Table 1. PCD and ETIs. PCD plays five key roles in the three ETIs discussed in this manuscript. For example, in the first instance, in eukaryogenesis PCD plays a role in the formation of cooperative groups by facilitating resource-sharing between individuals. In division of labor in eukaryogenesis, PCD plays a role in organellar specialization (see the text for further details).

The role played by PCD in...	Eukaryogenesis	Multicellularity	Eusociality
The formation of cooperative groups	Resource sharing	Resource sharing	Sterility in workers is required for the mediation of conflict, division of labor and mutual dependencies
The division of labor	Organellar specialization	Propagation and dispersal
Communication	Signaling cascade in PCD	Infochemicals
Conflict mediation	Death of the group	Death of uncooperative cells; genetic transfer
Mutual dependencies	Reliance on shared resources	Recycling of nutrients