These processes of evolution are responsible for the partitioning of mankind into different groups. However, there is no way of studying human raciation without studying the different cultures. For example, selection is for reproductive success. However, social systems and culture mostly determine the reproductive success in humans. However, some working individuals may feel that they do not have time to offer to their children would chose birth control methods to prevent pregnancy.
Migration depends on the economy, welfare, shelter, and transportation available to a society.
Mutations can even be affected by technology in the modern era due to the society's dependence on pharmaceutical drugs. Thus, genetic theory emphasizes the importance of culture as the major factor in the evolution of man. We must study man both as a biological and social organism and put together cultural as well as archeological aspects. Selection plays the primary role in the creation of racial differences. The differences in morphologies we observe in times past have been adaptive.