Fig. 1

Macroevolutionary Dynamics when \({R}_{in}=5\). Each cell is assumed to have a small probability of mutating to a cell of the opposite type. Under this condition, and when \({R}_{in}=5\), a single unstructured population or group will episodically transition between an A-type population with \(\pi =1\) and an S-type population with \(\pi =0\). Mutants of both types arise randomly (as indicated by vertical lines) and are usually eliminated. When fixation does occur, it does so very quickly due to the small size of the population, \({N}_{cap}\left(\pi =0\right)=16\) S-type cells and \({N}_{cap}\left(\pi =1\right)=100\) A-type cells. The population is therefore bistable but spends more time in the S-type state due to the fitness deficit suffered by A-type cells