Implicitly, the project of biomaterials and biomimetics considers structures in the topologically extracellular space of organisms: beetle carapace, feathers, butterfly wings, and wood are all extracellular materials. Our work seeks to make this implicit assumption explicit, and understand the material pattern formation that imbues function in these materials via equilibrium thermodynamic theories.  This talk will look at two pattern-forming biomaterial systems, plant pollen and squid lenses, in which the relevant pattern and function emerges from equilibration of biological components in the extracellular space.  Squid lenses have evolved to explore the patchy particle phase diagram, while pollen patterns form from a phase transition modulated by membrane elasticity.  Quantifying the evolution of these systems can provide further insight into molecular function, which can in turn inform efforts to realize these principles in engineered systems.