 The other thread of genetic research that emerged attended to the evolutionary implications of Mendelian inheritance. Charles Darwin published On the Origin of Species in 1859, and the fact of evolution was widely recognized by 1900; however, the nature of the evolutionary process remained contested (Darwin 1859). According to Darwin, evolution was a very slow and gradual process, with natural selection favoring subtle differences between organisms (slightly longer legs, for example) that inclined one to be more successful at reproduction in some particular environment (entry:  Darwinism).  Mendel’s principles of inheritance, when they were hailed at the turn of the twentieth century, were thought by many geneticists to be incompatible with Darwinian evolution because Mendelian inheritance seemed more discrete (e.g., round or wrinkled peas, purple or white flowers), and so it was favored by scientists who advocated for a faster and more discontinuous process of evolution. Indeed, one of the reasons that Bateson so eagerly championed Mendel’s work was because he was a proponent of this less gradual interpretation (entries:  evolution;  fitness).