To consider the many entities and processes in the world as systems, we need to mark a boundary between the system concerned and its environment. If we want to see a family as a network, for example, we could separate family members from the schools, neighborhoods, and places of work in which they regularly participate. When we were to see a cell as a system, the cell wall may be the boundary. Remember that when viewed from another angle, the device environment may be other systems. Boundaries of systems-environment can be physical or mental.
Open versus closed systems: certain systems are relatively closed, which reduces the impact their environments have on their operations to a minimum. In contrast, more open systems can change greatly, depending on their environment’s inputs. For instance, a small company is far more an open system than a car engine: the company is always developing and changing to survive, while the engine must remain the same to function properly.
Self-contained: One feature of the systems is that the systems comprise all processes and components needed for their different functions. Of course, nearly all systems take some environmental inputs (or other systems) and transform them into outputs. However, healthy systems can perform their functions self-contained (based on environmental inputs and return to the environment).
Adaptive: Some systems with greater complexity, such as biological and social systems, are capable of adapting to changing environmental conditions. In other words, they can often adapt and survive. They even prosper, even if the environment changes over time (i.e., macro-weather patterns, types of food, changes in other social systems, etc.).