The biological connection between a parent and a child: The relationships among individuals within a sexually reproducing species are known as "tokogenetic" relationships, and the graphical depictions of tokogeny are called geneologies or networks.

Tokogeny can also be described as the diachronic relationship through time between a parent and an offspring and therefore it is supposed to apply to asexual as well as sexual taxa, the reticulate (network) relationships among individuals.

Common characteristics in the tokogentic structure or system are called traits.