ABANDONING INDIVIDUAL LIFESTYLES. “In each of these transitions, a group of individuals that could previously replicate independently joins together to form a new, more complex life form that can only replicate as a whole. For example, genes come together to form genomes, cells join together to form multicellular organisms, and multicellular organisms join together to form eusocial societies.”
http://www.sciencedirect.com/science/article/pii/S0960982213005678