Design in Nature: How the Constructal Law Governs Evolution in Biology, Physics, Technology, and Social Organization - Hardcover

Bejan, Adrian; Zane, J. Peder

Hardcover

ISBN 10: 0385534612 ISBN 13: 9780385534611

Publisher: Doubleday, 2012

Synopsis

In this groundbreaking book, Adrian Bejan takes the recurring patterns in nature—trees, tributaries, air passages, neural networks, and lightning bolts—and reveals how a single principle of physics, the Constructal Law, accounts for the evolution of these and all other designs in our world.
 
Everything—from biological life to inanimate systems—generates shape and structure and evolves in a sequence of ever-improving designs in order to facilitate flow. River basins, cardiovascular systems, and bolts of lightning are very efficient flow systems to move a current—of water, blood, or electricity. Likewise, the more complex architecture of animals evolve to cover greater distance per unit of useful energy, or increase their flow across the land. Such designs also appear in human organizations, like the hierarchical "flowcharts" or reporting structures in corporations and political bodies.

All are governed by the same principle, known as the Constructal Law, and configure and reconfigure themselves over time to flow more efficiently. Written in an easy style that achieves clarity without sacrificing complexity, Design in Nature is a paradigm-shifting book that will fundamentally transform our understanding of the world around us.

About this title

About the Author:

ADRIAN BEJAN is Duke University's J. A. Jones Professor of Mechanical Engineering.

J. PEDER ZANE is an award-winning columnist who has worked for the New York Times and the Raleigh News.

Excerpt. © Reprinted by permission. All rights reserved.:

Discovering a unifying law of design in nature was not on my to-do list when I traveled to Nancy, France, in late September 1995. I was a forty-seven-year-old professor of mechanical engi- neering at Duke University who had come to deliver a lecture at an international conference on thermodynamics. Giving you a sense of how steeped my career was in mechanical engineering, I remember that I had brought flyers announcing the publication of my seventh book, Entropy Generation Minimization.

My work took a fateful turn during the prebanquet speech delivered by the Belgian Nobel laureate Ilya Prigogine. Echo- ing the scientific community’s conventional wisdom, this famous man  asserted  that  the  tree-shaped  structures  that  abound  in nature—including river basins and deltas, the air passages in our lungs,  and lightning bolts—were  aléatoires  (the result  of throw- ing the dice). That is, there is nothing underlying their similar design. It’s just a cosmic coincidence.

When he made that statement, something clicked, the penny dropped. I knew that Prigogine, and everyone else, was wrong. They weren’t  blind; the similarities among these  treelike struc- tures are clear to the naked eye. What they couldn’t see was the scientific principle that governs the design of these diverse phe- nomena. In a flash, I realized that the world was not formed by random accidents, chance, and fate but that behind the dizzying diversity is a seamless stream of predictable patterns.

As these thoughts began to flow, I started down a long, uncharted, and wondrously exciting path that would allow me to see the world in a new, and better, light. In the sixteen years since, I have shown how a single law of physics shapes the design of all around us. This insight would lead me to challenge many articles of faith held by my scientific  colleagues,  including the bedrock beliefs  that biological creatures  like you and me are governed by different principles  from  the inanimate world of winds  and rivers  and the engineered world of airplanes,  ships,
and automobiles. Over time, I would develop a new understand- ing of evolutionary phenomena and the oneness of nature that would reveal how design emerges without an intelligent designer. I would also offer a new theory for the history of Earth and what it means to be alive.

In addition, I and a growing number of scientists around the world would begin finding new ways to make life easier: better ways to design roads and transport systems; to predict the evolution of civilization and science, of cities, universities, sports, and the global use of energy. We would unravel the mysteries of Egypt’s Pyramids and the genius of the Eiffel Tower while demonstrating how governments  are designed  like river basins and how busi- nesses are as interdependent as the trees on the forest floor.

All that lay in the future when I boarded the plane for the trip home. High over the Atlantic, I opened my notebook (the old- fashioned kind, with paper) and wrote down the constructal law:
 
For a finite-size  flow system  to persist in time (to live), its configuration must evolve in such a way that provides easier access to the currents that flow through it.
 
I was writing in the language of science, but the fundamental idea is this:  Everything that moves,  whether animate or inani- mate, is a flow system. All flow systems generate shape and struc- ture in time in order to facilitate this movement across a landscape filled with resistance (for example, friction). The designs we see in nature are not the result of chance. They arise naturally, spon- taneously, because they enhance access to flow in time.
Flow systems have two basic features (properties). There is the current that is flowing (for example, fluid, heat, mass, or infor- mation) and the design through which it flows.

A lightning bolt, for example, is a flow system for discharging  electricity from a cloud. In a flash it creates a brilliant branched structure because this is a very efficient way to move a current (electricity) from a volume (the cloud) to a point (the church steeple or another cloud). A river basin’s evolution produces a similar architecture because  it, too, is moving a current (water) from  an area (the plain) to a point (the river mouth). We also find a treelike struc- ture in the air passages of lungs (a flow system for oxygen), in the capillaries (a flow system for blood), and the dendrites of neurons in our brains  (a flow system for  electrical signals and images). This treelike pattern emerges throughout nature because it is an effective design  for facilitating point-to-area and area-to-point flows. Indeed, wherever you find such flows, you find a treelike structure.

Since human beings  are part of nature and governed by its laws, the point-to-area and area-to-point flows we construct also tend to have treelike structures. These include the transportation routes we follow to work (a flow system for moving people and goods), which include many smaller driveways and neighborhood paths flowing into a few larger roads and highways. So, too, do the flowing networks of information,  material, employees,  and customers that keep those businesses afloat. The engineered world we have built so that we can move more easily does not copy any part of the natural design;  it is a manifestation of it. That said, once we know the principle, we can use it to improve our designs.

Although treelike structures are a very common design in nature, they are only one manifestation of the constructal law. In a simple example, logs floating on a lake or icebergs at sea ori- ent themselves perpendicular to the wind in order to facilitate the transfer  of motion from  the moving air body to the water body. A more complex example  is the design of animals that have evolved to move mass better and better (to cover more distance per unit of useful energy) across the landscape. This includes the seemingly “characteristic”  sizes of  organs,  the shape of bones, the rhythm of breathing lungs and beating hearts, of undulating tails, running legs, and flapping wings. All these  designs have arisen—and work together—to allow animals, like raindrops in a river basin, to move more easily across a landscape.

The constructal law dictates that flow systems should evolve over time, acquiring better and better configurations to provide more access for the currents that flow through them. Design gen- eration and evolution are macroscopic  physics phenomena that arise naturally to provide better and better flow access to the currents that run through them. The majesty of this principle is that it occurs at every scale. Each component of an evolving flow system—each  rivulet, each tree, each road—acquires  evolving designs to facilitate flow access. As these elements coalesce into larger and larger structures  (into evolving river basins, forests, and transport networks),  the  various-sized  components  work
together so that everything flows  more easily. We see this,  for example, in the shape and structure of the neural networks  in the brain, of the alveoli in the lung, and the human settlements on a map. In the big picture, all the mating and morphing flows on the largest system that surrounds us, the Earth itself, evolve to enhance global flow. E pluribus unum (one out of many).

The constructal  law is revolutionary because  it is a law of physics—and not just of biology, hydrology, geology, geophys- ics, or engineering. It governs any system, any time, anywhere, encompassing  inanimate (rivers  and lightning bolts),  animate (trees,  animals),  and engineered (technology) phenomena, as well as the evolving flows of social constructs such as knowledge, language, and culture. All designs arise and evolve according to the same law.
This  law tears  down the walls that have separated the disci- plines  of science by providing a new understanding  of what it means to be alive. Life is movement and the constant morphing of the design of this movement. To be alive is to keep on flow- ing and morphing. When a system stops flowing and morphing, it is dead. Thus, river basins configure and reconfigure them- selves to persist in time. When they stop flowing and morphing they become dry riverbeds, that is, the fossilized remains of earlier “live” flow systems. The solid, treelike veins of ore found under- ground today, for example, are fossils of the fluid streams, eddies, and meanders that flowed before solidification a long time ago. Biological creatures are alive until all their flows (blood, oxygen, locomotion, and so on) stop, after which they, too, become fos- silized remains.

This unifying definition marks an advance because it removes the concept of life from  the specialized domain of biology. It aligns  it (or, better, it juxtaposes  it) with the physics concept of the dead state, which means “equilibrium with the environ- ment”  in thermodynamics:  a system  that is  at the same  pres- sure, the same temperature, and so forth as its surroundings, and hence, in which nothing  moves. The  constructal  law defines
life in physics terms,  and it covers  all live-system  phenomena. It also reframes the view that life on Earth began with the rise of primitive species some 3.5 billion years ago. As we will see, “life” began much earlier, when the first inanimate systems, such as currents of solar heat and wind, acquired evolving designs. In the big history of life on Earth, the emergence and evolution of inanimate, animate, and technological designs tell a single story. Where Darwin showed the links  between biological creatures, the constructal law connects everything on the planet.

On one level, the constructal law can be expressed through the language of mathematics, physics, and engineering. My col- leagues and I have published hundreds of articles in leading peer- reviewed journals.  My  own  books  for  specialists—including Advanced  Engineering  Thermodynamics;  Shape  and  Structure,  from Engineering to Nature; and Design with Constructal Theory—use the constructal law to predict the phenomenon of design configura- tion. Leading universities, from Paris and Lausanne to Shanghai and Pretoria, have hosted international conferences and courses on the constructal law.

You don’t  need advanced mathematics  to grasp it. The con- structal law is also a way of seeing. Since discovering the law, I have witnessed  thousands  of people—from  renowned scholars and professional scientists to my students at Duke and those at high schools I’ve visited—experience a moment of discovery like the one I had in Nancy. They, too, hear the penny drop. They see it. They get it. Through this book I hope to help you recog- nize how the constructal law is shaping everything around—and within—you.

Seeing constructally can be thought of as a three-step process. Step one starts with Leonardo da Vinci’s insight that “motion is the cause of every life.” I love this quote because it is so expan- sive. And yet, Leonardo didn’t take it far enough, because he was talking only about biological creatures. In fact, not  only ani- mals but also rivers, weather patterns, snowflakes, corporations, nations, science, knowledge, culture—you name it—throb and pulse with movement.

Even things that seem just to sit there are, in fact, flow systems. Take that quintessence of stagnation, the mud puddle. There it sits, murky and soupy. And yet, when the sun emerges after the rain, dry air begins to draw moisture from it because of the natu- ral tendency toward equilibrium (in this case, of wet and dry). Before long, the puddle is gone. Soon the dirt begins to crack in telltale, treelike patterns in order to facilitate the flow of mois- ture from the ground to the air. That puddle is, in fact, a vibrant, morphing flow system. If we trained a movie camera on it, we’d see plenty of action.

Human beings are also flow systems, similar to but more com- plex than mud cracks. Internally, the flow of blood carries oxygen and food through a treelike network of blood vessels to organs whose size and shape are just right to enable us to move efficiently per amount of useful energy derived from food. The design of our bodies—just like that of every other animal from sharks to antelopes  to great blue herons  as well as that of trucks  on the highway—has evolved to enable us to cover greater distances per unit of useful  energy (food,  fuel). And, like trees  in the forest, we are also part of other, much larger, flow systems on Earth. When we get in cars, we enter the flow of traffic. In the office, the work we produce flows along with that of coworkers to reach customers through various channels. At the supermarket, tea that flowed from farmers and distributors in Sri Lanka settles into our shopping baskets. As we will see, all these seemingly independent designs are morphing and mating to facilitate our movement.

Step two is to recognize that all flow systems have the ten- dency to endow themselves  with a characteristic that was not recognized until the constructal law—design. This property includes the flow system’s configuration (the architecture, geom- etry, shape, and structure) and its rhythm (the predictable rate at which it pulses and moves).
Design does not emerge willy-nilly. To know why things look the way they do, first recognize what flows  through them and then think of what shape and structure should emerge to facili- tate that flow. The configuration of a flow system is not a periph- eral feature. It is the defining characteristic. In later chapters we will illustrate this  by showing how the shape and structure of seemingly disparate phenomena—including rivers, fish, sprinters, economies, universities, and the Internet—are predicted by the constructal law.

Step three turns  our drawing into a movie because  designs evolve. Flow systems configure and reconfigure themselves over time. This evolution occurs in one direction: Flow designs get measurably better, moving more easily and farther if possible. Of course, there will be bumps  and mistakes:  Every trial involves error. But in broad terms, tomorrow’s system should flow better than today’s.

This  is  the natural phenomenon  covered by the constructal law: the generation, ceaseless morphing, and improvement of flow design. This mental viewing enables us to recognize that people, birds, and other animals are flow systems that carry mass on the surface of the globe; that trees and mud cracks are flow systems for moving water from  the ground to the air; that universities, newspapers, and books are flow systems for spreading knowledge across the ...

About this edition

• Publisher: Doubleday
• Publication date: 2012
• ISBN 10: 0385534612
• ISBN 13: 9780385534611
• Binding: Hardcover
• Edition number: 1
• Number of pages: 304