Control across scales: Signals, information, and adaptive biological mechanical function

Biological systems perform an astonishing array of dynamical processes—including development and repair, regulation, motor control, sensing and signaling, and adaptation. Powered by the transduction of stored energy resources, these behaviors enable biological systems to coordinate functions, achieve specific outcomes, and maintain stability far from thermodynamic equilibrium. These behaviors span orders of magnitude in length and time: from nanometer-scale molecular motors driving morphogenesis to hundreds of kilometers during seasonal migrations, and from millisecond reflexes to millennia of evolutionary adaptations. While physical forces govern the dynamics and interactions of biological systems, they alone do not determine how living systems sense, decide, adapt, and, ultimately, control their dynamics. Here, we argue that control theory provides a powerful, unifying framework for understanding how biological systems regulate dynamics to coordinate mechanical function across length and timescales far from equilibrium.