Cambrian Explosion: oxygen not required (Introduction)

by David Turell , Monday, January 01, 2024, 18:13 (117 days ago) @ David Turell

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https://evolutionnews.org/2023/12/3-story-of-2023-textbook-wisdom-on-origin-of-multicel...

"a new study (Ostrander et al. 2023) by group of researchers from Denmark has overturned decades of evolutionary dogma and claims the exact opposite: “oxygen didn’t trigger multicellular organisms” (Anonymous 2023, UCPH 2023). What this study found was instead clear evidence of a lower oxygen content correlated with the Avalon Explosion of the Ediacaran biota. The authors summarize their surprising findings as: “Contrary to a classical hypothesis, our interpretations place the Shuram excursion, and any coeval animal evolutionary events, in a predominantly anoxic global ocean.” Co-author Christian Bjerrum commented “Specifically, it means that we need to rethink a lot of the things that we believed to be true from our childhood learning. And textbooks need to be revised and rewritten. So, if not extra oxygen, what triggered the era’s explosion of life? Perhaps the exact opposite” (Anonymous 2023, UCPH 2023). Some even went further and suggested to “forget everything you thought you knew about how life evolved on Earth” (Ralls 2023) because it “turns out we might be very wrong about how life arose on Earth” (Harrison 2023). (my bold)

"Incidentally, a few days ago I received a personal message from my paleobiologist colleague Dr. Ken Towe, a retired former senior scientist at the Smithsonian Institution, who had read a recent article of mine at Evolution News on the Cambrian Explosion (Bechly 2023). He suggested that he has found a solution to the problem of the sudden appearance of complex body plans in the Cambrian, which supports the biological and biochemical evolution needed to make the multicellular connective tissues and the strengthening required for the larger higher forms of life to suddenly appear. His hypothesis (Towe 1970, 1981, also see: Saul 2009) is basically that two entirely new amino acids (i.e., hydroxyproline and hydroxylysine), which are required for the formation of structural glycoproteins such as collagen in metazoans, could only form under oxygen rich conditions and that explains the late origin of complex multicellular life after the “boring billion” of only bacterial and protist life.

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"As we have just seen above, new research suggests that, contrary to seventy years of Darwinian consensus science, the appearance of multicellular life did not correlate with higher oxygen content but indeed with a lower one. Also, experimental research had previously challenged the so-called oxygen control hypothesis for the origin of multicellular life (Bozdag et al. 2021, News Staff 2021)

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"Here is what Professor Derek Briggs, a world-renowned expert on Cambrian fossils, has to say on this issue: “We now know that the sudden appearance of fossils in the Cambrian (541–485 million years ago) is real and not an artefact of an imperfect fossil record” (Briggs 2015). Likewise, Zhang & Shu (2021) admitted that “multiple sources of evidence are strongly suggestive of a real evolutionary event being recorded rather than an artifact of an imperfect fossil record.” Cabej (2020) put it even more clearly: “Nevertheless, now, 150 years after The Origin, when an incomparably larger stock of animal fossils has been collected, Darwin’s gap remains, the abrupt appearance of Cambrian fossils is a reality, and we are still wondering about the forces and mechanisms that drove it. Despite the fact that, from time to time, a small number of students have questioned the reality of the Cambrian explosion on the same ground as Darwin, today’s consensus is that Cambrian explosion is a scientific fact” (Linnemann et al., 2019). And, “The Cambrian explosion is real and its consequences set in motion a sea-change in evolutionary history” (Conway Morris, 2000; Nichols et al., 2006).

"the abrupt appearance of animal body plan disparity stubbornly remains an unsolved problem for Darwinism. However, the new research of Ostrander et al. (2023) points to an even bigger problem, which is the dubious scientific status of Darwinian evolutionary theory itself that arguably seems to be compatible with any conceivable observations and thus unfalsifiable and heuristically worthless. If more than seventy years of consensus endorsed increased oxygen as trigger of multicellular life, and then scientists simply cheer for the progress of science (Harrison 2023) when the exact opposite correlation is found, there is something fundamentally wrong with the theory. Demonstration of a grandiose failure of a theory may be scientific progress, but it certainly cannot be forged into a success for this very theory. Maybe it’s time to look for a new theory that better explains the empirical data instead of producing decades of fallacious research."

Comment: This research is quite specific, that the origin of the Cambrian was preceded by very anoxic oceans. Quote "Contrary to a classical hypothesis, our interpretations place the Shuram excursion, and any coeval animal evolutionary events, in a predominantly anoxic global ocean." https://onlinelibrary.wiley.com/doi/10.1111/gbi.12557 Darwin's hope to solve the gap has not happened.