David Severson, University of Notre Dame (IMAGE) University of Notre Dame Caption David Severson, professor of biological sciences at the University of Notre Dame. Credit Barbara Johnston/University of Notre Dame Usage Restrictions Must credit the University of Notre Dame. License Licensed content 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.