The emergence of animal ecosystems during the late Ediacaran (~571-539 million years ago) was a pivotal episode in the evolutionary history of life. However, most of these Ediacaran organisms disappeared immediately before the Cambrian, in what may represent the first mass extinction of complex life. There are thus two key questions that will provide fundamental insights into the origins of modern ecosystems: 1) where do Ediacaran organisms fit in the tree of life? And, 2) what drove their extinction prior to the onset of the Cambrian? We will address these questions by combining new data collected during fieldwork with computer simulations performed on both individual organisms and whole communities. This project will improve knowledge of the early evolution of complex ecosystems, while at the same time pioneering the development of a rigorous new approach for examining how marine organisms evolved in response to moving fluids. We will work together with local school teachers to produce learning modules focused on 3-D modelling and fluid dynamics, suitable for communicating key evolutionary principals to students (16-18 years old) in the UK and USA.