Evolutionary transitions in individuality

Evolutionary transitions in individuality are events in which groups of previously independent replicators become new evolutionary individuals: genes into chromosomes, prokaryotic cells into eukaryotic cells, single cells into multicellular organisms, solitary organisms into societies.

The framework

John Maynard Smith and Eörs Szathmáry organized the history of life around this sequence in The Major Transitions in Evolution (1995). Each transition changes how hereditary information is stored and transmitted, and each raises the same two questions: why do the parts cooperate, and what stops a part from defecting?

What a transition requires

Leo Buss argued in The Evolution of Individuality (1987) that the obstacle is conflict among cell lineages, and that