Bugs do it

...co-operate and cheat, that is:

An increasing body of empirical evidence suggests that cooperation among clone-mates is common in bacteria. Bacterial cooperation may take the form of the excretion of “public goods”: exoproducts such as virulence factors, exoenzymes or components of the matrix in biofilms, to yield significant benefit for individuals joining in the common effort of producing them...Moreover,...this synergism opens up a remarkably rich repertoire of social interactions in which cheating and exploitation are commonplace.

-- from Czárán T, Hoekstra RF, 2009 Microbial Communication, Cooperation and Cheating: Quorum Sensing Drives the Evolution of Cooperation in Bacteria. PLoS ONE 4(8): e6655. doi:10.1371/journal.pone.0006655

In the big picture, co-operation prevails. As Richard Fortey puts it, most of history has been conducted inside bacterial mats:

Sealed in slime from the cruelty of ultraviolet radiation, mats formed mounds, and columns, and pillows, and fingers; mats formed great cones in the deeper sea, the like of which have not been seen on Earth for 1,500 million years. Ultimately, mats maketh man.