Before we spend any more time bashing modern taxonomy it's worth noting that it is NOT based on evolution. Carolus Linnaeus was a Creationist who died two decades before Charles Darwins birth. The original definition of a species was "a creature created independantly by god", the modern system generally ammends this to a creature which is sexually issolated. With much debate over whether it must be unable or unwilling to reproduce. Kingdom, Phylum, Class, Order, Family & Genus were then decided on pure supposition but have proved a sensible framework for evolutionary studies.
Interestingly it was Linnaeus (Once again a creationist) who placed humans in the primate order.
In a letter to Johann Georg Gmelin dated February 25, 1747 (112yrs B4 Orgn Of Specs.)
Linnaeus wrote:
"It is not pleasing that I placed humans among the primates, but man knows himself. Let us get the words out of the way. It will be equal to me by whatever name they are treated. But I ask you and the whole world a generic difference between men and simians in accordance with the principles of Natural History. I certainly know none. If only someone would tell me one! If I called man an ape or vice versa I would bring together all the theologians against me. Perhaps I ought to scientifically",
He seems kind of scared to say what "he ought" around "the theologians".