Control Structure

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Governance Interface with Organization Units
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Living system homeostatic control involves orchestrated interaction between a living system's governance mechanism, its organization units and components. In the diagram below, the red box represents a living system's governance mechanism, and the blue box represents the rest of that living system, including its organizations, its component living systems, and their lower-level structures.

The diagram in the red box shows the governance view of control. It includes a portion of the Scenario Control Unit diagram, which is extended here to show how governance interfaces with the rest of its living system. It portrays how governance sees only its initiation of the control command, and how it must wait for sensory feedback to determine the results of that command.

The diagram in the blue box shows the living system view of what happens after the control command is received from governance. It portrays the three phases that are required to respond to that control, each of which involves the living system's organization units, their component living systems, and their lower-level structures down to the biomolecule level.

Governance Commands
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The governance mechanism issues control commands when physical action is needed to restore the homeostatic balance of the living system. This need occurs whenever one (or more) of the living system's life functions is not performing adequately, or when interactions (or anticipated interactions) with its environment require action.
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When one of these control commands has been issued, a three-phase process is required to provide a response that is recognizable by the governance control mechanism. That high-level mechanism cannot directly see the detailed physical action that takes place. It can only interpret resulting sensory patterns that indicate changes in the living system's external environment or internal conditions that may or may not satisfy the original need.

Control Structure Chart
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The following chart defines the overall control structure that is involved in the living system's response to a governance control command.
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Control Structure
Hierarchy Level	Control Initiation	Resulting Action	Sensory Awareness
Superorganism organization Organism organ Cell organelle Biomolecule

Hierarchy Level shows the entire sequence of control and response levels, from superorganism to molecule. Note that both living systems and their organization units are involved as separate control levels. When a control command is issued by a superorganism's governance mechanism, all levels shown below superorganism must participate.
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Control Initiation shows the three steps that occur within each level of living system and organization unit, as control proceeds from superorganism through the hierarchy to the bottom biomolecule level. Between any two levels of the hierarchy there is a fan-out, where a single higher-level control initiation has been orchestrated into multiple control initiations that are assigned to designated units at the next lower level.
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Resulting Action shows the three steps that occur within each living system and organization unit, as resulting action starts at the bottom biomolecule level and proceeds upwards to the superorganism level. Between any two levels of the hierarchy there is a fan-in, where collective results of the lower-level are combined to produce a new higher-level result.
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Sensory Awareness shows the three steps that occur within each living system and organization unit, as sensory awareness proceeds from bottom to top. At each level of the hierarchy there is a fan-in, where lower-level sensory inputs are integrated into a higher-level sensory pattern.

Specialization
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Specialization plays a key part in governance control. Throughout the control structure hierarchy, a myriad of different kinds of work is required. At all three living system levels, organization units and their components have been specifically designed and developed with capability to perform the prescribed kinds of work that are needed. Each control command results in an enormously complex sequence of highly-organized, controlled and specialized actions, starting at the biomolecular level and working up the hierarchy. The Living Systems Model embodies an abstraction of key features from this complexity, to provide an accurate but concise view of a living system's architectural structure.

Control Initiation Sequence explains how control is initiated step-by-step down through the entire hierarchy of control levels.