To sum up, if you have all of the following properties: Entities that replicate; Substantial variation in their characteristics; Substantial variation in their reproduction; Persistent correlation between the characteristics and reproduction; High-fidelity long-range heritability in characteristics; Frequent birth of a significant fraction of the breeding population; And all this remains true through many iterations . . . Then you will have significant cumulative selection pressures, enough to produce complex adaptations by the force of evolution.
