Historical racism is based on lineage and common decent; it identifies a population with a common origin in history, but not a population with a fixed biological character; used to define nation states in Europe; expressed through national symbols, such as Nazi eagle, Aryan cross; believed in superiority of some nations over others.
Scientific racism believes we can all be characterized by race with certain physical traits, such as brain size, sloping forehead; there is a hierarchy of races; biology determines intelligence; some races need to civilize others providing a justification for colonialism.