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This Concept Map, created with IHMC CmapTools, has information related to: n6. Catalysis and Development, When the probability of catalysis is high, the diversity of kinds of food molecules is sufficiently high, or both, the system is suspracritical and generates an explosion of new molecules that in turn catalyze others, etc. and the system has gone supra-critical. ???? When the probability of catalysis is low, or the diversity of the kinds of food molecules is low, or both, the generation of novel kinds of molecules soon dwindles to nothing. Behavior is sub-critical., This is called supra-critical behavior which has its source in the same kind of phase transition of catalyzed reactions to connected webs that may have pushed molecules into living organisms in the first place. ???? In supra-critcal chemical systems, molecular species beget other molecular species until the wondrous cloud coalesces into everything from trilobites to flamingoes., The sub-critical / supra-critical boundary must have always set an upper limit on the molecular diversity that can be housed within one cell. ???? Many small ecosystems exist. Hydrothermal vents, the bacteria in the human gut, etc. Those ecosystems are able to generate their own supra-critical explosions of molecular diversity., The diversity of organic molecules at the birth of our planet, and at the inception of life, was probably very low. Yet now, there are countless kinds of organic molecules. Somehow, in some mysterious way, the organic molecular diversity has taken energy from the sun, hydrothermal energy, or lightning bolts, and cooked itself up from simple molecules to the complex molecules we find today. ???? The striking possibility is that the biosphere causes is own explosion of organic molecules. The diversity feeds upon itself, driving itself forward., This is called supra-critical behavior which has its source in the same kind of phase transition of catalyzed reactions to connected webs that may have pushed molecules into living organisms in the first place. ???? Sufficiently diverse mixtures of chemicals reacting with one another can "catch fire”, achieve catalytic closure, and suddenly emerge as living, self-reproducing, evolving metabolisms., Since the community is supra-critical, a variety of novel molecules will be persistency formed, but, in turn, these will drive a succession of such extinction events. The extinction events, in turn, should tend to move the species diversity of the ecosystem from the supra-critical regime to the sub-critical regime. ???? There is a persistent immigration of new species from neighboring ecosystems which also may tend to increase the diversity of the species in the ecosystem, driving the system back from the sub-critical to the supra-critical regime., n6. Catalysis and Development ???? The diversity of organic molecules at the birth of our planet, and at the inception of life, was probably very low. Yet now, there are countless kinds of organic molecules. Somehow, in some mysterious way, the organic molecular diversity has taken energy from the sun, hydrothermal energy, or lightning bolts, and cooked itself up from simple molecules to the complex molecules we find today., Cells interacting with one another and with the environment create new kinds of molecules that beget other kinds of molecules. ???? This is called supra-critical behavior which has its source in the same kind of phase transition of catalyzed reactions to connected webs that may have pushed molecules into living organisms in the first place., Control of the supra-criticality can be accomplished by two mechanisms. Limiting the number of chemicals available, the “food" particles, and tuning the probability that any polymer can act as a catalyst for any of the possible ligation, or cleavage, reactions among the polymer substrates. ???? Chemicals can act as catalysts that act on other chemical substrates to create still further chemical products. Molecules can be both substrates and catalysts. Thus, the supracriticality already present at the emergence of life as collectively autocatalytic sets., Some transformations of novel molecules may be toxic to the cell, or otherwise result in its death. This extinction of cells, or species, will lower the diversity of species present in the ecosystem. ???? Since the community is supra-critical, a variety of novel molecules will be persistency formed, but, in turn, these will drive a succession of such extinction events. The extinction events, in turn, should tend to move the species diversity of the ecosystem from the supra-critical regime to the sub-critical regime., This is the source of the creative tension that brings about the ever-increasing diversity of the biosphere. This tension drives communities of cells to balance on a phase transition between the sub-critical and the supra-critical regimes which drives the creation of molecular novelty in the biosphere. ???? Control of the supra-criticality can be accomplished by two mechanisms. Limiting the number of chemicals available, the “food" particles, and tuning the probability that any polymer can act as a catalyst for any of the possible ligation, or cleavage, reactions among the polymer substrates., Two-substrate, two-product reactions are very common, and typically involve breaking one or more atoms off one molecule and bonding them onto the second. For any two reasonably complex organic molecules there is at least one legitimate two-substrate, two-product reaction that the two can undergo. Once the system is ignited, it will keep expanding exponentially in diversity. ???? Communities of cells evolve to the critical / sub- critical boundary., Communities of cells evolve to the critical / sub- critical boundary. ???? The sub-critical / supra-critical boundary must have always set an upper limit on the molecular diversity that can be housed within one cell., Eating and digestion are one mechanism to slow down the incorporation of new molecules, and may help maintain the cells at sub-criticality. ???? If the expected number of “progeny” of a “parent” chemical is greater than 1.0, the lineage is expected to increase in diversity indefinitely. If the expected number of progeny is less than 1.0, then the lineage is expected to die out., The twin pressures from the sub-critical regime toward the supra-critical and from the supra-critical to the sub-critical meet in the middle, at the boundary between sub- and supra-critical behaviors. ???? Local ecosystems evolve to the sub-critical / supra-critical boundary and then remain there, poised ever after by the pressure of sub-critical lethality, and supra-critical opportunity., The striking possibility is that the biosphere causes is own explosion of organic molecules. The diversity feeds upon itself, driving itself forward. ???? Cells interacting with one another and with the environment create new kinds of molecules that beget other kinds of molecules., While each ecosystem is itself on the boundary between sub- and supra-criticality, by trading stuff between them they collectively produce a supra-critical biosphere, one that inexorably becomes more complex. ???? Cells live in complex communities that always have traded and always will trade the molecules that each cell creates., The biosphere as a whole is supra-critical, like a mass of fissioning atomic nuclei, but the individual cells that make up the biosphere must be sub-critical; otherwise the internal molecular explosion of diversity would be lethal. ???? This is the source of the creative tension that brings about the ever-increasing diversity of the biosphere. This tension drives communities of cells to balance on a phase transition between the sub-critical and the supra-critical regimes which drives the creation of molecular novelty in the biosphere., Sufficiently diverse mixtures of chemicals reacting with one another can "catch fire”, achieve catalytic closure, and suddenly emerge as living, self-reproducing, evolving metabolisms. ???? The biosphere as a whole is supra-critical, like a mass of fissioning atomic nuclei, but the individual cells that make up the biosphere must be sub-critical; otherwise the internal molecular explosion of diversity would be lethal., That very creativity poses the most profound danger for the cells that create it, nest within it, are sustained by it, but must survive it. The solution is that the cells themselves are sub-critical. ???? Eating and digestion are one mechanism to slow down the incorporation of new molecules, and may help maintain the cells at sub-criticality.