Early Life's Explosion
The sheer enormity of new body plans and life forms that emerged 540 million years ago, during what's known as the Cambrian explosion, is evident in this simple but rich illustration. Contained in a paper on the origin of central nervous systems, it depicts the organisms that existed prior to the Cambrian explosion (left) and those that followed (right).
Citation: "Evolution of centralized nervous systems: Two schools of evolutionary thought." By R. Glenn Northcutt. 20 June 2012.
Image: R. Glenn Northcutt/PNAS (Larger image)