My point is why would Evolution allow humans to be the only species capable of intelligence. There even isn't any variety of humans that possess such distinct physical attributes to help them in nature. Humans may have different skin tones, hair color, and facial distinctions, but they don't have anything to distinguish themselves from each other as another pending species in the acclaimed evolutionary chain. Why? Evidently, there is no reason why these natural processes would develop if the organisms have already been residing in nature at a state of environmental equilibrium.