Figure 1

Dictyostelium discoideum has a multicellular development, the latter stages of which are shown in this figure. After aggregating by chemotaxis, the cells form a mound, differentiate into two cell types and then, over the next 12 hours, construct a fruiting body consisting of 80,000 viable spores on a stalk created by 20,000 dead stalk cells. D. purpureum has a similar development, except for an earlier formation of the stalk and the synthesis of a purple dye in the spore mass. Both species aggregate by chemotaxis toward sources of cAMP. The high synchrony of development makes these experiments possible. Image reproduced from [12]