In Integral Relational Logic, evolutionary hierarchy indicates the ontogenetic structure of generations of individuals, as they are born from their parents, during a billion years of sexual reproduction, as we see in family trees of ancestors and descendants.

The class diagram of such relationships contains very little information, showing just the single class of Person, with a parent-child relationship. Rather, we need an instance diagram, such as the hourglass tree view in Reunion, the family history program I use on my iMac and iPad.

However, to obtain a more complete picture of familial relationships, we need to interconnect these hierarchical relationships, as in this diagram, for instance.