Brachiopod (image) Ohio University Caption New Ohio University research suggests that the rise of an early phase of the Appalachian Mountains and cooling oceans allowed invasive species to upset the North American ecosystem 450 million years ago. The study, published in the journal PLOS ONE, took a closer look at a dramatic ecological shift captured in the fossil record during the Ordovician period. Ohio University scientists argue that major geological developments triggered evolutionary changes in the ancient seas, which were dominated by organisms such as brachiopods, corals, trilobites and crinoids. This image shows one of the brachiopods under study, Glyptorthis. Credit David Wright Usage Restrictions Please credit David Wright. 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.