Chapter 2 in Race in North America covers the beginnings of the idea of race as it is thought of currently. Race as late as the 17th century was still a nebulous concept and was used to group individuals not by complexion but by status, temperament and generations among other things. Later assumptions of behavior were attached to race. Race was then used to refer to those who were non-European or, in the case of the Irish, non-English.
Evidence of the word race first appears in the Middle Ages in reference to animal breeding stock. The meaning evolved to be equitable with people/type/variety to classify the native populations in colonized areas. By the mid-1700s race had become an accepted means of categorizing non-European cultures because the definition now included hereditary traits.
Value judgments were attached to race in an effort to show non-Europeans as other, not pious or morally lacking. Also, since value was placed upon wealth, and wealth was necessary for personal freedom, those without wealth did not own their labor or their person. Since the purpose of colonization is to extrapolate the new countries resources, the human populations were seen as resources since they had no wealth, freedom or the right to personal ownership in the eyes of their colonizers. Race could then be used as a means of perpetual subjugation.