The evolution of living organisms is shaped by the physical environment where they live. Different species operate at different spatial and temporal scales and to survive they have to adequately probe and respond to their surroundings. Microbes live in a world dominated by viscosity, imposing severe constraints on motility. I will focus on the biomechanics of collective motility in two systems of microorganisms where cells cooperate to elude these physical constraints: bacterial biofilms and fungal spore dispersal. Combining high speed imaging and fluorescence microscopy with theoretical tools borrowed from the continuum and statistical mechanics of complex systems, I will discuss how cells manipulate their physical environment as a survival strategy, and the threats to cooperation imposed by potential cheaters. Organisms living in a fluctuating physical environment must face uncertainty, which is a fundamental driver of biological behavior. I will conclude by discussing the physical constraints ensuing from stochasticity in the fluid dynamics of airborne dispersal.