I will preface this question by saying I have not read Nietzsche extensively. The one exception is his 'Genealogy of Morals', a recent read of mine, twice actually.
I always assumed Nietzsche's ideas of "the will to power" and the "Ubermensch" were inspired by Darwin's earlier writings, but I've since heard others say that Nietzsche was actually very critical of Darwinian Natural Selection (e.g. "Nietzsche's Anti-Darwinism" by Dirk Johnson). Can anyone save me reading books such as Jonhson's and explain: is there a clear consensus on whether Nietzsche actually understood Darwinian natural selection, and furthermore if he saw his own philosophy as supportive or rather as doing battle with it?