(Fwd) Re: sets/ autopoise, self-.......

Bruce Edmonds (B.Edmonds@MMU.AC.UK)
Tue, 12 Sep 1995 08:43:24 GMT


forward to pcp

> Hans-Cees writes:
> >> - a self-reproducing system must be autopoietic
> >
> >I do not agree. How about Eigen's hypercycles? Although I am not an
> >expert on this, it seems that before there was autopoietic life,
> >there were some sort of reproducing systems that were not capable of
> >self-producing.
>
>
> I'm not familiar with Eigen's hypercycles. Could you describe them?

That's the trouble of using examples you are no expert in; people
will force you to become one :-(
But I will try.
Eigen's hypercycles are a theory that is used to describe how the
first life on earth has come to be. The story goes that a kind of RNA
existed that was able to copy itsselve extremely simply, and that had
some variation in copying. These are the things you need to start an
evolutionary process, and so the RNA could become more and more
sophisticated in self-copying. The kind of structures that emerged
are called hyper-cycles, or the process is, I am not sure :-(.
There are theories that state that the cell-surrounding has been an
adaption to yield more stable hyper-cycles, and that with this
adaption other mechanisms and processes became probable, that we know
now in cells. This is about how much I know.
Eigen has developed the idea of hyper-cycles extremely broad [a lot
of books,], and it seems that Ulanowits [or something like that] has
used his approach to look at ecosystems, also containing cycles of
energy, material, etc.
The point is however, that there were replicating molecules, that
have evolved self-producing features through time. If this theory is
right, there have been, or are possible, molecules that
self-reproduce, but that do not self-produce. Because they did not
have mechanisms yet to protect themselves from deterioration; it was
simply a matter of replicating faster then falling apart.

I invite those that know Eigen's theories better then I do to correct
me, but I think my point theoretically is clear.

references:
Eigen M (1979) The hypercycle; a priciple of natural
self-organization. Berlin, springer
(1987) Srepr towards life: a perspective on evolution, 1992 Oxpord UP
(1971) Self-organization of matter and the evolution of biological
macro-molecules Die natyrwissenschaften 58: 465-522

Theories come and go, the frog stays [F. Jacob]
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