Traitorfish
The Tighnahulish Kid
While the idea that Europeans were more highly evolved was present in that period, you may be misguided in your attribution of such beliefs of Darwinism; much as it is forgotten today, evolution was an established idea before Darwin's time (indeed, his grandfather was a proponent of such, in the form of much more linear models (which often left a comfortable amount of room for "intelligent design" of some sort). Darwinism was noted at the time as radically challenging these models- the very models which ordained the European as the natural and inevitable pinnacle of life- by suggesting an essentially randomly, amoral pattern to evolution and, importantly, suggesting that adaptation to an environment dictated the success of a species or "race" of humans. Darwinism suggested that the African and European were both adapted to their own immediate natural environments, not that either was functionally, let alone morally superior to the other. Darwin himself opposed this school of thought- already well established at the time, and not necessarily drawing on the principal of biological evolution- and deeply resented the appropriation of his purely mechanical explanation to serve political ends.That would disqualify most rulers of our history, you know, and the whole British Empire while we are at it (they pretty much believed that Darwinism _proved_ that Brits are the peak of human evolution and thus have the right to rule over the lesser people, such as Africans who were less than wildmen in their eyes).
When you get down to it, the British ruling class believed that they were entitled to rule over "savages" simply because they were able to, through violence and coercion, much as they ruled over their poorer countrymen. Whatever pretensions they dressed their brutality in, it was never anything more.