A newly discovered species of single-celled choanoflagellates forms arrays of many individuals, which can rapidly morph from feeding mode (left, shown in false color) to swimming mode (right).
Thibaut Brunet
There’s not much to a choanoflagellate. But a new species of these single-celled organisms, animals’ closest evolutionary relatives (SN: 7/29/15), could provide crucial clues to a fundamental question in biology: How did solitary cells band together long ago to form multicellular coalitions capable of moving, hunting and hiding?
Most choanoflagellates live simple, solitary lives.