Darwin and the Origin of Species
After twenty years of hesitation, Charles Darwin published the argument that species were not created in fixed form but descended, with modification, through natural selection — that the variety of life could be explained without design. It reorganized biology and unsettled the account of human origins most Westerners had been raised on. His idea was also swiftly and grossly misapplied to human societies to justify colonial rule and racial hierarchy, a distortion he did not intend and which the science does not support.
A belief system rises, spreads, institutionalizes, and then schisms — changing the rules people accept as legitimate.