Between Necessity and Probability: Searching for the Definition and Origin of Life (Advances in Astrobiology and Biogeophysics)
This study investigates the major theories of the origins of life in the light of modern research with the aim of distinguishing between the necessary and the optional and between deterministic and random influences in the emergence of what we call ‘life.’ Life is treated as a cosmic phenomenon whose emergence and driving force should be viewed independently from its Earth-bound natural history. The author synthesizes all the fundamental life-related developments in a comprehensive scenario, and makes the argument that understanding life in its broadest context requires a material-independent perspective that identifies its essential fingerprints.
Univ. fo Southern California, Los Angeles. Investigates the origins of life in light of modern research. Presents the fundamental life-related developments, including the history of bioenergy, the origin of cell boundaries, the origin of early specificity, the origin of handedness, and more. For researchers.
An interesting book about a fundamental question, November 7, 2004
How did life originate? Well, it’s a wide open question. As Popa tells us, an explanation that is missing a critical step won’t do. There are plenty of clues. But Popa shows us that there are still many approaches to putting the clues together.
There are plenty of approaches that are being pursued today. Popa tells us about many of them. Still, let’s remind ourselves of some of them. One is to look for fossil evidence and DNA evidence of our earliest ancestors. Say that these turn out to be hyperthermophiles. Use that information, as well as the stability properties of RNA and DNA, to deduce the environment life originated in. A second idea is to look at the way we synthesize RNA (or DNA) today. Use that information to speculate about how the first RNA and DNA evolved. A third idea is to look at the self-assembly properties of entities for clues. A fourth idea is to note the similarity of ATP and the nucleic acid adenine. Assume this is no coincidence! A fifth idea is to do all sorts of experiments with collections of monomers and see if they arrange themselves into replicating strings. A sixth idea is to concentrate on computer simulations of all this. Computer simulations of the origin of replication show that there are some dangers, such as the "selfish RNA catastrophe," the "short-circuit catastrophe," the "population collapse catastrophe," and simply the risk of too many replication errors. Draw conclusions from the fact that these hazards were successfully avoided. A seventh idea is to at least answer the question of what came first, replication, metabolism, or cellularization. And so on. It seems that there is a great deal we aren’t at all sure of.
Popa starts with the issue of the issue of the development of cellularization, metabolism, and replication. He asserts that since all are needed for life, they must have evolved together, not serially. He states that the ATP coincidence probably is unimportant, with ATP’s use as an energy carrier being a late development. And he takes on the mathematical modelers by stating that they generally omit first order effects by not tracing the energy flow and the degradation of the evolving entities.
The issues Popa dwells on most are the energy sources, bioinformation, chirality, and the origin of specificity (as opposed to "metabolism" or "homeostasis"). Of these, the part on chirality was the most interesting to me. Popa discusses the implication that life’s chirality implies the existence of some large-scale chiral driver, such as rotating vortices or asymmetries in right and left circularly polarized light.
There’s also quite a bit of useful material about the definition of life. Popa is right to make the point that "life" and "living entities" are not at all synonymous.
Anyway, it is an interesting book about a tough problem: I’m glad I can just read about it and don’t have to solve it!