Saltatory Ontogeny and the Life-History Model: Neglected Processes and Patterns of Evolution

A single cell – an egg – cannot be in the same stabilized state as a differentiated multicellular embryo or reproducing adult. The entire ontogeny must, therefore, consist of a sequence of stabilized states. Ontogeny of a phenotype cannot progress gradually but is a saltatory homeorhetic system, proceeding via natural thresholds from one self organized state to the next, hierarchically ever more complex and specialized. The natural boundaries of ontogeny – the far-from-stabilized thresholds – represent also states when changes can be easiest inserted or induced, and especially in the early ontogeny, from the intervals where evolution (change) can occur. As a result, ontogeny can also be divided into distinct life-history intervals called periods, be it embryo, larva (infant, pup), juvenile, adult and senescence, each divided in turn into phases, and each of these into natural steps. It is left to the imagination of scholars in social sciences to find parallels of saltation in economics and history.