Extended Data Fig. 3: Sensitivity of the simulation results depending on the value of the amplitude of the demographic noise.

Starting with a simulation identical to the one in Procedure 7, we repeated it with two different magnitudes of the noise amplitude σ: a,b, images of three replicas of a colony simulation (a), and plot of the total biomass change with time of the three replicas simulations with σ = 0.01 (b); c,d, Images of three replicas of a colony simulation (c), and plot of the total biomass change with time of the three replicas simulations with σ = 0.001 (d). A finalized result of a simulation study in presence of noise should be averaged over several replicas of the stochastic simulation. The change of the noise amplitude, however, may have a substantial effect of the growth rate and the final morphology. The value of the noise amplitude should be chosen to best represent an experimental result.