The breakdown products—glucose and fructose—are then imported into the cell and used to drive growth. If sucrose is in short supply and the density of single cells is low, the cells cannot capture enough of the glucose and fructose to initiate growth (upper panel). Under these conditions, mutations that cause the cells to form undifferentiated multicellular clumps (lower panel) confer an advantage, by increasing the local concentration of glucose and fructose available to cells. Selection for these mutations may lead ultimately to the evolution of multicellularity.
FIGURE CREDIT: IMAGES: [JOHN KOSCHWANEZ].