I have dark skin. My nickname is El Negro. They call me El Negro in Mexico because even in my country, the dark skin is evidence of Indian blood, a sign that one technically belongs to a third class. Even my grandmother had some kind of differentiation with me, because I was darker than my siblings.
There have only been about a half dozen genuinely important events in the four-billion-year saga of life on Earth: single-celled life, multicelled life, differentiation into plants and animals, movement of animals from water to land, and the advent of mammals and consciousness.