David Deamer: Five Decades of Research on the Question of How Life Can Begin (original) (raw)
Related papers
How Did Life Begin? Part I: Approaching The Problem
The American Atheist, 1989
In order to understand how llfe began on a lifeless earth, it is necessary to understand what life is. Life is defined in terms of a chemical cycle connecting DNA, RNA, proteins, and small molecules. The first cells were smaller and simpler than any living form of life, and the simplest life form know, the Pleuropneumonia-Like Organism (PPLO) is taken as a model for which to account in origin-of-life experiments. The role of religious ideation as a barrier to materialistic efforts to understand the origin of life is discussed. Part II: "Stardust in the Primordial Soup" and Part III: "The First Cells" will follow shortly.
Origins of Life: Questions and Debates
Oxford Encyclopedia of Planetary Science, 2017
This is an advance summary of a forthcoming article in the Oxford Encyclopedia of Planetary Science. Please check back later for the full article.Stanley Miller demonstrated, in 1953, that it was possible to form amino acids from methane, thus generating the ambitious hope that chemists would be able to shed light on the origins of life by recreating a simple life form in a test tube. However, it must be acknowledged that the dream has not yet been accomplished, despite the great volume of effort and innovation made by the scientific community.At minimum, primitive life can be defined as an open chemical system, fed with matter and energy, capable of self-reproduction—that is, making more of itself by itself—and also capable of evolving. The concept of evolution implies that the chemical system transfers its information fairly faithfully, but makes a few random errors. By chance, some parts of the self-assembly are then capable of generating a copy. Sometimes, a minor error in the p...
Contemporary theories of the origin of life divide along the same conceptual lines as contemporary accounts of the nature of life, with small molecule theories (e.g., Wächtershäuser's iron pyrite world) corresponding to metabolic theories/definitions of life and genes-first theories (currently dominated by the RNA world) corresponding to evolutionary (e.g., chemical Darwinian) theo-ries/definitions of life. I discuss some difficulties faced by this general approach: First, it isn't at all obvious that a successful theory of the origin of life will divide along the same lines as a theory of the nature of life. Second, in both cases there is the worry that signs of life are being mistakenly treated as essential to life. Third, most theories of the origin of life tend to minimize or even side step the transition from nonliving ensembles of molecules to the first proto-organisms. I close with a suggestion for dealing with some of these difficult problems.
The Origin of Life and its Methodological Challenge
The problem of the origin of life is discussed from a methodological point of view as an encounter between the teleological thinking of the historian and the mechanistic thinking of the chemist; and as the Kantian task of replacing teleology by mechanism. It is shown how the Popperian situational logic of historic understanding and the Popperian principle of explanatory power of scientific theories, when jointly applied to biochemistry, lead to a methodology of biochemical retrodiction, whereby common precursor functions are constructed for disparate successor functions. This methodology is exemplified by central tenets of the theory of the chemo-autotrophic origin of life: the proposal of a surface metabolism with a two-dimensional order; the basic polarity of life with negatively charged constituents on positively charged mineral surfaces; the surface-metabolic origin of phosphorylated sugar metabolism and nucleic acids; the origin of membrane lipids and of chemi-osmosis on pyrite surfaces; and the principles of the origin of the genetic machinery. The theory presents the early evolution of life as a process that begins with chemical necessity and winds up in genetic chance. 7 1997 Academic Press Limited