The dynamics of multi-cellular coordination in a living fossil

The tradeoff between stability of form and sensitivity to environment is central to the emergent dynamics of living systems. At the organism scale, one of the most successful strategies for addressing this challenge is the integration of a nervous system with complex signal processing capabilities. Informed by the perspective of a true living fossil, we study the physical constraints on multicellular collectives which existed before the nervous system. Through joint experimental study of the phylum placozoa – an early diverging sister group to all animals with no muscles or neurons – and agent based numerical work, we investigate the delicate interplay between sensitivity and stability in a parsimonious model (an active elastic sheet) calling upon concepts from active matter and embodied computation. We find that through local rules alone multicellular collectives can generate long-wavelength stability without compromising organism-wide sensitivity to local inputs. We describe a low-dimensional representation of organism scale dynamics in the form of a simple quasi-particle description. Finally, we demonstrate these the utility of these results in the context of behaviorally relevant settings including: local-global foraging, and tribotaxis (ascending frictional gradients).