Beginning in the eighteenth century, naturalists began to express doubts about the strict species fixity advocated by Linnaeus early in his career. Some of these naturalists entertained the possibility that species could be naturally derived from other species. During the pre-Darwinian period, numerous versions of the concept of evolution appeared, many of which were derived from the emerging field of comparative anatomy. Linnaeus himself, by the sixth edition of Genera plantarum, argued that species were derived from created organisms that were different from modern species (see Koerner, 1999). Robert Knox (1855), an anatomy lecturer from Edinburgh, proposed that species could evolve within genera but that the genera were fixed. Even the staunch Darwinian opponent Richard Owen advocated a kind of evolution by natural law called metagenesis (see Desmond, 1982).

In Origin, Darwin did not compare his evolution model with the rich variety of evolution and creation models available in his day. He instead critiqued a narrow view of species fixity. Darwin probably derived his view of species fixity from Lyell’s (1832) Principles of Geology, which he read during the Beagle voyage. After returning to England from that voyage, Darwin formulated his theory of evolution. It therefore should come as no surprise that Darwin’s (1859) concept of “creationism” closely resembles Lyell’s concept of strict species fixity. Probably as a result of Darwin’s Origin, even today creation science is often understood to mean extreme species fixity (e.g. Futuyma, 2005)….

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