Social stratification refers to the arrangement of individuals into divisions of power and wealth within a society. There are four main types of social stratification: slavery, caste, clan, and social class. A caste system determines status by birth and is lifelong, while a clan system links individuals to extended networks of relatives where status depends on lineage. Social class is based primarily on money and material possessions, dividing society into upper, upper-middle, lower-middle, working, and lower classes.