Fossil Calibrations for Select Groups (image) Field Museum Share Print E-Mail Caption This graph shows the beginnings of select groups of animals throughout time. Credit Courtesy of The Field Museum Usage Restrictions Must use credit line. 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.