Subsystems and Functions

A living entity is a unified system whose functionality is divided into key subsystems. These subsystems perform the life functions that are required for the entity's survival within its particular world environment. Two views are used to show how the conceptual subsystem functions are manifested within the living system's physical internal structure.


Two Views Are Needed
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The previous page presented an architectural structure that defines three levels of living systems, each of which is made up of subsystems. Within that framework, details of the subsystem functions will now be delineated in terms of an individual living system's internal structure. For this purpose, a shift in perspective is needed where two views are maintained side-by-side.
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Of the four analysis techniques previously presented, Systems Theory portrays the living system and its subsystems from an external perspective that ignores internal structure details. The other three techniques (Aggregate Object Concept, Organizational Theory, and Governance Control) provide the basis for an internal structural perspective that employs an aggregate object concept to portray the relationships of governance, organization units and components.
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External System View Internal Structure View
System
Governance
Subsystem Functions
Organization Units


Components

External System View
The breakdown of a system into subsystems is more conceptual than physical, because it relates to the overall system's emergent properties once it has been designed and constructed. For example, an airplane's system requirements may be described in terms of lift, thrust, steering, landing, passenger accommodating, etc. These functional specifications may be thought of as the design requirements to meet the purpose of the system.
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Internal Structure View
The breakdown of a system's internal physical structure relates to its physical parts and the actions they can take. Using the airplane example, these would be body, wings, engine, rudder, landing gear, etc. These physical "organs" have been physically designed and constructed to fulfill the conceptual functional requirements of the system. The set of physical organs does not necessarily match the set of functional requirements one-to-one, as long as all requirements are fulfilled.
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Some Definitions
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A living system is made up of a set of functional subsystems, a governance mechanism, various organization units, and an array of components.
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Subsystems define the life functions that must be performed to sustain the living system's internal health and existence in its changing environment.
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Governance is a special kind of control subsystem that monitors the living system's situation, in terms of both in it's external environment and its internal conditions, initiating functional action by the organization units as-needed for survival and to maintain internal homeostasis.
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Organization Units interpret governance directions and translate them into the specialized component actions that are required to fulfill them.
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Components perform the actual specialized work, as prescribed by their roles and current assignments within the organization units. Superorganism components are organisms, organism components are cells, and cell components are biomolecules.
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Governance has no direct contact with the components. Instead, governance control initiatives and directions are played out across the organization units which, in turn, translate them into specific physical work assignments for the components to perform.
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Subsystem Life Functions
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It is relatively easy to give examples of life functions for a particular level and kind of living system. For example, in an organism, its organs ingest and process food, distribute the results where needed throughout the body, gather and extrude of waste material, etc. Using the three-level architectural schema, the life functions have been categorized and compared across all three levels of living system. The conclusion reached here is that eukaryotic-based living organisms all have the same inherent structure, and based on their evolution from the same original cell:
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 Every Living System Must Have the Same Basic Architectural Structure 
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Building on this concept, the list of standardized subsystem functions shown in following table has been adapted from the original work on living systems by James Grier Miller. Although subject to further refinement, it is presented here to illustrate what a comprehensive list of the functionality necessary for life must look like. For each subsystem function, three examples of participating organization units are shown, one each from the cell, organism, and superorganism levels of living system. Note that
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Living System
Subsystem Life Functions
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Subsystem
Life Function
Purpose Participating Organization Unit Examples (three levels)
 Awareness: Maintain sensory awareness of external and internal conditions. membrane, eye, reporting system
 Perimeter: Maintain a barrier to protect from external environment. membrane, skin, border patrol
 Structure: Maintain proper relationships among organization units. cytoskeleton, skeleton, infrastructure
 Ingestion: Bring in material and energy from environment. membrane vesicle, mouth, farm
 Storage: Store material and energy within system for later use. vacuole, skin layer, warehouse
 Conversion: Transform ingested material into useful form. chloroplast, stomach, refinery
 Production: Construct needed materials within system. ribosome, bone marrow, manufacturing company
 Distribution: Transport material and energy within system. endoplasmic reticulum, artery, shipping company
 Extrusion: Send out material from within system. membrane vesicle, anus, sewer system
 Movement: Change location of system and/or move its parts. flagellum, legs, transporter
 Defense: Protect organization units and components from harm. membrane bacterial toxins, immune system, army
 Enforcement: Police rogue organization units and components who fail to follow rules of behavior. lysosome, lymph node, police department
 Repair: Fix structural damage or malfunction. lysosome, organ's healing mechanism, disaster recovery team
 Reproduction: Create similar offspring. chromosomes, genitalia, colonization team

Each subsystem shown it this table defines a living system function that must be performed as needed by the work of specialized component entities. This work is orchestrated by organization units that harness and focus the capabilities of component living systems. This applies to all three levels of living system.
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For example, a human organism is made up of cells that are organized within organs. Each organ is an intermediate structure that marshals the work of its member cells to perform part or all of one or more organism-level functions. Similarly, a cell is made up of biomolecules that are organized within organelles, and a superorganism is made up or organisms that are organized within organizations (non-profit and businesses).

Note 1: For brevity, an example of only one participating organization unit is shown for each level of living system. Numerous additional examples are readily available.
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Note 2: As indicated in the table, there is seldom a one-to-one correspondence between subsystem function and organization unit, because coordinated actions by multiple kinds of organization unit are often needed to produce a particular subsystem function.
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Note 3: The list of subsystem life functions shown here includes "Reproduction." This is based on the view that action toward reproduction is initiated because of a living system's inherent propensity, and that need is manifested as a homeostatic imbalance.
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Note 4: Organization units (organizations, organs, organelles) are intermediate structures, and are not living systems themselves. When life is perpetuated across generations, the thing being sustained is a set of self-replicating instructions for creation of the entire living system, not the independently for the internal organization unit structures that it produces. To perpetuate their species existence, superorganisms, organisms, and cells reproduce themselves. Organization units do not reproduce themselves.


Roles and Constraints looks beyond life functions to examine what living systems do, and why they do it.


©1995-2012 Ackley Associates    Last revised: 7/16/11
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