The Bare Essentials of Life

The Shape Of Nature

Modern anatomy has taken many centuries to accumulate a body of knowledge that is now unrivalled in any other sphere. It has classified structures according to the thinking of the day and sought to understand their functions using the latest technologies, but established conventions have allowed many inconsistencies to survive long past their sell by dates.  For example, orthodox views of human movement are based on the mechanics of man-made machines described in the seventeenth century and have remained essentially unchanged ever since, but biology is not constrained by the rules of classical mechanics and there is now a better way of looking at functional anatomy that is founded on some basic principles of self-organization.

IcosahedronWhenever nature uses the same principle in a variety of different situations there is probably an underlying energetic advantage to its appearance, and biological development and evolution will always favour those patterns and shapes that are the most energy-efficient in terms of stability, materials and mass. Even though they can appear to be rather complicated, at the most basic level, all living structures are the result of interactions between atomic forces and the orderly arrangements that they settle into.

Atoms interact with each other in many different ways – Van der Waal forces, electrostatics, covalency, steric interactions etc – but these can all be simplified into ‘those that attract’ and ‘those that repel’. The ‘forces’ themselves are invisible but ultimately cause the atoms to spontaneously form recognizable and tangible structures (crystals and molecules) through some basic principles of self-organization: geodesic geometry, close-packing and minimal-energy; and the same principles apply at every size scale where these ‘forces’ are frequently referred to as tension and compression. Thus, while the body itself has long been considered as a physical structure, a biotensegrity perspective recognizes that the particular configuration of invisible forces within it (closed-chain kinematics/tensegrity) is much more important in understanding what really enables it to do all the things it does. Living structures are the physical representations of the invisible forces within them.

Nature always does things in the simplest and most energy-efficient way possible, and a proper understanding of this simplicity now provides a powerful means to relate complex patterns and shapes with functional anatomy. Albert Einstein emphasized that the laws of physics must be the same in every place, which means that even the most complex organisms can be understood in terms of the same basic rules of organization.

Biotensegrity (modified from Bare Essentials 2014 issue 37)

Horse ImageBiotensegrity recognizes that the forces of attraction and repulsion at the molecular scale are comparable with those of tension and compression at higher size scales, and are easily modelled using cables and struts, respectively. It is a simple re-evaluation of anatomy as a network of structures under tension and others that are compressed; parts that pull things together and others that keep them apart; basic physics!

Tensegrity models are similar to biological structures in that they are strong, light in weight and resilient to the effects of damaging forces, yet can change shape with the minimum of effort and always return to the same position of stable equilibrium. Their structural mechanics operate the same in any position, irrespective of the direction of gravity, and they have similar non-linear properties that influence movement and relate more to the newly-emerging field of soft-matter physics than classical mechanics. Each component part can be constructed from smaller ones within a complex structural heterarchy and innumerable hierarchies within it, with each part functionally related to all the others (because that is how they formed in the same place) so that the entire structure becomes united into a single functioning unit.

The recognition of biotensegrity as a unifying structural principle in living organisms began in the mid 1970’s with Stephen M. Levin (b. 1932), an orthopaedic surgeon who observed things at the operating table that could not be explained through orthodox biomechanical theory. He found that tightening up certain ligaments in the knee etc caused the bones to move apart, and that normal bones did not compress each other across their articular surfaces and often had a slight spacing between them, but there was no known mechanism that could make this possible; it was like the bones were suspended or appeared to ‘float’ within the tensional network of soft tissues. Further research on the skeletons of dinosaurs and other large animals eventually led to the realization that a then relatively little known structural principle called ‘tensegrity’ could provide an explanation for these findings and could be applied to every part of the body.

needleThe term ‘tensegrity’ is a combination of the words tension and integrity, and this structural system was first recognized as a new structural principle in 1948 by Kenneth Snelson (1927-2016), a young sculptor who produced many impressive works that he described as “…unveil[ing] the exquisite beauty of structure itself”. Tensegrity models are particularly interesting because the struts remain isolated and do not compress each other at any point because they are suspended within the tension network. The architect Buckminster Fuller (1895-1983) recognized them as part of his theory of Synergetics, the study of nature’s coordinate system that considers that all natural structures are inherent displays of the forces within them; and the cell biologist, Donald Ingber, has described the structural lattice (cytoskeleton) within cells as a tensegrity structure that regulates cell function and applies at every size scale in the body. Mechanical engineers also appreciate the distinctive properties of tensegrity structures and are producing robots for use in the exploration of space etc. Both biologists and engineers now recognize that the simple principles of tensegrity can be applied to understanding the behaviour of more complex structures, but because certain aspects are not transferable between these different fields, Stephen Levin introduced the term biotensegrity to distinguish between them.

Biotensegrity models emulate biology in ways that were inconceivable in the past, but it has taken some time for the concept to become widely accepted because of its challenges to generally accepted wisdom. Biotensegrity explains how ‘joints’ can remain completely stable without over-stressing the soft tissues surrounding them, and demonstrates that the spine is essentially a tensioned structure that can function much the same in any position, with movement controlled by the very structure itself. It is attracting the attention of engineers, biologists, hands-on and movement therapists because it provides a better means to visualize the mechanics of the body in the light of new understandings about functional anatomy.

A note on the so-called power laws:


So-called ‘power-laws’ are interesting because they offer an apparent link between complex and diverse phenomena, but their place in the grand scheme of things should be recognized for what it really is. While physicists and biomechanics use a system of engineering-based structural analysis for understanding natural phenomena based on equations, the underlying simplicity that underlies everything in the universe – geodesic geometry, close-packing and minimal-energy – is generally disregarded.

Investigations into biological organization have mostly started at the complex cellular level and moved upwards, and the power-scaling laws then emerge out of this, but recognizable patterns do not just appear out of nowhere but because of the interactions between some more basic principles described above.

Power-scaling patterns or ‘laws’ are a product of self-organized complexity but do not explain how or why the phenomena they link together developed in the first place. They are interesting and sometimes useful features in the emerging morphology but their significance has been overblown. In the same way, biological ‘fractals’ are not the result of some ongoing mathematical iteration but self-similar statistical probabilities that emerge independently as the developing structures formed. So, even though different processes at different size-scales can be compared through their fractal dimension, that does not necessarily mean that the structures themselvs are fractals. As for all those mathematical equations, they are simply subsets of the algorithms that determine how, why and in what way biology behaves in the way that it does, and are not causative in themselves.

  1. Levin, S.M. 2016. Tensegrity: the new biomechanics. In: M. Hutson and A. Ward, eds., Textbook of musculoskeletal medicine., 2nd Ed; Oxford: Oxford University Press.
  2. Scarr, G. 2018. Biotensegrity: the structural basis of life. 2nd ed., Edinburgh: Handspring.