being required to manufacture more ATP appears to be ubiquitous across life.1 How could the process of glycolysis be established without an initial supply of ATP? Moreover, after the consumption of the first ATP, there are at least five additional steps (each involving its own enzyme) before any further ATP is produced), and nine before there is a net yield of ATP. Given that natural selection lacks foresight, this renders it extremely implausible that the enzymes early on in the glycolytic pathway could have served any benefit in the absence of the enzymes later in the pathway.

Excluding Water

Of the ten enzymes involved in glycolysis, six catalyze reactions that involve a phosphate group transfer. For a phosphate to react with a hydroxyl group of water to form phosphoric acid is just as energetically favorable as for it to react with the hydroxyl or a sugar or ADP. But this would be of no evolutionary advantage. Thus, water must be excluded from the enzymes’ active sites to prevent hydrolytic reactions from occurring. This is achieved through a mechanism involving conformational changes that resemble a “hinge motion.” Initially, the enzyme’s active site assumes an open conformation, allowing the substrate to enter. When the substrate binds to the active site, it induces a conformational change, causing the enzyme to undergo a “closing” motion, with the domains of the enzyme coming together, effectively shielding the active site. This motion not only secures the substrate but also excludes water from entering the active site.

This phenomenon underscores the engineering sophistication — and the degree of amino acid specificity — of these enzymes. Since the exclusion of water is absolutely critical to the occurrence of the appropriate reactions, there would be no use in having a partly formed enzyme (i.e., one that could catalyze the phosphorylation reaction but failed to exclude water). This casts further doubt on the ability of incremental adaptations to account for the glycolytic pathway.

Relationship Between Enzymes?

A further issue is that, if indeed glycolysis were one of the earliest metabolic pathways to evolve, one might expect that at the time of its origin there existed only a small repertoire of enzymes. Moreover, the compounds on which these enzymes act have similar structures. This might lead us to predict that the enzymes involved in glycolysis are evolutionarily related to one another. However, as Keith Webster notes:

Sequence and crystallographic data favor the divergent evolution of for example monophosphoglycerate mutase and diphosphoglycerate mutase, and possibly glyceraldehyde-3-P dehydrogenase and phosphoglycerate kinase from respective common ancestors, but convergence appears to have played a greater role in the development of all of the other 11 enzymes(Fothergill-Gilmore, 1986; Fothergill-Gilmore and Watson,1989). For example, there is no evidence of a common ancestor for any of the four glycolytic kinases or of the seven enzymes that bind nucleotides, with the exception of those mentioned above. Rather, it seems likely that the pathway resulted from the chance assembly of independently evolving enzymes and genes, probably in association with the co-evolution of other functions and linked pathways.

This seems contrary to what might be predicted on an evolutionary account of the origins of glycolysis.

Intelligent Design

Multiple challenges confront an explanation of the glycolytic pathway in terms of unguided evolutionary mechanisms. The complexity and engineering sophistication comport much better with the hypothesis of design. In particular, the causal circularity of ATP being required to make more ATP is difficult to account for by a stepwise evolutionary process. On the other hand, this sort of phenomenon is totally unsurprising on the supposition of the involvement of an intelligent mind.

Notes

Kun A, Papp B, Szathmáry E. Computational identification of obligatorily autocatalytic replicators embedded in metabolic networks. 

Genome Biol. 2008;9(3): R51.

Webster KA. Evolution of the coordinate regulation of glycolytic enzyme genes by hypoxia. J Exp Biol. 2003 Sep; 206(Pt 17):2911-22.

The Origin of Life : the simplified version?

 Is Assembling Life Like Assembling LEGOs?

Robert schedinger

I recently read Sara Walker’s new book, Life as No One Knows It: The Physics of Life’s Emergence. The book is addressed to a popular audience, and although the term is barely used, it is really about assembly theory in origin of life research. Walker asks questions like, What is Life? (with no definitive answer), and calls the origin of matter and the origin of life two hard problems in science. Walker mostly tackles the latter through her explication of assembly theory, but with questionable success. 

Illustrating with LEGO Blocks

Because the book is aimed at a popular audience, Walker has the difficult task of explaining technical concepts in ways accessible to general readers. Thus, she resorts to the analogy of LEGO blocks to illustrate how complex structures can be assembled by combining simpler structures through a process called selection. Two LEGO blocks can be combined in only a small number of ways. But as a LEGO figure grows larger, the number of ways to attach new blocks quickly inflates. Randomly attaching new blocks to a complex figure will likely not produce a useful or meaningful figure. But a process of selection at each step can cut a path through this inflating combinatorial space toward the creation of a complex and meaningful figure. 

According to Walker, this is how life originated. She writes:

The origin-of-life transition occurs when the combinatorial explosion of possible low assembly molecules gets constrained and funneled to select only a subset of possible molecules. Those are scaffolded to build more assembled objects, where those objects in turn build even more assembled ones. It captures the idea that it is objects building slightly more complex objects all the way down. As Lee [Cronin] sometimes says, to solve the origin of life all we need is to generate a simple machine that can build a slightly more complex machine, and so on. (163)

Unfortunately, Walker provides no clue as to what process does all the “constraining,” “funneling,” and “scaffolding.” And what characteristic marks the non-life-to-life transition if we don’t have a good working definition of life in the first place? Moreover, if Lee Cronin is successful in generating a machine capable of generating more complex machines, it will be Cronin’s intelligence standing at the head of this process. What undirected process would be capable of generating the original machine-generating machine? I came away from Walker’s book with far more questions than answers. 

Refreshingly Transparent

To Walker’s credit, however, she is refreshingly transparent on one crucial point. In a discussion of homochirality in organic molecules, she freely admits, “We do not know the mechanism by which this property first arose for the life we observe on Earth.” (173) She does go on to state her hope that assembly theoretic principles might eventually “shed new light on what has been a stubborn mystery.” (173) I wouldn’t bet the house on it. And without a naturalistic explanation for homochirality, one can never have a naturalistic explanation for the origin of life. 

One other stylistic feature of Walker’s book is worth mentioning. Against all literary convention, she insists on referring to other scientists by their first names after the first reference where she provides the full name. So, we are regularly treated throughout the book to references to conversations Walker has had with people like Paul, or Lee, or Andy, leaving the reader to scramble to remember that these are references to Paul Davies, Lee Cronin, and Andrew Ellington. I don’t know if she is trying to impress the reader by showing that she is on a first-name basis with all these scientists. But this stylistic decision can be confusing and undercuts the professionalism of the book (I’m surprised the publisher allowed it).

In all honesty, I wouldn’t recommend spending time reading Life as No One Knows It. Sara is well-versed in physics and chemistry, yet she is just as clueless on the origin of life as every other scientist trying to explain it in purely naturalistic terms.