A study conducted 57 years before the publication of On the Origin of Species has been recognized as the first experiment on evolution. Unfortunately, the results were interpreted as indicating species do not change over time, possibly setting back progress by decades.
In the early 19th century, French scientist Jean-Baptiste Lamarck argued that species could change and turn into others, but proposed a mechanism now largely displaced by Darwin’s. Like Darwin, Lamarck faced fierce opposition to his theories, including from his colleague at the French National Museum of Natural History, Georges Cuvier.
Napoleon was interested in science and archaeology, and when he invaded Egypt he had his soldiers collect vast quantities of artifacts to be shipped back to France. The most notable was the Rosetta Stone, but the fortunes of war meant the Stone ended up in the British Museum.
Among the objects returned to Paris were two mummified birds, among the millions preserved by the ancient Egyptians in their worship of the god Thoth.
European scientists initially misidentified the birds as storks, but noticed differences between them and the birds they knew. This became possible evidence the birds had evolved in the 2,000-3,000 years in between.
Curtis describes how Cuvier recognized the mummified birds were not storks at all, instead resembling certain modern specimens in the museum that were yet to be classified. Cuvier named the species Numenius ibis, although we now know it as Threskiornis aethiopicus, or the sacred ibis.
Carefully comparing the beaks, bones, and coloring of the mummified and modern ibises, Cuvier demonstrated that no significant changes had occurred over thousands of years, bolstering his case for what he called the “fixity of species”.
Lamarck disputed these claims, arguing 3,000 years was insufficient time for evolution to produce noticeable changes, particularly in a constant environment. Cuvier hit back, arguing long time spans are made up of shorter ones, and if such a time span changed nothing, 100 times as long would produce 100 times nothing. He largely carried the day with his scientific peers, even driving home the point in his elegy after Lamarck’s death.
“This is a reminder that now, as much as ever, we need to be aware of confirmation bias, and the detrimental impact that dominant personalities can have on science,” noted Curtis.
Curtis told IFLScience that scientific historians have previously described the debate between Cuvier and Lamarck but missed the significance of the ibis study, particularly its place as the first experimental test of evolution. She said that while it was speculative to consider what might have happened if Lamarck had triumphed in the eyes of the era’s other leading scientists, such an outcome might have “made people feel safer exploring such ideas earlier, and we might have got further down the path.”
There were ironies for both scientists participating in the debate. Cuvier, Curtis said, was one of the first scientists to note the fossil record contained species that no longer existed, and the first to name an extinct species. In doing so, he laid important groundwork for evolution’s eventual triumph. Meanwhile, Lamarck attributed the lack of visible change in part to the consistency of the environment, despite usually espousing a form of evolution that did not require changing conditions if species were to transform.
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