Answer: political or social racism grew out of biological racism (18century) and was introduced to social sciences in the mid-XIXcentury (social darwinism). Because of this societies started being interpreted according to organicist model. Some races became superior and other inferior, some were to grow or progress, others to stagnate or degenerate.
Explanation: Social and political racism is a part of what is called biologization of social sciences, merged with already existing anti-semitism and influenced all the social disciplines. At that time there was a hayday of colonialism and Darwinist evolutionary theory. Europeans started interpteting world cultures and societies according to these new tools. It was a natural evolution. This perspective was self-destructive much later....in the 20th century.