|Life: systems that have at least the following characteristics are alive metabolism, energy input and output, reproductive capacity, adaptation to environmental changes while maintaining the system's own stability. See also systems, bodies._____________Annotation: The above characterizations of concepts are neither definitions nor exhausting presentations of problems related to them. Instead, they are intended to give a short introduction to the contributions below. – Lexicon of Arguments. |
Stuart Kauffman on Life - Dictionary of Arguments
Primordial Soup/Kauffman: Earth's atmosphere mainly hydrogen, methane and carbon dioxide.
Vs: it should have been extremely diluted.
Solution: new theory by Alexander Oparin, biophysicist, Soviet Union: When glycerine is mixed with other molecules, gel-like structures are formed which are called coacervates. Inside these structures, the molecular processes are isolated from the diluted aqueous environment.
Life/Emergence/Stanley Miller, 1952: received amino acids from the primordial soup tracted with lightning in the laboratory.
DNA: pure DNA does not replicate itself. This requires complex mixtures of protein enzymes.
Life/Development/RNA/Kauffman: a naked, replicating RNA molecule would be conceivable. It would be a more promising candidate for the first living molecule. Practically never succeeds in experiments. There are only balls instead of stretched structures.
DNA/RNA/Kauffman: 10 years ago (until 1985) it was believed that the two are largely inert chemical information stores. Then it was discovered that the RNA itself can act as enzymes! Ribozymes. They cut out their introns themselves.
Life/Emergence/Kauffman: Assuming that such a molecule had been created. Could it have defied mutation-related destruction?
Could it have gone through a development? Both times: probably no!
Problem: Error catastrophe.
2. KauffmannVs: it is unlikely because those bare RNA molecules are not complex enough.
All living beings have a certain minimum complexity which cannot be undercut!
The simplest living organisms, the bacteria "Pleuromona" already possess cell membranes, genes, RNA, particles for protein synthesis, proteins.
Question: why is a system simpler than Pleuromona not viable?
Life/Kauffman: Thesis: Life is not bound to the magical power of matrix replication, but is based on a deeper logic.
Life is an inherent characteristic of complex chemical systems. As soon as the number of different types of molecules in a chemical soup exceeds a certain threshold, an autocatalytic metabolism suddenly occurs in a self-sustaining network of reactions.
Life was already complex at the time of its creation and has remained so to this day.
The roots reach deeper down than to the level of the double helix, they are based on the laws of chemistry itself.
Life/Development/Kauffman: Assuming that the laws of chemistry would be somewhat different, e. g. nitrogen four instead of five valence electrons and therefore only four instead of five possible binding partners. Key: Catalysis.
Life: Condition of emergence: catalytic closure. This is necessary, but not yet sufficient. Chemistry/Reaction/Kauffman: in general, chemical reactions are reversible.
Life/Kauffman: thesis: the emergence of autocatalytic formations is almost inevitable.
In more complex systems, the number of edges compared to the nodes is increasing.
Molecules with the length L can be composed of smaller polymers in L-1 ways.
All we need is sufficient molecular diversity.
Life/Kauffman: Thesis: simple systems do not achieve catalytic closure. Life emerged in one piece and not in successive steps, and it has retained this holistic character to this day._____________Explanation of symbols: Roman numerals indicate the source, arabic numerals indicate the page number. The corresponding books are indicated on the right hand side. ((s)…): Comment by the sender of the contribution. Translations: Dictionary of Arguments The note [Author1]Vs[Author2] or [Author]Vs[term] is an addition from the Dictionary of Arguments. If a German edition is specified, the page numbers refer to this edition.
At Home in the Universe: The Search for the Laws of Self-Organization and Complexity New York 1995
At Home in the Universe, New York 1995
Der Öltropfen im Wasser. Chaos, Komplexität, Selbstorganisation in Natur und Gesellschaft München 1998