Each one of those tiny systems is the basic building block for all other systems. Each hydrogen atom is directly connected by origin to the birth of the Universe. This is what it means, in systems theory, to say that everything is connected.
Let's go back to my rule of thumb: The bigger the system the longer the time-frame. I keep saying that humans occupy the middle ground. The reason is because it took the universe seventeen billion years to produce us. We are young, we are infants compared to almost everything else but our own artefacts. Some say humans evolved one half million years ago. I mark the dividing line at two million years, with the first evidence of Homo Erectus.
One knows a system by observing its behaviour and its boundaries. In order to better understand the Human System, we ought to know as much as possible about when it began and how it began. Then we can better distinguish it from other kinds of living systems.