Metabolism

Metabolism (pronounced muh-tab-uh-liz-uhm)

(1) In biology and physiology, the sum of the physical and chemical processes in an organism by which its material substance is produced, maintained, and destroyed, and by which energy is made available; the chemical processes that occur within a living organism in order to maintain life.

(2) Any basic process of organic functioning or operating; inorganic metaphors, applied to the processes that maintain any dynamic system) are sometimes technically dubious but widely used even in fields like theology, poetics, and entomology.

(3) A post-war movement in Japanese architecture and structural engineering which fused the concepts and design metaphors in architectural mega-structures with those of organic biological growth (always with initial capital).

1878: From the French métabolisme, the construct being the Ancient Greek μεταβολή (metabolḗ) (a change) from metaballein (to change) or from μεταβάλλω (metabállō) (I change, I alter) + -ism.  The construct of metaballein was meta- (change) + ballein (to throw), from the primitive Indo-European root gwele- (to throw, reach).  The –ism suffix is from the Ancient Greek ισμός (ismós) & -isma noun suffixes, often directly, sometimes through the Latin –ismus & ισμα (isma) (from where English picked up ize) and sometimes through the French –isme or the German –ismus, all ultimately from the Ancient Greek (where it tended more specifically to express a finished act or thing done).  It appeared in loanwords from Greek, where it was used to form abstract nouns of action, state, condition or doctrine from verbs and on this model, was used as a productive suffix in the formation of nouns denoting action or practice, state or condition, principles, doctrines, a usage or characteristic, devotion or adherence (criticism; barbarism; Darwinism; despotism; plagiarism; realism; witticism etc).

The verb metabolize dates from 1887 (transitive) (to subject to metabolism, transform by assimilation or decomposition) and 1934 (intransitive) (to perform metabolism) was from the Ancient Greek μεταβολή (metabolḗ) (a change).  The adjective metabolic was first noted in 1845 in the biological sense (exhibiting or affected by metabolism), from the German metabolisch (1839), from the Ancient Greek metabolikos (changeable) again from μεταβολή (metabolḗ).

The mammal with the slowest metabolism: The three toed sloth

Famously slow-moving, travelling typically at an average speed of 0.15 mph (0.24 km/h), three-toed sloths are tree-living mammals which inhabit South and Central America.  After seven years of studying three-toed sloths (and one can understand why it might take a while), scientists at the University of Wisconsin–Madison confirmed they are the mammals with the slowest metabolism on earth.  Essentially, a metabolism is sum of the physical & chemical processes by which cells produce the substances and energy needed to sustain life. As part of metabolism, organic compounds are broken down to provide heat and energy in the process called catabolism.  The overall speed at which an organism carries out its metabolic processes is termed its metabolic rate.

They also looked into what had long been repeated, even before the internet, but which turned out to be an urban myth: that the three-toed sloth defecates but once a month and the process takes three days.  It seems that was based on and observational study of one animal in captivity and that behavior was not typical of those in the wild.  In their natural habitat, the languid creatures defecate about once a week and take around an hour, a frequency explained by their peculiar diet; each meal taking about eight days fully to digest.  By comparison, sloth copulation lasts an average of twenty-five minutes which is not unimpressive but the authors of the study did note the act was done “not especially energetically”.