Biology Reference
In-Depth Information
not exist without organisms (or something almost likewise complex) how to
explain the appearance of organisms by evolutionary mechanisms?
The solution to this dilemma leads us to the question of the origins. If evolution
requires a certain threshold of organizational complexity, we have to search
what kind of principles would explain the appearance of such organization.
Which kind of properties/features that could have appeared in a purely physico-
chemical scenario (and that, despite such initial simplicity, could be capable
of generating a sequence of steps of increasing complexity) should the early -
necessarily simple - prebiotic organizations possess? How can such an intricately
holistic and complex organization appear from the much more 'simple' and
understandable physico-chemical world?
As has been mentioned at the beginning, the understanding of biological
organization will require many different principles. I am convinced that, unless
we understand how all these organizational principles have become entangled
together, we will not achieve a full understanding of life.
2. THE ORGANIZATIONAL PERSPECTIVE
The process by which living organization originated may probably be a sequence
of different forms of organization, progressing from relative simple to more
complex stages. In a general sense, the term organization means the activity
(or result) of distributing or disposing a set of elements properly or methodically.
Namely, in an organization there is a nonrandom arrangement of parts, generally
serving a purpose or function. However, for obvious reasons, in our case, we
have to discard any form of external design and/or purpose. That is why, in a
prebiotic context, the idea of organization is rather associated with the formation
of dynamical systems in which the random interaction of their parts generates
the 'emergence' of a global order.
The spontaneous emergence of order could take two different forms: self-
assembly (SA) and self-organization (SO). Unlike evolution, both SA and SO
are widespread phenomena, which do not require very complex elements or
systems. Self-assembly is a process in which a set of (randomly distributed)
elements group together, forming a stable structure (an order), e.g., a crystal.
This process is due to the material properties of the elements, namely, to the
forces acting among them. Thermodynamically, self-assembly can be described
as a process towards equilibrium, ending in a stable structure.
In both SA and SO there is the emergence of order from a set of randomly
interrelated elements. However, in the case of SO this order is not a conse-
quence of the structure of the constitutive elements,
2
but of certain boundary
2
However, as we shall see, complex forms of SO will require the introduction of a variety of specific
constraints in the constitutive elements.
