Describe symbolism in The Mismeasure of Man by Stephen Jay Gould

In Measuring Bodies, recapitulation is the theory based on tracing mankind back to the apes as they tried to construct a tree of life. "Recapitulation also provided an irresistible criterion for any scientist who wanted to rank human groups as higher and lower. The adults of inferior groups must be like children of superior groups, for the child is a symbol of a primitive adult ancestor. If adult blacks and women are like white male children, then they are living representatives of an ancestral stage in the evolution of white males.