Mathematical Biology, metabolism, origins of life, evolution

Discussion of everything related to the Theory of Evolution.

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Mathematical Biology, metabolism, origins of life, evolution

Post by GregorioKelly » Wed Oct 17, 2007 2:19 am

Origins of life theorists dispute whether metabolism or replication came first. Robert Shapiro argues the former, Addy Pross the latter. Shapiro enumerates 5 requirements for metabolism to have made possible replicators and evolution in the RNA world. Pross insists that metabolism and replication appeared simultaneously is untestable, and trivial for understanding life's processes. For Pross metabolism suggests pathways dependent upon specificable chemical reactions.

Harvard's Department of Organismic and Evolutionary Biology (DOEB) houses the Program of Evolutionary Dynamics (PED). The PED seeks to understand Darwinian evolution in terms of equations. All these equations are restricted to the RNA world. Martin Nowak, head of the PED, published the book Evolutionary Dynamics last year. The book did not have a single equation dealing with metabolism.

Lloyd Demetrius, a mathematical biologists at Harvard in the DOEB, has published a version of Kleiber's Law that includes the term for metabolic efficiency (ME). The equation deals with metabolic rate and biomass. The term ME occurs in the exponent of biomass, and is clearly a statement of efficiency of redox coupling. This means electrochemistry. Metabolic rate is then expressed in watts, and is a statement of the needed recharge rate of an electrolytic biomass for it to achieve equilibrium, to maintain itself and its organization.

The Demetrius version of Kleiber contrasts with the version trumpeted by the quarter-power scalers, many of whom are also from Harvard's DOEB , but a number of whom hail from the Santa Fe Institute. In this version the exponent is a straight 3/4, which only occurs when ME is 100%. This never happens, and effectively removes this treatment of the equation from any biological relevance. Yet this unsophisticated version is claimed to be the unifying metabolic theory of life that models the very efficiency that it assumes. This assumed efficiency of 100% is attributed to the fractality of capillarity, which occurs nowhere in the equation, and which removes the equation from consideration of things the size of bacteria or any single-celled animal.

In stark contrast to the limitations imposed on the relevance of the 3/4 exponent by its foremost proponents, they simultaneously hold that the metabolic rate of an organism is nothing more than the product of its average cellular metabolic rate and the number of its cells, as if capillarity had nothing to do with it either. This version of the equation is completely incapable of gaging the affects of biological organization of cells, let alone of the single cell, or the organic chemistry that resulted in cellular life. It is no wonder then that the secrets of longevity its proponents hint is there, are entirely impenetrable to them; that the fact that birds and rats of the same mass have life spans an order of magnitude different, is considered just as much an exception to the rule as is the longevity of primates compared to far more massive mammals.

The Demetrius version of Kleiber, on the other hand, models the nature of biological organization from organic chemistry to multicellular life; meets the five requirements enumerated by Shapiro for metabolism; treats metabolism and replication as inseparable on the basis of energy considerations alone and without being specific about chemistry; suggests that the origins and evolution of life are primarily about metabolism and only secondarily about genetics; models the relation between food availability and reproduction for things large and small; accounts for mutation, cancerous or otherwise, in terms of pressure on ME from energy scarcity; explains the nature of aging in terms of antagonism between basal and field or organism metabolic rate; explains why caloric restriction works on mice but won't work on humans; and justifies the discharge of the anode of a battery into the body at the neuromuscular junctions, to increase muscle cell mass and to increase longevity in humans the way caloric restriction does it in mice.

Anyone wishing to know more about this wonderful equation is encouraged to read the paper "The Terrestrial Evolution of Metabolism and Life - By the Numbers," which is accompanied by a set of graphs and a table of numbers. The highlighted numbers in the table appear on the graph. The mathematical analysis is presented in such a way as to lend itself, through deductive inference, to verifiable experiments the individual can perform upon self. If the moderator for this site does not make this paper and graphs and table available as an attachment, they will be available, upon request, from its author.

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