Adaptation
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<i>Adaptation</i>
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The history of structural change without loss of identity in an autopoietic unity is its
ontogeny. The coupling of the changing structure of a structurally plastic autopoietic
unity to the changing structure of the medium is called ontogenic adaptation. The history
of successively produced, historically connected unities generated through sequential
reproductive steps is evolution. The coupling of the changing structures of the
sequentially generated unities to a changing medium is called evolutionary adaptation.
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Ontogenic and evolutionary adaptations in living systems arise through the selection of
the structures that permit the autopoiesis of the living system in the medium in which it
exists. In both cases, selection takes place as a differential structural realization that
results from the operational confrontation of systems endowed with independently
determined domains of structural diversity and plasticity. In the case of the evolution
all the structural diversity of living systems, available for selection is produced in
them in parallel, through each reproductive step, as a result of their genetic properties,
and the selection takes place as differential survival or differential reproductive
success. In the case of ontogenic changes, the structural diversity of living systems
available for selection is present, at any instant, in the domain of perturbations of each
living system, and selection takes place during the history of each individual according
to the sequence of perturbations provided by the medium. No example of evolutionary
selection is needed. As examples of ontogenic selection the following two are presently
adequate:
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In vertebrates, specific immunity responses result from the differential multiplication of
cells capable of producing antibodies when the organism is confronted with antigens that
select, through differential triggering, which cells multiply (Edelman, 1975).
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The consolidation of bone lamelli following the lines of stress is a result of the
preferential reabsorption of lamelli that are not under stress from a domain of lamelli
otherwise in continuous turnover and initially deposited with no preferential relation to
stress (J. Y. Lettvin, personal communication, 1976).
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Adaptation, then, is always a trivial expression of the structural coupling of a
structurally plastic system to a medium. Adaptation always results from sequences of
interactions of a plastic system in its medium that trigger in the plastic system
structural changes or changes of state that, at any instant, select in it a structure that
either matches (is homomorphic to) the structure of the medium in which it operates
(interacts or behaves) as such a system, or disintegrate it. It follows that, in the
operation of living systems as autopoietic unities in a medium, the coincidence between a
given structure of the medium (place in the medium) and a given structure in the living
system is always the result of the history of their mutual interactions, while both
operate as independent, structurally determined systems. Furthermore, as a result of the
structural coupling that takes place during such a history, history becomes embodied both
in the structure of the living system and in the structure of the medium, even though both
systems necessarily, as structure-determined systems, always operate in the present
through locally determined processes. Therefore, although from the cognitive point of view
adequate behavior as a case of adaptation cannot be understood without reference to
history and context, from the operational point of view adequate behavior is only an
expression of a structural matching in the present between organism and medium, in which
history does not participate as an operative component. History is necessary to explain
how a given system or phenomenon came to be, but it does not participate in the
explanation of the operation of the system or phenomenon in the present.
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