What is the difference between Models of Environments and Models of Systems?

I do understand Models of Systems and its implications but is unclear on Models of Environments. Let me it a try...Models of Environments are bounded by time and spaces, and do not have cause-effect relationships while Models of Systems do. Models of Systems reside within an environment.

E.g. Humans - a Model of Systems can learn within the classroom environment. And it is clear that human cannot be a model of environment. In this case, the classroom is the model of the environment and professor can be the model of expert behavior.

Could anyone provide more insight on the difference, pls?