Throughout the past several centuries, people have used the term to describe groups of people in much the same way it was used in past centuries to describe groups of animals. People with ancestry from a particular region of tend to share certain inherited similar features, resembling their parents. However, the children of parents with substantially different ancestral backgrounds often have an appearance that is intermediate between that of their two parents, and in subsequent generations, the offspring may vary. In part because of the obvious similarities between animals and humans for how traits are inherited, and in part because of cultural, political, and religious traditions, notinos of racial purity and superiority have surged and ebbed yet persisted, crossing the boundaries of culture, geography, politics , and time. They are still with us today, and some of the most insidious actions based on notions of racial supremacy happened not long ago.
Daniel J. Fairbanks