What is life? How Chemistry Becomes Biology Taking his title…

What is life? How Chemistry Becomes Biology

Taking his title from a pamphlet written in the 1930’s by the physicist Ernst Schrödinger (and well worth a read in itself), chemist Addy Pross has written this short book in order to summarise the current state of knowledge into life’s enduring mysteries while advancing his own hypothesis as to how it might have started to the already large pile of plausible chemical pathways that have been advanced in recent years. I feel that despite the Life Sciences going through a golden age with large advances being made over the last century this question remains far from answered, and that the distinction between life and not life remains to be distinctly outlined. Nor has anyone come up with a comprehensive account of what the difference is between a living organism and a corpse. It seems to me that the so called elimination of the ‘elan vital’ question by the biological sciences in the late 19th/early 20th century CE rests only upon the razor of William of Occam rather than any positive scientific evidence whatsoever, just on the fact that we can’t find it to label it. Parsimony will only get you so far in science, and I think this issue is one where it has held us back.

That said he does give the question an honest attempt at an answer after spending the first chapters outlining the problematic aspects of life that physicists don’t like for example the fact that life seems to contradict the second law of thermodynamics and the gradual dissipation of pattern and energy as time unfolds known a s entropy by harnessing and using energy in varied ways in order to keep these laws at bay and remain in a state of chemical and physical disequilibrium, at least for a time viewed from the perspective of an individual organism. He then outlines past attempts at answering the question from Darwin onwards, and discusses the reductionist versus holism debate (not to my satisfaction, but I enjoyed arguing with it as I read).

Then chemistry is introduced outlining how reactions happen and some of the complexity of biochemistry and posits a second kind of stability, one that spreads through time while changing as it goes along, resting on the analogy of never seeing the same river twice because the water molecules flowing down the bed are always changing being applicable to life’s particular kind of stability. Replicators (in the sense meant by Dawkins) are then discussed along with the basic outlines of the main hypotheses of what the initial ones to evolve might have been (eg the RNA world) and suggesting that the original ones may have vanished after being used as a framework by proto RNA which started as their information storage and metabolic tool during a chapter copnsecrated to the origin of life problem.

The next chapter discussed biology’s identity crisis and the fact that despite a century of tremendous advance exploring the trees of biochemistry and genetics, the perception of how a forest works as an ecosystem (to remain with his metaphor) remains dim. Then he finally outlines his solution coming from his own branch of science: systems chemistry. His plausible pathway to life is based (as some others are) on the concept of autocatalytic reactions that feed off themselves based on chemical kinetics and energy efficiency of reactions, which he equates with the beginnings of natural selection. He also equated evolutionary fitness with something he labels dynamic kinetic stability, the second kind of stability that he outlined, one where pattern manages to propagate itself through time, as individual, species or the great river of life itself. He then brings in the problem of teleology or life’s seeming purposive direction with maximising fitness, ie dynamic chemical stability. He concludes with a discussion with a discussion of the replicators first versus metabolism first to posit a coevolution of both from near the start of the process, but starting with replicators.

While the argument holds water, I’m not remotely convinced that it comes close to answering the questions. His last concluding section is the most interesting, showing how his theory applies to the varied problems he outlined at the start of the book and that 2 kinds of evolution exist, one applying to matter and one applying to life. He packs a great deal of data into a short work without seeming dense, and reading this alone would give a good if low on detail outline of the current state of play regarding these complex and still (to my mind at least) mysterious issues.

One thing none of the works on the topic I have read ever seem to discuss is viruses, they are the simplest form of DNA replication and are usually ignored because they can’t replicate in a non parasitic manner. It seems to me that their study might offer some interesting contribution, and am surprised that everyone writing on its goes on about archaean metabolic pathways and the RNA world without ever mentioning them.

Loz

Image credit: 1, E coli: Rocky Mountain Laboratories/NIH 2: Adam Dachis 3: cc on Pixabay 4&5 Pexels.com