When I think of biological systems I go back to 7th grade biology and recall that the human body has the following systems. I shall further draw analogies as to how these systems are directly replicated into buildings to make a healthy building. This is different from biomimicry (like the shape of a bullet train), because this is a direct analogy, not an indirect borrowing of a theme.
Skeletal System: These are the foundational iron structure (please correct my lack of jargon) or in the case of mass timber buildings, the mass timber
Muscular System: The iron bars give support, but they need strength in the form of poured concrete or concrete blocks that are placed around
Respiratory System and circulatory system: The HVAC system of the building is the respiratory system, with the air handler taking the role of the lungs, and the circulation of the air through shafts in the building being the blood vessels. The veins (bad or deoxygenated blood) carry the return air, and the arteries (good or oxygenated blood) carry the supply air
Nervous System: The electrical systems of a building are the nervous system (both of them work on electrical impulses and flow!). There is not much common except this. The nervous system is also responsible for the feeling sensation, which has a loose connection to the fact that even in buildings, stimuli is observed in places where there is light/plug-loads
Digestive and Excretory System: The plumbing system of a building is clearly the digestive and excretory system. It is responsible for the inflow of liquid, the functions within the building, and the responsible outflow of it.
Reproductive System: The one system that much more differentiates the living from the non-living. But I’d like to stand by the fact that buildings are almost humans!