Huffington blog July 11, 2017
DARE TO BE 100
SYMMORPHOSIS
Symmorphosis is really an ugly word, but one that is much more important than its lack of recognition appreciates.
I first learned of it twenty years ago when I entertained Jared Diamond of UCLA to give a lecture to my group at Stanford about his Pulitzer winning, recent book Guns, Germs, and Steel. It has always been my habit when hosting a distinguished guest to look up what they have been up to recently, and I found that Jared had written a paper about symmorphosis, a word that I had never encountered before. I looked it up and it was a Eureka moment for me because I recognized its tremendous importance to things in which I am very interested, mostly dealing with aging.
Symmorphosis has to do with the economy of biologic design. It represents the adaptation of structure to function, one of my principal preoccupations. It is a catalog of how we become what we do. The scientific term for this process is phenotypic plasticity.
The term symmorphosis was coined by Weibel of Berne and Richard Taylor of Harvard. The concept was anticipated by D’Arcy Thompson who in 1917 wrote the book “On Growth and Form”. It was way ahead of it time. It is celebrated today as a classic. In its 793 pages it provides voluminous examples of the myriad ways that Mother Nature has crafted her progeny in the fashion that environmental challenge has required. The host of “Just So Stories” features the giraffe’s long neck as exhibit number one. The importance of Time in allotting sufficient interval for parenthood of the living world to operate was the subject of Richard Dawkins book, “Climbing Mount Improbable”. He traces the many evolutionary pathways that eventuate in the attenuated creation of the human eye, a miracle of symmorphosis. Several other types of photorecepters are referenced in other species.
It is noteworthy that oxygen delivery is the most common example used by proposers of symmorphosis to validate their thesis. Of all the many functions served by the body its capacity to move oxygen from the atmosphere to our fuel combusting machinery is its most critical. We can live a lifetime without thought (too many of us), we can live many decades without sex,(perish the thought),we can live months without food, we can live days without water, BUT we can live without oxygen for only four minutes. Hence its most critical rating.
The body has a multistep oxygen delivery system starting with the heart and lungs, but also requiring the delivery tubes, the trachea, the bronchi, the bronchioles, the arteries, veins, the capillaries, then the cellular membranes, and finally the mitochondria, the intracellular batteries that generate our fuel as ATP.
The principle of symmorphosis dictates that each of the individual components of the delivery system is quantitatively linked with all the others. Lacking this coordination would lead to a rate limiting step that would indicate disease. The whole is much more than the sum of its parts.
Maybe Aristotle knew about symmorphosis a long while ago.