Biological system

On the micro to the nanoscopic scale, examples of biological systems are cells, organelles, macromolecular complexes and regulatory pathways.

[3] The enumeration of the principal functions - and consequently of the systems - remained almost the same since Antiquity, but the classification of them has been very various,[2] e.g., compare Aristotle, Bichat, Cuvier.

[4][5] The notion of physiological division of labor, introduced in the 1820s by the French physiologist Henri Milne-Edwards, allowed to "compare and study living things as if they were machines created by the industry of man."

Inspired in the work of Adam Smith, Milne-Edwards wrote that the "body of all living beings, whether animal or plant, resembles a factory ... where the organs, comparable to workers, work incessantly to produce the phenomena that constitute the life of the individual."

In more differentiated organisms, the functional labor could be apportioned between different instruments or systems (called by him as appareils).