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.
What is hypodescent? Why is it important?
Hypodescent is the rule that automatically assigns the children of a mixed union or mating between members of different socioeconomic groups in the less privileged group. This is important to understand because it is how race is determined in the U.S. Because of hypodescent, race in the U.S. is fixed at birth and does not change. Also, due to the way hypodescent operates, the number of people classified as "black" or "Native American" is growing faster than the number of people classified as "white" because in order to be classified as white, both of your parents have to be "white." It is important to understand that this is not the only way in which race is assigned. Different cultures determine race in different manners.
Are all systems of human racial classification around the world the same?
No, because human racial classification is a cultural construction; there is no universal system of classifying race. Rather, each culture has its own way of determining race. Some systems are very similar, like the racial classification systems used in the U.S. and Japan, while others are different, like the one used in Brazil. For example, concepts of race in the U.S. and Japan are very rigid and fixed from birth. In contrast, race in Brazil is fluid and flexible. Race in Brazil is determined in part by an individual's parents, in part by an individual's phenotype, and in part by an individual's socioeconomic status. As result, a person's race in Brazil can change as they become wealthier or poorer. In the U.S. or Japan, a person's socioeconomic status does not affect their race.
Why is it important to understand that social race is a cultural construction?
It is important to understand that the distinctions made in the textbook between social and biological race are not just to make you have to learn two more definitions. Since human racial classifications have no basis in biology, they must be cultural constructions. By definition, cultural constructions are arbitrary in that they are created and maintained by each culture. As a result, cultural constructions are not fixed forever; rather they are dynamic and change over time and through space. For instance, are the notions of race found in the U.S. today the same as those that were in use 50 years ago? 100 years ago? 200 years ago? Are the notions of race found in urban parts of the U.S. today identical to the notions of race found in more rural parts of the U.S.? These differences exist because race is a cultural construct. The importance lies in the fact that as a cultural construction, race changes and can be changed. People actively use race and people can actively change how race is perceived. What role did Martin Luther King Jr. play in changing American attitudes about race? What role did Jesse Owens and Toni Morrison play in changing American attitudes about race?