On the eve of animal evolution | Marine Biological Laboratory

Choanoflagellates, pictured above in the rosette colonies they are wont to form, are single-celled organisms that scientists believe represent one of evolution’s last stops on the way to animals. Just one spot over on the evolutionary chart, multicellular sponges, the earliest branching lineage of animals, appear. This piece considers the clues these pivotal nanoplankton could hold to understanding the origin of animals.