Genesis: The Scientific Quest for Life’s Origin, by Robert M Hazen. Joseph Henry Press, Washington, DC, USA. Reviewed by Bernard Howard.
There’s one thing I hope for before I die; to hear of some convincing facts, rather than speculation, bearing on the origin of life on Earth (I’m 86, so hurry up, chaps!). If one wanted a non-biblical, one word title for this book, it would have to be ‘Emergence’. The author writes: “The science of emergence seeks to understand complex systems-systems that display novel collective behaviours that arise from the interaction of many simpler components.” The development of life from non-life can, using this concept, be seen as a hierarchy of emergent steps, and these steps form a framework for Hazen’s survey of the field.
The initial emergence was of the simple molecules, the “building blocks” of living organisms, in the prebiotic world. The sugars, amino acids, etc, of which all living things on Earth are constituted, are the next necessary emergent step; the formation of these in the laboratory has been tried by various means, with varying success.
The next question is how these monomers could be combined under prebiotic conditions into the polymers-the proteins, nucleic acids, etc, without which complex life is impossible. The culminating emergent steps, the formation of membrane-bounded cells, and their coalescence into the first multicellular organisms, are just as mysterious.
A great variety of hypotheses have been proposed and ingenious experiments carried out, regarding all these steps, and Hazen, as far as I can judge, discusses them all. Early ideas appear to have originated mainly in Europe, starting with Darwin’s “warm little pond”, and the later speculations of Oparin, Haldane, Cairns-Smith, Prigogine, and Eigen and Wächtershäuser. The experimental work, as appears from this book, has been done wholly in the US, mainly by the author’s colleagues and buddies with occasional help from himself. Some readers will find the personal comments about these people and what they did lighten the tone of what can be fairly heavy going; others may find this a slight irritant.
Hazen’s wide-ranging survey should be comprehensible to those with high-school level biology and chemistry. Don’t look here for any answers, just an impartial laying out of competing explanations of only some of the steps leading to us and our fellow occupants of the planet. The mysteries remain, and the search continues.