From the cell, to the organ, to the organ system, to the body, to the society, all systems have these 19 things (according to James Miller's "Living Systems"):
1. **Reproducer** - making similar-to-itself bits
2. **Boundary** - holds components together and protects from the outside
3. **Ingestor** - bringing in matter/energy across the boundary
4. **Distributor** - moves energy/material around within the system
5. **Converter** - changes inputs of one form into another
6. **Producer** - makes stuff
7. **Matter-energy storage**
8. **Extruder** - outputs products/waste from the system
9. **Motor** - move the system, or parts within it
10. **Supporter** - maintaining spatial relationships between system components
11. **Input transducer** - receives signals from outside the system & converts them for use
12. **Internal transducer** - converts signals from inside the system
13. **Channel and Net** - the transducer's communications network infrastructure
14. **Decoder** - interprets signals
15. **Associator** - carries out the 1st stage of learning, associating things.
16. **Memory** - carries out the 2nd stage of learning, storing associations
17. **Decider** - receives lots of inputs, generates main system control signals
18. **Encoder** - for preparing signals outside the system
19. **Output transducer** - for actually sending signals out from the system
All of these "living" system features can also be applied to a _business_, when viewed as a system.
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# More
## Source
- [[Just Enough Structured Analysis]]
## Related
- [[What is a System]]