Figure 1.

The foundations of multicellular cooperation and cheating. The evolution of multicellularity involved the bringing together of five foundations for cellular cooperation (inside pentagon), in a way that led to a major innovation in this history of life. These five foundations are resource allocation (e.g. circulatory systems), division of labour (e.g. development of specialized organs), the extracellular environment (e.g. skeletons), controlled cell death (e.g. tissues structures such as digits, neural structures) and proliferation inhibition (e.g. cell cycle control). Cheating in each of these foundations (outside pentagon) can disrupt multicellular cooperation, requiring the evolution of further controls in order to maintain effective multicellular function. These forms of cheating can either result from the loss of innovations that make multicellularity viable or from innovations that disrupt and exploit multicellularity through novel functions. Adapted from Aktipis et al. [4].