These simulators explore the core mathematical models of Ecology. Several received top ratings from JARS and MERLOT. Some look dated now, and some were abandoned around 2001. But at the time, this was ground-breaking work.
One of our first semesters teaching with CourseWare, back in the late '90's, was a cross-listed undergrad-graduate course. The undergrads were taught modeling with CourseWare. The grad students went deeper, programming the models themselves. It was soon clear to the grad students that the undergrads had it easier. And worse, the undergrads learned the material much better - they blew the grad students away on tests. After that, the students all used the CourseWare.