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Fossil Friday: Eozoön, the Dawn Animal Fallen from Grace

Photo credit: Wilson44691, Public domain, via Wikimedia Commons.

In the late 1850s the Canadian geologist William Logan, who as director of the Geological Survey of Canada mapped the geology of the country and authored the monumental Geology of Canada, discovered striped rocks from Precambrian limestone of eastern Canada, which he believed to be fossils of early life forms. He announced the discovery 1864 at a conference in Great Britain (Logan 1864, 1865), which immediately attracted tremendous interest and strong support by the British protistologist William Benjamin Carpenter. Famous geologist Charles Lyell commented that this represents “one of the greatest geological discoveries of my time” (Lyell 1864). Logan sent samples to his Canadian colleague John William Dawson (1865), who described the material as giant fossil protists, which he named Eozoön canadense, the dawn animal from Canada (also see Dana 1865). Dawson called it “one of the brightest gems in the scientific crown of the Geological Survey of Canada,” because at this time it was the earliest known evidence for life on Earth and “created a sensation in the geological community” (Adelman 2007).

Meet the Eozoönists

Most contemporary scientists did not doubt that Eozoön is a genuine fossil organism, with the exceptions of geologist William King and chemist Thomas Rowney from Queen’s College. These two skeptics, who did not believe in a biological origin of Eozoön, published a critique just a year after the original description and initiated one of the greatest scientific controversies of the 19th century. The supporters of the authenticity of the fossils, led by Dawson and Carpenter (1865), were called the Eozoönists, and both sides heavily relied on the scientific authority of their proponents and disputed the credibility of their opponents (Adelman 2007,  O’Connor 2023). German naturalist Otto Hahn (1876) supported the critical view of King and Rowney with a paper refuting the fossil status of Eozoön. Other critics were the British protistologist Henry Carter (1874a1874b, 1874c) and the German zoologist Karl Möbius (1878), who both disputed any relationship with known protists, as well as the British geologist Henry Johnston-Lavis, who described very similar structures from volcanic marble shot out of Mount Vesuvius in Italy (Johnston Lavis & Gregory 1894), which were clearly of inorganic origin and therefore considered by many as final nail in the coffin of Eozoön. Nevertheless, the controversy persisted, and as late as 1947 Eozoön was endorsed as a first life form in a high school biology textbook (Moon et al. 1947). Since the 1950s other supposed evidence for Precambrian life began to accumulate (Schopf 2000), so that Eozoön simply lost its crucial importance for a solution to Darwin’s most vexing problem of a “missing Precambrian history of life” (also see Stephen C. Meyer’s 2013 book Darwin’s Doubt).

The Rise and Fall of Eozoön

Several papers in the past decades reviewed the scientific history of the rise and fall of Eozoön (O’Brien 1970Schopf 2000Adelman 2007Wilson 2011Dolan 2023O’Connor 2023). Dolan (2023) recently showed that Eozoön “was never indisputably proven to be inorganic. Rather Eozoön simply faded away after its most ardent defenders died … To paraphrase a quote attributed to Mark Twain, the rumor of the death of Eozoön, announced with some authority at least three times, was each time, an exaggeration. King and Rowney believed that they had disproved the organic nature of Eozoön in 1866. Some 13 years later, Mobius clearly felt he had to show that Eozoön was not a fossil forminifera, as did Johnston-Lavis when he announced his discovery of Eozoön structures in volcanic ejecta in 1894.” 

Of course, there was a deeper reason why most scientists of Darwin’s era preferred to strongly defend Eozoön. This reason was clearly formulated by O’Brien (1970) in his review of the case:

… every aspect of nineteenth-century paleontology was scrutinized for its bearing on evolution …

There were two chief reasons for the persistence of the dispute. Most obvious and most important was the inability of early paleontology to settle the matter. The second reason, seldom stated by the disputants, was the significance of Eozoön in the larger issue of derivation of species. For, were Eozoön proved to be organic, evolutionists would be confronted with the most impressive of all gaps in the paleontological record, a gap that would give pause to even the most ardent evolutionist. On the other hand, if this gap were successfully explained or overcome by the finding of subsequent forms related to Eozoön, the evolutionists could rejoice in having found, at the earliest date of known animal life, the simplest form of life, a form reasonably akin to the “one primordial form” of Darwin’s speculation. In short, there was something at stake for both sides in the greater scientific controversy.

Darwin himself was interested in Eozoön and its promise for his position. He introduced Eozoön into the fourth edition of The Origin of Species: “After reading Dr. Carpenter’s description of this remarkable fossil, it is impossible to feel any doubt regarding its organic nature.” Darwin cited Eozoön in his famous tenth chapter, “On the Imperfection of the Geological Record,” as an indication that gaps in the paleontological record were being filled, and that as the origins of life were pushed back, natural selection became a more reasonable mechanism of evolution (Darwin 1866: 371).

Defending Eozoön 

Dawson very early defended the biological nature of Eozoön (Dawson 1865b), continued until the end of his life (Dawson 1901), and was never convinced by any of the conflicting evidence presented by his critics. He even published two books on Life’s Dawn on Earth (Dawson 1876, 1897), in which he claimed Eozoön to be the starting point of creation. Indeed, Dawson was an ardent anti-Darwinist and did not believe in the quickly spreading theory of evolution. Thus, he was not amused at all that Darwinists jumped on his discovery and embraced it as support for their theory. He wrote (Dawson 1876: 227):

There is no link whatever in geological fact to connect Eozoön with the Mollusks, Radiates, or Crustaceans of the succeeding [rock record] … these stand before us as distinct creations. [A] gap … yawns in our imperfect geological record. Of actual facts [with which to fill this gap], therefore, we have none; and those evolutionists who have regarded the dawn-animal as an evidence in their favour, have been obliged to have recourse to supposition and assumption.

In other words, Dawson thought that the “discovery of his ‘dawn animal’ had exposed the greatest missing link in the entire fossil record, a gap so enormous that it served to unmask the myth of evolution’s claimed continuity” (Schopf 2000Wilson 2011). What an irony, which also shows how very differently the same fossil evidence can be interpreted by distinguished scientists.

In modern paleontology it is still a very common phenomenon that fossils are over-interpreted by the scientists and over-hyped in the media as undeniable and unequivocal proof for Darwinian evolution. Whenever you come across press releases that boldly claim a new fossil rewrites the history of life, represents a long-sought transitional form or missing link, or proves the gradual evolution of certain organs and body plans, all alarm bells should ring. This is usually a clear sign that the scientists have gone far beyond an objective description of the empirical evidence and are driven by the desire to support evolutionist hypotheses. Apparently, since the time of Darwin and Dawson, some things have not changed much.