Nthe nineteenth century, theories of race moved from religious-based racism to:

During the 19th century, race moved from religious-based to scientific based. This era resulted in scientists trying to prove that some races are genetically superior to others.

This type of racism called on scientists to take data (like facial features, distance between body parts, shape of head) in order to analyze it. At one point, it was argued that blacks had similar head shapes to that of chimpanzees  and monkeys to prove their inferiority.

However, it is widely known now as a science based on false data, exaggerations, and lies in general.