SELECTION BEYOND THE INDIVIDUAL. “However, unicells undergoing POD do not leave any direct descendants. Thus, in unicells, POD (with the possible exception of autophagy) may involve adaptation through function, and selection, at levels other than the individual organism.” (POD = programmed organismal death).
http://www.esciencecentral.org/journals/are-internal-death-promoting-mechanisms-ever-adaptive-2329-9002.1000113.pdf