Bridge Species Lead Expansion from Tropics (image) University of Chicago Share Print E-Mail Caption The University of Chicago's David Jablonski is presenting new evidence that most evolutionary lineages started in the tropics and expanded outward in a process driven by what he and his colleagues call "bridge species." Credit NASA Visible Earth Usage Restrictions News organizations may use this image in connection with reports about the research of David Jablonski and his associates. Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.