Biology Reference
In-Depth Information
Then, how can an NTSMS reinforce its own self-maintenance? This question
is strongly related with the problem of the increase in the complexity. Let us
see why.
In a scenario populated by primitive SM chemical systems the appearance
of new systems based on new components is very likely, therefore allowing
different forms of SM. Some of these new forms of SM may be simpler, but
others will probably create larger and more diverse networks. The interesting
point is that, within this variety of systems, some of them can generate new,
more efficient ways to achieve SM - for instance, increasing both internal
diversity and stability. In other words, a more complex organization may be
reached and preserved if it increases the capacity of self-maintenance of the
whole system. This fact is important because, in general, as the complexity of a
FFE organization increases, its maintenance becomes harder.
These considerations point to a key question. We have seen that the condi-
tion to preserve the new complexity generated is that it is functional for the
maintenance of the system. This can take place if the system becomes less
dependent on (the presence of) certain external conditions and, consequently,
more dependent on itself. Thus, the possibility of any significant increase in
complexity of the primitive SM chemical organizations implies a progressive
takeover of the external conditions necessary for their viability; and the only way
for this to happen is that the system recruits its own organization for the active
reconstruction of the necessary conditions of its maintenance. In other words, by
increasing their degree of autonomy with respect to the earlier minimal case. By
this, I mean a progressive takeover by the NTSM systems of the environmental
conditions necessary for their viability. Accordingly, a system can be considered
autonomous if its maintenance is more the consequence of its own organization
than of the structure of its external environment.
A crucial step in the evolution towards autonomy was the appearance of
systems whose organization includes the construction of a selective and func-
tionally active membrane.
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Such organizational change allows the components
of the system to be produced in much more favorable and stable conditions
(regulation of concentrations, selection of kinds of components, etc.). In this
way the generation and stability of more complex systems becomes possible.
Now the (internal) organization will appear much more integrated and complex
in respect to its environment than either the primitive autocatalytic networks
without physical border or the primitive micelles or vesicles.
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15
The incorporation of a membrane is a process that transcends the chemical frame, as it implies the recruitment
of certain independent processes of self-assembly.
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It is likely that cellularity integrated with the inner organization was preceded by more primitive cellular
systems (like micelles or vesicles enclosing independent SM organizations).
