Thursday, December 27, 2012

Abiogenesis: metabolism or information? Better question: chicken or egg?

Abiogenesis, the idea that life arose from inorganic matter, is between a rock and a hard place. If the origin of life began with metabolism, the first life molecules were so simple they could not copy themselves. If it began with information, the first life molecules had to be so complicated that they have never been produced by reasonable chemical processes. The real answer can be found in the age-old question: "Which came first, the chicken or the egg?"

(excerpts from Timothy R. Stout, Testimony of the Origins Divice, published in Creation Matters, a publication of Creation Research Society, Volume 17, Number 5, September/October 2012, to appear at http://www.creationresearch.org/creation_matters/pdf/2012/CM17%2005%20low%20res.pdf)

Melissa Lee Phillips published an article not too long ago in BioScience magazine titled, “The Origins Divide: Reconciling Views on How Life Began” (Phillips, 2010). In it she gives a history of the understanding of abiogenesis, the idea that life arose from inorganic matter.

Regarding the large macromolecules which are so critical to the functioning of living organisms, she commented,
All of these molecules and processes are so intertwined that it’s difficult to imagine how any of them could have arisen without the others already in place. Chicken-and-egg problems abound.
It turns out that the big, fundamental divide facing abiogenesis researchers today is whether the origin of life was information first or metabolism first. Study has revealed serious problems with both of these situations! The molecules which are proposed to have arisen in the metabolism-first scenario are simple enough to have achieved some level of concentration in plausible prebiotic chemical processes. However, the fact that these molecules do not copy themselves is a critical shortcoming since reproducibility is a fundamental, required characteristic of life.


Phillips says: "The metabolism-first model proposes that life probably arose at deep-sea hydrothermal vents, like the black smoker pictured here, when very simple molecules such as carbon dioxide, hydrogen, and hydrogen sulfide reacted with each other on the common iron-sulfur minerals pyrrhotite and pyrite. Photograph: OAR/National Undersea Research Program (NURP); NOAA."

By contrast, the molecules associated with an information-first scenario are so complicated that they have never been produced by chemical processes which can be reasonably associated with prebiotic circumstances. The meager positive results occasionally observed experimentally in- variably are found to have required extensive human intervention. Indeed, Phillips quoted Jim Cleaves of the Carnegie Institute for Science who said that whenever researchers manage to synthesize an interesting molecule, “it’s such a complex and kind of contrived experiment, it’s hard to really swallow.”


Phillips says: "The 'RNA world' model arose with the discovery of ribozymes—RNA molecules, such as the self-cleaving hammerhead ribozyme depicted here, that can act as catalysts. Could these self-replicating molecules have evolved from short, noncatalytic stretches of RNA, or would an autocatalytic network of chemical reactions have had to come first? The pink spheres are Mg11ions that stabilize the structure of the ribozyme. Graphic: Kalju Kahn and Esther Zhuang, University of California, Santa Barbara; created with PyMol (DeLano Scientific)."
Finally, after six pages of pointing out major problems at every level of abiogenesis, Phillips endeavored to end the article on an optimistic note by discussing the new “emergent systems” approach.

In this approach, scientists “toss dozens or hundreds of chemicals together and see what happens.”  John Sutherland of the University of Manchester, United Kingdom, declared, “We spent fourteen years exploring all that assembly chemistry and were largely extremely unsuccessful…” Then, using this “systems” approach, they discovered a method to make RNA nucleotides, the only successful effort by abiogenists to make nucleotides (Powner et al., 2009)

However, they did not just step back and watch the synthesis happen. In order to avoid a series of problems, not the least of which was the formation of tar, they had to monitor and control the process very carefully.  In another article, Benner and others simply chalk this up as another example of an experiment which is supposedly plausible for a prebiotic scenario, but which realistically requires far too much human intervention to be suit- able (Benner et al., 2012 )

Sixty years of study in abiogenesis has not provided the anticipated solutions to the problem of life’s origin, but just the opposite! The abundance of “chicken-and-egg problems” implies the necessity of all of these components making a simultaneous, first appearance, in a fully-functioning interdependent form. If there were no religious implications, the evidence would be sufficient to make the case and this would be the end of the discussion.

Of course, there are religious implications and this changes the entire character of the discussion.

The Bible states that the Creation of the entire cosmos (universe) took place in six days. It is clear from the context that these were literal days, not figurative. Experts have failed to build a scientifically-defensible case otherwise. 
 Illustration from the Creation Facts Screen Saver
Marko's comment: It seems that scientists always like to talk about “chicken-and-egg problems." Which came first, the chicken or the egg? Thinking people who also believe that there is a God who gave us the Bible - they know the answer. It's the chicken! Created on Day Five of the Creation week! How did life arise from inorganic matter? The answer is not in the primeval depths of time, it is that God Himself called living creatures into being.

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References

Benner S.A., H-J. Kim, and Z. Yang. 2012. Setting the stage: The history, chemistry, and geobiology behind RNA. Cold Spring Harb. Perspect. Biol. 4:a003541. doi: 10.1101/cshperspect.a003541

Phillips, M.L. 2010. The origins divide: Reconciling views on how life began. BioScience 60(9). 10.1525/bio.2010.60.9.3.  Retrieved October 25, 2012, from www.deepdyve.com/lp/university-of-california-press/the-origins-divide-reconciling-views-on-how-life-began-vOMlkgH3Lk

Powner, M.W., B. Gerland, and & J.D. Sutherland. 2009. Synthesis of activated pyrimidine ribonucleotides in prebiotically plausible conditions. Nature. 459:239–242. doi: 10.1038/nature08013

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