Dodging the Main Issue in the Cambrian Explosion
Concerning the well-known and persistent problem of the Cambrian explosion, Stephen Meyer stated the issue as clearly and succinctly as possible in his best-selling book Darwin’s Doubt: “the origin of new biological information” (p. ix). He has repeated this issue in videos, interviews, debates, articles and speeches before and after 2013, the book’s publication date. Indeed, it was the central issue in Meyer’s Smithsonian paper that led to Richard Sternberg’s ouster in 2004. With scientists in the ID movement stating this issue continually for more than two decades, evolutionary biologists cannot claim ignorance of it. Yet to the present day, they dodge it. In three recent papers, we see how they talk about everything and anything but the issue: the origin of new biological information. Let’s consider these papers in order of publication.
Molecular Clock Fiddling
Last November, Philip C. J. Donoghue of the University of Bristol (mentioned by Bechly here) with three colleagues struggled to calibrate the Ediacaran and Cambrian fossil record to the “molecular clock” hypothesis (see my discussion of the molecular clock here). Getting these two data sources to fit has been a pervasive challenge along the entire evolutionary timeline. The abstract of their paper in Science Advances1 claims success, but ends with a quizzical statement:
Integrating across uncertainties including phylogenetic relationships, clock model, and calibration strategy, we estimate Metazoa to have originated in the early Ediacaran, Eumetazoa in the middle Ediacaran, and Bilateria in the upper Ediacaran, with many crown-phyla originating across the Ediacaran-Cambrian interval or elsewise fully within the Cambrian. These results are in much closer accord with the fossil record, coinciding with marine oxygenation, but they reject a literal reading of the fossil record.
By that, they mean that if you calibrate the molecular clock to certain fossils, they do not fit most of the other fossils. Is their conclusion as anti-empirical as it sounds? You be the judge:
Our results suggest that there was a radiation of metazoans beginning in the middle Ediacaran, with all major phyla originating by the late Cambrian (Fig. 5), although this may have taken a little under 100 Myr based on the maximum and minimum age estimates for all of the phyla, suggesting the “Cambrian explosion” was more drawn-out than a literal reading of the fossil record would suggest. Although crown-Metazoa originated in the Ediacaran, many of the crown-phyla did not originate until the Cambrian; Euarthropoda, Echinodermata, Ctenophora, Hemichordata, Rotifera, and Chaetognatha likely originated in the Cambrian, while Chordata, Cnidaria, and Mollusca have late Ediacaran origins.
What this means is that the Cambrian explosion is evident from the fossils, but you cannot trust the observational evidence — the “literal” reading of the fossils — to perceive the truth of evolution. Don’t believe your eyes. Belief in evolution requires the belief in the existence of ancestors. Since evolutionists cannot see them, they must infer their presence from the molecular clock. But since the molecular clock hypothesis is built on the assumption of evolution, this is circular reasoning.2
Nowhere do these four evolutionists address the main issue: the origin of new biological information. Score: Dodgers, 1. (No opponent score given, since they are playing against themselves. Darwin skeptics have been disqualified by fiat, so they watch the game from the sidelines and call fouls.)
Tracking the Explosion
The next paper, published in Current Biology3 this month, tries to tease out differences between animal tracks and environmental traces on an exposed benthic deposit in Canada that lies on the boundary of the late Ediacaran and “the onset of the Cambrian explosion.”
The Cambrian explosion was a time of groundbreaking ecological shifts related to the establishment of the Phanerozoic biosphere. Trace fossils, which are the products of animals interacting with their substrates, provide a key record of the diversification of the benthos and the evolution of behavioral complexity through this interval.
The seven authors accumulate “The most extensive ichnologic dataset compiled from any Ediacaran-Cambrian section.” They believe that their resulting matrix of ichnofossils (some interpretation was required) will help with “refining our understanding of the early stages of the Cambrian explosion.” Mentions of evolution: 15. Mentions of biological or genetic information: zero.3
Notice their choice of noun phrases to dodge the cause of all the novelty:
The Cambrian explosion was a time of groundbreaking ecological shifts related to the establishment of the Phanerozoic biosphere.
Score: Dodgers, 2.
Getting Permission to Evolve
The third paper by seven authors, mostly from the University of Edinburgh, was published in Science Advances a few days later5. A refinement of the old Oxygen Theory for the Cambrian explosion (here, here), this new paper presents the notion that “Low oxygen but dynamic marine redox conditions permitted the Cambrian Radiation.”
The team inferred oxygen abundances and fluctuations on the Siberian Platform by proxy measurements. Surprise; the earliest Cambrian body plans were not dependent on oxygenation.
Whether metazoan diversification during the Cambrian Radiation was driven by increased marine oxygenation remains highly debated. Repeated global oceanic oxygenation events have been inferred during this interval, but the degree of shallow marine oxygenation and its relationship to biodiversification and clade appearance remain uncertain. To resolve this, we interrogate an interval from ~527 to 519 Ma, encompassing multiple proposed global oceanic oxygenation events…. We document primarily dysoxic water column conditions, suggesting that early Cambrian metazoans, including motile skeletal benthos, had low oxygen demands. We further document oxygenation events coincident with positive carbon isotope excursions that led to modestly elevated oxygen levels. These events correspond to regional increases in species richness and habitat expansion of mainly endemic species, offering a potentially globally applicable model for biodiversification during the Cambrian Radiation.
By stating without dispute that “A causal relationship between increasing shallow marine oxygenation and the Cambrian Radiation has long been proposed,” they essentially agree with the Oxygen Theory. Only the degree of oxygenation needed their clarification: “but it is not clear whether oxygen availability rose progressively through this interval and, if so, how this promoted biotic innovation and the radiation of early metazoans.” In other words, they want to answer how much oxygen was needed to trigger the explosion. You can’t just add oxygen. You have to add the right amount of oxygen. Then, bang!
One novel twist in their hypothesis is that evolution is permitted with or without oxygen; but with it, animals can move around. More noun phrases conceal their notion that oxygen gives animals permission to evolve. It enables them. It promotes them.
There has been much debate as to the actual drivers of an evolutionary response to oxygenation. Rising oxygen levels (potentially driven by increased productivity and organic matter burial) may have deepened the redoxcline, thereby extending habitable water depths. Enhanced oxygenation may also have enabled the evolution of more metabolically costly ecologies such as mobility and carnivory, as well as the ability to produce skeletal hard parts, thus promoting animal-sediment mixing and evolutionary escalation. Conversely, the presence of shallow marine anoxia itself might have formed physical barriers to dispersal and, thus, dynamic redox variability over evolutionary timescales may have promoted reproductive isolation and speciation.
Oxygen is like a ticket to ride. With oxygen, animals are permitted to evolve and swim. Without it, they have to stay put and evolve in place. These authors continue using other synonyms for permission: oxygen facilitates evolution; it makes animals able to expand and diversify. They almost catch themselves thinking the notion is crazy.
While a rise in oxygen levels has been suggested to facilitate the evolution of costly ecologies, it does not offer a definitive mechanism for the origination of new clades or the appearance of key evolutionary innovations, such as a biomineralization, bilaterality, and segmentation, but may rather provide a viable mechanism by which existing metazoan clades are able to expand their habitat range and so diversify.
Translation: Oxygen didn’t cause the Cambrian explosion. It just gave animals their “get up and go.” What did cause the Cambrian explosion, then? No answer.
Evolution gets 11 mentions by this team; biological or genetic information gets (again) zero. Score: Dodgers 3.
Until the Darwinians address the main issue in the Cambrian explosion, the expelled opposing team needs to keep shouting to the Dodgers through bullhorns from the sidelines, “But what about the origin of biological information?”
Notes
Carlisle, Donoghue et al., Ediacaran origin and Ediacaran-Cambrian diversification of Metazoa. Science Advances, 13 Nov 2024 (open access). DOI: 10.1126/sciadv.adp7161.
“There is no shortage of rhetoric that pitches molecular clock methodology and the fossil record as opposed and incompatible, but, given that molecular clock analyses are usually calibrated using fossil evidence, this is self-evidently false. Molecular clock methods provide a means of interpreting the fossil record in establishing a timescale for evolutionary history and, hence, they are in tension only with alternative approaches to inferring evolutionary time from the fossil record [like ID?]. There can be no doubt that the fossil record requires interpretation since it can be demonstrated intrinsically to be an imperfect temporal archive of evolutionary history.” Translation: Because evolution requires ancestors, and fossils do not provide them, we have to infer their existence without literal fossil evidence by “interpreting” the molecular clock (which assumes evolution).
They mention “novel architectural designs in ichnotaxa” but explain them as a “novel evolutionary event”— which sounds like, “Bang! New body plans! No intelligence allowed.”
Gougeon, Minter et al., Environmental and evolutionary controls in animal-sediment interactions at the onset of the Cambrian explosion. Current Biology, 20 Jan 2025 (open access). DOI: 10.1016/j.cub.2024.11.028.
Alexander, Wood et al., Low oxygen but dynamic marine redox conditions permitted the Cambrian Radiation. Science Advances, 24 Jan 2024 (open access). DOI: 10.1126/sciadv.ads2846
