Multicellularity

Theories about how animals became multicellular are shifting as researchers find greater complexity in our single-celled ancestors.

A single genetic change and some clever geometry show how single-celled organisms can band together to form cooperative multicellular entities.

Bacteria may have helped single-celled organisms make the leap to multicellular animals.

An interview with the developmental biologist Cassandra Extavour on the origins of multicellular organisms and the evolution of cooperation.