Life thrives. It flourishes almost everywhere we look, even in remarkably inhospitable places. Perhaps because life is so common, it’s easy to lose sight of how tenuous it is. Life depends on a delicate balance of forces. Tip that balance and death is inevitable.
Howard Glicksman’s profound 81-part series, The Designed Body, concluded last September here at Evolution News. Dr. Glicksman offers uncommon insights into the inner workings of the human body (i.e., this thing I’m trapped inside of). As a hospice physician, he understands what it takes for a human body to survive, and how various dysfunctions can foul up the works and cause death. He makes these easy to understand, and offers important lessons for readers willing to work their way through the medical bits. I would like to add here my own reflections on the subject.
The series by Dr. Glicksman discusses 40 interrelated chemical and physiological parameters that the human body must carefully balance to sustain life. The body deploys amazing, interconnected solutions to manage them.
The parameters are: (1) oxygen, (2) carbon dioxide, (3) hydrogen ion, (4) water, (5) sodium, (6) potassium, (7) glucose, (8) calcium, (9) iron, (10) ammonia, (11) albumin transport, (12) proteins, (13) insulin, (14) glucagon, (15) thyroid hormone, (16) cortisol, (17) testosterone, (18) estrogen, (19) aldosterone, (20) parathormone, (21) digestive enzymes, (22) bile, (23) red blood cells, (24) white blood cells, (25) platelets, (26) clotting factors, (27) anti-clotting factors, (28) complement, (29) antibodies, (30) temperature, (31) heart rate, (32) respiratory rate, (33) blood pressure, (34) lung volume, (35) airway velocity, (36) cardiac output, (37) liver function, (38) kidney function, (39) hypothalamic function, (40) nerve impulse velocity.
I drew seven insights from the series.
Life can only exist when swimming upstream against uncharitable natural forces.
To survive, a human body must constantly struggle against powerful and unrelenting natural forces. When the body succumbs to any one of these forces, it reaches equilibrium with the environment — a condition commonly known as “death.”
A complex body plan places enormous demands on survival.
Single-celled organisms can only survive in a suitable substrate — where the organism (cell) is in direct contact with the environment, from which it must draw all the raw materials it needs to survive, and into which it can shunt its waste products without being poisoned by them.
In contrast, the vast majority of the cells in the human body are physically isolated from the environment, so survival depends on other means to deliver the needed raw materials and slough off any toxic waste materials for each one of its trillions of cells. Controlling so many factors is complicated work, and takes a lot of systems.
Goldilocks or death.
For each of these 40 chemical and physiological factors, the body must maintain its function within a narrow range of possible values. In effect, the body must do just the right things in just the right places at just the right times, in just the right quantities and at just the right speeds. Survival depends on maintaining balance within these tight tolerances.
This is an example of the Goldilocks Principle — everything must be just right for life to be possible. As Glicksman says, “Real numbers have real consequences.” When the numbers cannot be maintained at the right levels, the body dies.
As an example, let’s look at what’s needed for cellular respiration:
The cell is the basic building block of the human body. Each cell must successfully fight diffusion and osmosis in order to maintain its internal volume and required chemical content. This takes energy, which must come from somewhere.
To meet its energy needs, the cell breaks down glucose according to a simple chemical formula: C6H12O6 + 6O2 = 6CO2 + 6H2O. The glucose molecule and six oxygen molecules are converted into six molecules of carbon dioxide and six molecules of water. These are all stable molecules, so it takes some doing to make this work. In a complex 3-stage process, the cell uses 20+ specialized enzymes and carrier molecules (each made up of 300+ specifically-ordered amino acids), to break down the chemical bonds of the glucose molecule, thereby releasing energy which the cell uses to operate its machinery, including the critical sodium-potassium pumps that control the cell’s content and volume.
Obviously, a supply of oxygen is essential. But this presents a few problems for the body. While glucose can be stored in the body for later use, oxygen can’t, so it must be supplied continuously, and in the right quantities to meet current demand.
Without enough oxygen, the cell runs out of energy, its sodium-potassium pumps fail, the cell’s internal volume and chemical content can’t be maintained, and the cell dies. When sufficient cells within an organ die, the functions provided by that organ cease, causing downstream functions to fail, and so on. Without corrective action, this leads to a chain reaction of failure. In just a few minutes a lack of oxygen will kill the entire body.
On the other hand, when the body gets enough oxygen, the process generates carbon dioxide, which, if not removed, elevates the cell’s hydrogen ion level, which leads to cell death.
So the cell must efficiently “gate” oxygen into the cell and carbon dioxide out of the cell through the cell membrane. Given that the cell is surrounded by a few trillion other cells, each of which is independently maintaining the same cell content and volume functions, the body must manage overall substantive flows of oxygen (in) and carbon dioxide (out).
This requires an efficient transport subsystem (e.g., a circulatory system), complete with a pump (heart), transport medium (blood), and means to exchange oxygen and carbon dioxide with the air in the environment (lungs).
But this is not so easy. Blood’s fluid component is mainly water, and oxygen doesn’t dissolve well in water. So the body adds a complex iron-based protein called hemoglobin to the blood, which binds to the oxygen so it can be transported efficiently throughout the body. To make this work, though, the body needs still other (sub)systems to acquire, store, and process just enough iron (too much is toxic), and then process it into hemoglobin.
And there’s a separate process and subsystems to deliver glucose to the cells. Glicksman gives a lot more detail, but you get the idea: a lot of moving parts are required.
Survival depends on specialization, integration, and coordination.
Solving these problems in practice gets tricky.
To achieve the large variety of functions needed for survival, the body uses around 200 different, specialized types of cells. To achieve the requisite function for each body subsystem, these cells must be arrayed in just the right locations with respect to their relevant subsystem(s).
Only when each subsystem is properly arrayed and functioning can the body survive. But solutions at the subsystem level tend to present new problems to overcome, and these typically rely on other autonomous subsystems, which are comprised of other specialized cells that are arranged in just the right ways to achieve their function. All of these must coordinate with each other.
In the example above, the circulatory subsystem transports raw materials to those trillions of individual cells. But inertia, friction, and gravity present challenges to circulation, so the system needs additional control mechanisms, involving cardiac output, blood pressure, and blood flow, to ensure that circulation is effective throughout the body.
A human body must operate effectively in at least three different levels: (1) the cells, (2) the subsystems, and (3) the whole body. The challenge to craft effective mechanisms across all three levels to address all 40 survival parameters is mind-boggling, and the body has somehow acquired ingenious solutions.
Every one of the body’s control systems is irreducibly complex.
For each of the 40 survival factors, the human body requires at least one control system. Every control system, whether in a biological or a human-engineered system, must include some means to perform each of the following functions:
- Sensors, to measure that which is being controlled. There must be enough sensors, in the right locations (to sense that which is being controlled), and with suitable sensitivity to the needed tolerances.
- Data integrators, to combine data from many sensors.
- Control logic, to determine what adjustments are needed to achieve the desired effects. In some cases the logic may drive changes across multiple subsystems. In all cases, the logic must be correct to achieve proper function.
- Effectors, to modify that which is being controlled.
- Signaling infrastructure, to carry signals from the sensors to the data integrator(s) and/or controller, and from the controller to the effectors. Signals must carry the correct information, be directed to the right components, and arrive in a timely fashion.
Effectors must be capable of some or all of the following functions (depending on the factor being controlled):
- Receptors, to receive signals regarding adjustments that must be made.
- An organ, tissue, or other body subsystem capable of affecting the factor being controlled.
- Harvesters, to obtain any needed chemicals from the environment — in the right amounts, at the right times — and convert them as needed for a particular use (eg, iron into hemoglobin).
- Garbage collection, to expel unneeded chemical byproducts, which may be toxic in sufficient quantities.
Each control system must be dynamic enough to maintain the tight tolerances required in the timeframes needed. For example, it just wouldn’t do for the oxygen control system to take ten minutes to increase oxygen levels, if the body will die in four minutes without more oxygen.
Every one of the body’s control systems uses hundreds to millions of individual parts. This is irreducible complexity on steroids.
The body is a coherent mesh of interdependent systems.
None of the control systems Glicksman describes can achieve its functions alone — each relies on other body subsystems for help. To achieve this, the control mechanisms must work together toward an outcome that none can “see” or control end to end. Together, they form a mesh of interlocking control systems.
The human body is a coherent assembly of interdependent subsystems. Each subsystem is a coherent system in its own right, made up of an assembly of lower level components. Each lower level component is itself an assembly of even lower level components. We can follow this composition pattern of assembled components all the way down to proteins, amino acids, and the DNA code.
And, lest this be too easy, functional coherence requires process coherence across the body’s lifecycle, from fertilization to maturity and reproduction. Process coherence further constrains the body’s systems, and makes survival even more difficult.
Coherence requires all the right parts in all the right places doing all the rights things at all the right times in all the right quantities at all the right speeds — together, as a whole. This means the correct relative locations, sizes, shapes, orientations, capacities, and dynamics, with the correct fabrication specifications, assembly instructions, and operating processes. To coordinate its internal activities, the body integrates its parts and communicates using multiple types of signaling (eg, point-to-point, multi-point, broadcast). To maintain function, it uses still other mechanisms for error correction, failure prevention, threat detection, and defense, throughout its many levels of systems and subsystems.
The body’s parts are functionally interdependent, yet operationally autonomous. Aside from being extraordinarily hard to achieve with so many moving parts, this is what an engineer would call elegant design. The architecture of the human body is exquisite.
The whole is greater than the sum of the parts.
For the human body, though, the whole is much more than the sum of its parts. This is exactly what we see with all complex engineered systems. In fact, this is a defining characteristic of engineered systems.
With humans, the whole is also quite remarkable in its own right. It’s almost as if the body was designed specifically to enable the mind: thought, language, love, nobility, self-sacrifice, art, creativity, industry, and my favorite enigma (for Darwinists): music.
The human body enables these things, but does not determine them. As near as we can tell, no combination of the body’s substrate — information, machinery, or operations — alone can achieve these things.
Yet it’s exactly these things that make human life worth living. These are essential to our human experience. Human life involves so much more than merely being alive.
This simple observation flies in the face of Darwinian expectations. How can bottom-up, random processes possibly achieve such exquisitely engineered outcomes — outcomes that deliver a life experience well beyond the chemistry and physics of the body?
Such questions have enormous implications for worldviews, and for the ways that humans live their lives. I’ll look at some of those in a further post tomorrow.