Diversity vs. Morphospace (image) Virginia Tech Share Print E-Mail Caption Scientists have recognized three Ediacara assemblages that lived between 575 and 542 million years ago. These are in geochronological order, the Avalon, White Sea and Nama assemblages, all of which preceded the Cambrian explosion of animals. The left panel shows that number of genera (black line) and how they are dissimilar from each other (gray line) in the three Ediacara assemblages. The right panel shows morphospace occupation of the three Ediacara assemblages. Although there are fewer genera in Avalon than latter assemblages, Avalon fossils occupy the full range of Ediacara morphospace, indicating an explosive evolutionary pattern (the Avalon explosion) similar to the Cambrian explosion of animals that occurred about 542 million years ago. Credit Shuhai Xiao, associate professor of geobiology at Virginia Tech Usage Restrictions with information about the research reported in Science 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.