"D. discoideum" is a slime mold, part of a branch that might have emerged from eukaryotic ancestors about a billion years before the present. It seems that they emerged after the ancestors of green plants and the ancestors of fungi and animals had differentiated. But, in addition to their place in the evolutionary tree, the fact that PCD has been observed in the humble, simple, six-chromosome "D. discoideum" has additional significance: It permits the study of a developmental PCD path that does not depend on caspases characteristic of apoptosis.