Biology Reference
In-Depth Information
order they store by direct replication. This way the renewal of the increasingly
complex structure of certain components does not depend any more only on
the maintenance of an increasingly complex and holistic process, but on the
template-directed replication (which relies in a specific sequential order of their
building blocks). The robustness of the system may also significantly increase
because of the possibility to reliably produce new highly functional components
(despite their increased structural complexity). The so-far distributed dissipative
organization becomes this way preserved by means of a local conservative order
stored in modular template-like components. In other words, the maintenance
and reproduction of the organization becomes instructed.
Interestingly, the introduction of modular templates specifying the most
complex part of the functional organization of the system conveys an important
change: the formerly highly distributed and holistic organization opens the way
to a much more modular organization. This is an advantage, as in a modular
system the organization as a whole is less likely to be disrupted by a localized
failure. Thus, seen in an evolutionary perspective, modularity increases flexi-
bility and minimizes cascading malfunctions (Harold, 2001, p. 212). In total,
the introduction of this mechanism of unlimited memory changes so deeply the
organization and capacities of the primitive autonomous systems that it seems
convenient to give them a specific name. We have elsewhere (Ruiz-Mirazo et al.,
2004) used the term of hereditary autonomous systems (HAS).
Let us go now to the more fundamental question. Given that modular tem-
plates now control both the maintenance and reproduction of the system, all
random changes in these components (allowing viable reproduction) will lead to
a process of exploration of the sequential space linked to a correlative selective
retention of the more efficient organizational forms.
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This allows the recruit-
ment by the individual autonomous systems of the results (end-products: selected
patterns) of a slow process of natural selection, which is much more encom-
passing as it takes place beyond these individual autonomous systems. Thus
the evolutionary process in which the whole population and its environment
are involved largely determines the changes that take place at the level of the
sequences of the templates. These templates become a kind of material memory,
which can reliably transfer organizational changes from one system to another.
In this way, the systems endowed with modular templates can combine coher-
ently and consistently the individual dimension of their activity (related to the
self-construction/self-maintenance of each of them) with a progressively more
important temporal and spatial dimension (related to their long-term maintenance
and evolution as a whole population). But the most important consequence is
the increase in the complexity of the metabolic organization that this insertion
in a historical and collective dimension allows.
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Provided there exist certain additional constraints, like competition for resources in a limited space.
