Consider the humble thermostat. It regulates the temperature of your house through the simple device of a metal coil that contracts and expands with temperature, making and breaking an electrical connection to your furnace. You would not die without your thermostat, but your life would be less convenient and comfortable.
Your body also had a thermostat that regulates your temperature, along with other devices that regulate your heart rate, breathing rate, and countless other metabolic processes. If these regulatory mechanisms went awry, you would be severely compromised and in many cases you would die.
One of the pleasures of being a biologist is to learn about the regulatory mechanisms of the body in detail. A book titled The Flexible Phenotype: A Body-centered Integration of Ecology, Physiology, and Behaviour by Theunis Piersma and Jan A. van Gils, makes good geek summer reading. Here's a passage from their book describing the regulatory processes that take place when a snake eats a meal (84-85; see the book for supporting references).
"Pythons, boas, rattlesnakes and vipers are snakes that employ sit-and-wait foraging strategies. This makes them go without meals for so long that their stomachs, intestines, and accessory organs shrink and become 'dormant.' When these snakes do catch the occasional prey, it can be almost as big as themselves. Prey capture, killing by constriction, and swallowing through the extended gape elicits a burst of physiological activity, with drastic up-regulation of many metabolic processes. Immediately, the heart starts to grow. With a doubling of the rate of heartbeat, as blood is shunted away from the muscles to the gut, blood flow to the gut increases by an order of magnitude. Within two days, the wet mass of the intestine more than doubles. ... This is followed by 100% increases of liver and pancreas mass, and a 70% increase in kidney mass. At the same time, stomach acidity increases, ensuring that the skeleton of the ingested prey disappears within about six days. Many amazing changes, at several different levels of physiological action, takes place in the intestine, including the instantaneous lengthening of the microvilli."
You don't need to understand the details to appreciate the symphony of regulatory processes that takes place when a snake eats a meal. A similar symphony can be described for every species, including Homo sapiens. Two points can be made about the regulatory symphony that are highly relevant to the main theme of this series -- the concept of regulation in politics and economics.
First, the symphony is played spontaneously without any conductor. The snake doesn't have to think about how to digest its meal. If you want surefire examples of the invisible hand -- whole systems that work well without the parts having the welfare of the system in mind -- then look to the regulatory processes of individual organisms.
Second, the symphony was composed by natural selection. The regulatory systems that work for any given species are a tiny fraction of regulatory systems that don't work. And the regulatory systems that work for one species don't necessarily work for other species. Even different snake species have different regulatory systems, if you look closely enough.
One implication is that if you place a species in an unusual environment, its regulatory system can go spectacularly wrong. A fascinating example described in The Flexible Phenotype involves the response of our bodies to weightlessness in space (p 81-3).
"Astronauts and cosmonauts quite unwillingly lose body parts during their time in space. Remember the sight of weakened astronauts returning from Apollo missions on the TV screen? Without gravity a human environment is less demanding in several different ways and this shows up upon return to earth. One of the first things to be affected is the heart, which may shrink by as much as a quarter after one week in orbit. Heart atrophy is correlated with decreases in blood and stroke volume, blood pressure, and reduced exercise capacity...In addition to muscle loss, and apart from a deterioration of proper immune functioning during space travel, arguably the most fearsome effect on bodies is bone loss. Although their hardness and strength, and the relative ease with which they fossilize, give bones a reputation of permanence, bone is actually a living and remarkably flexible tissue....[I]n the gravity-free environments in space, bones will de-mineralize, especially in the lower limbs that normally counteract the effects of gravity. With considerable individual variation, during half a year in space, cosmonauts lost up to a quarter of the tibial bone material...What has been of greatest concern is that, unlike muscle loss that levels off with time, bone loss seems to continue steadily with 1-2% a month of weightlessness. During a 2-3 year mission to Mars, space travellers could lose up to 50% of their bone material, which would make it impossible to return to Earth's gravitational forces."
Who would have thought that the most formidable obstacle to space travel might not be the technological challenges, but the fact that our bodies are profoundly mal-adapted to the environment of space?
It isn't necessary to leave earth to encounter unusual environments. Six weeks in bed leads to similar atrophy of the heart as one week of space (p82). People didn't lay on their backs for six weeks in the Stone Age and our symphony of regulatory processes composed by natural selection was not written for this circumstance. In how many other ways does the modern human environment depart from the ancestral human environment, resulting is other regulatory mismatches?
All very interesting, you might be thinking, but how does it relate to the concept of regulation in politics and economics? They call it "body politic" for a reason. The regulatory processes required for a human society to work are no different than those required for a single organism to work. In fact, there is no difference at all between a well-functioning society and a single organism, as I will show in a future installment of this series. First, however, it is important to introduce another major theme -- the problem of cheating.
To be continued...
This article first appeared on Evolution: This View of Life
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