Actually Darwin didn't know anything about random mutations, as in fact he didn't know about DNA or even genes. The Origin of Species is about observed results:

Actually Darwin didn't know anything about random mutations, as in fact he didn't know about DNA or even genes. The Origin of Species is about observed results: "descent with modification" rather than about mechanism. In any case, I'm not too sure about the scientific community being so easily accepting of Darwin. It's true that evolution (that is, the gradual changes in the characteristics of populations) was nearly universally accepted relatively quickly, but natural selection as a mechanism was not. In fact, for some decades in the late 19th and early 20th centuries natural selection was widely regarded as a minor contributor to evolution. This was not a matter of anyone believing that natural selection didn't occur, but simply an argument over the relative magnitudes of different forces. Alternative drivers of evolution included neo-Lamarckism. Notably, estimates of the age of the Earth at the time were very much lower than our current ones and many scientists believed (correctly) that natural selection was too slow a process to have produced the variety of life observed over a 10-100 million year timespan.