What is race?
The textbook distinguishes between two kinds of race: biological and social. A biological race is a geographically isolated subsdivision of a species that will eventually evolve into a new species if it remains isolated long enough. Some biologists use the term race to refer to breeds of domesticated species like dogs, cattle, corn, wheat, etc. In this sense, a single species will consist of a series of different breeds that have been carefully selected, bred, and maintained by humans for generations. Human populations have not been isolated long enough to develop races, nor have we ever experienced the controlled breeding like that which has created the various dogs, horses, corn, etc. As a result, human physical and genetic variation is not distributed into discrete populations marked by abrupt shifts in gene frequencies. Rather, human physical and genetic variation is distributed along gradual shifts or clines. This means that there are no human races. A social race is a group that is assumed to have a biological basis but is actually defined in a culturally arbitrary manner. This means that each culture has its own concepts of what race is as demonstrated in the textbook's discussion of race in the U.S., Japan, and Brazil.