Fig. 4. A schematic illustration of how morphostatic and morphodynamic mechanisms have different variational properties. A simple change in tissue growth does not affect induction (red) and the resulting pattern in a morphostatic system because only growth of initially induced territories is affected, resulting in slightly blunter or sharper features. In morphodynamic mechanisms small changes in growth can alter induction of new territories (Fig. 3), resulting not only in blunter or sharper features, but completely altered patterns. Morphostatic mechanisms would require large changes in induction of territories in order to produce comparable change, particularly in the case of positional information systems where each new territory would require a unique signal or signal concentration. In general, morphodynamic mechanisms can be hypothesized to produce more disparate morphological outcomes than morphostatic mechanisms.