Morphogenesis (the development of form) requires coordinated signal trafficking and cross-talking at different temporal and spatial scales among all levels of organization. This coordination can be experimentally 'dissected' into its component parts but not without a significant loss of information, since the logic of 'one signal, one response' is unjustified. However, a survey of recently published biological networks indicates that, with varying degrees of success, each can be modeled as a logic circuit supervising the operation of one or more signal-activated subsystems. This modeling approach can redact and simplify complex morphogenetic phenomena and allows for their aggregation into larger more global networked responses. The evidence for this conceptualization is provided and reviewed in terms of signal trafficking and cross-talking across networks associated with some important morphogenetic phenomena, e.g., auxin-mediated cell expansion, entry into different cell cycle phases, and floral organ morphogenesis.

Key words: control systems, gene networks, morphogenesis, plant hormones, signal transduction