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Fractals and the Laws of Life

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Santa Fe New Mexican

Geoffrey West takes fresh look at basic biology

By JEFF TOLLEFSON/The New Mexican November 19, 2001

Geoffrey West once spent his time breaking things down into universal building blocks. Atoms. Electrons. Quarks. Strings.

Like most physicists, he considered these particles and their behavior in a kind of scientifically imposed isolation from the rest of the world. He finds this kind of work interesting, even necessary, but somehow incomplete.
The British-born researcher has 26 years with Los Alamos National Laboratory under his belt, but over the years his interest has migrated from individual particles to complex organisms and ecosystems.

Enter the Santa Fe Institute, a scientific think tank that supports research in chaos and complexity theory. Tapping into the Santa Fe-based Thaw Charitable Trust, as well as government grants, West joined several scientists from different disciplines at the institute and pioneered a new approach to biology. That was about five years ago.

"We believe we have discovered some universal principles that apply across the great diversity of life."

That was West earlier this month, describing his work as he prepared for a series of public lectures sponsored by the Santa Fe Institute. He spent three evenings explaining the theory behind a set of remarkably simple algebraic equations that he and his colleagues have used to predict everything from how big organisms grow and how fast their hearts beat to how long they tend to live.

His work and that of others, including James Brown of The University of New Mexico and Brian Enquist of the University of Arizona, has been published in a series of peer-reviewed papers in the journals Nature and Science during the last several years. Recent articles have raised eyebrows in the scientific community, drawing enormous praise and skepticism.

Cornell University botanist Karl Niklas has said that the underlying theory could be as significant to the field of biology as Sir Isaac Newton's contributions were to physics. If the theory holds true, Niklas said in the Sept. 27 edition of Nature, it has "the potential to explain virtually everything."

West, 60, laughs when he hears such praise.

"Well, that's crazy. But it's marvelous," West said Tuesday at the
Santa Fe Institute. His corner office overlooks the town and the Jemez Mountains, where Los Alamos National Laboratory is visible on a clear day.

West said his work has him looking at the world in a new way. The Londoner earned his doctorate in physics at Stanford University - mostly an excuse to spend a year in California, he said.

He was enticed to Santa Fe by the lab in 1976 and never left. Several years ago he became serious about an old hobby: Thinking scientifically about the world around him.

"I realized that my whole career has been spent on abstractions," he says. "And of course I love abstractions, but there was something wonderful about being able to relate the abstractions to the stuff you touch and feel around you, the exquisite beauty of nature."


West began looking at that world through the lens of fractals. Think of the Grand Canyon; any arroyo outside of town is really a scaled-down version of the same thing.

Take a black-and-white photograph of both, without any references to scale, and the pictures would seem remarkably similar. This is why some detailed photographs include a distinguishable feature - a coin, knife or a hand - to help the viewer determine size.

Now think of your own cardiovascular system, which distributes energy equally and efficiently to the almost countless individual cells that collectively give you life.

Picture the large arteries leading from the heart and gradually branching out into capillaries that carry blood to individual cells throughout the body.

Compare that to a cottonwood tree, with its thick trunk gradually giving way to smaller and smaller limbs. The concept is much the same: It's a branching network that trees use to ensure proper distribution of energy.

West's research focuses on the similarities among these and other biological systems, from single-celled organisms to mammals, plants and ecosystems. Rather than studying the circulatory system of a horse, for instance, this approach scans all circulatory systems in an effort to discern and distill a simple truth.

The basic concept, known as scaling, posits that all life is governed by the same framework of physical laws. These laws constrain biological development, both allowing for and limiting growth.

And according to West and his colleagues, the rules that govern bushes and trees and mice and elephants are the same. The same algebraic equations that predict the size and heart rate of a cat also work for a rhinoceros. The larger organism, using this logic, is a scaled-up version of its smaller counterpart.

"And it works. That is the most amazing thing," West says. "In some ways, the biggest mystery of this work is, 'Why does it work so well?' "

What does this mean for you? For one thing, West explained to a packed house during the Santa Fe Institute's recent lecture series, the idea that people will continue to live longer and longer lives is probably a pipe dream. Biologically speaking, he said, all organisms are programmed to live and die, and the rate at which they do so is the same.

"A little mouse may only live two or three years, and a whale may live roughly 60, but they have the same number of heart beats. And that is roughly a billion. It's as if an organism of a given size has its own internal clock ticking away."

West presented a formula that takes into account energy consumption,
cellular growth and size of an organism to determine age. Graphing the results compared to age actual statistics, he presented a straight line from shrews to whales; humans figure in at about 40 years, which was about right before modern advances in cleanliness and medicine.

The trick to understanding scaling, West says, is knowing that everything does not scale equally according to size. Ants can carry many times their body weight. Horses can't. Birds eat more than their body weight each day. Elephants don't.

Since all animals are similar at the cellular level, that means the metabolism in larger animals is more efficient: Each cell is burning less energy. West says this is evolution at work. Furthermore, he notes that this shift in energy efficiency is governed by the same rules that govern size, heart rate and longevity. That means it can be predicted by similar algebraic equations.

In essence, he says, the biological system in larger animals somehow imposes efficiency gains on individual cells. Following this approach, scientists need to look at the whole system, because adding up the individual parts in a laboratory can produce "the wrong answer."

West says his work takes place where physics and biology interface. Physics is a science that is forever in search of, and bound by, fundamental rules. To date, he explained to his audience, biology has been geared more towards describing and understanding individual organisms.

This new approach uses mathematics, which West calls "the language of the universe," to describe fundamental principals that apply to everything "from microbes to elephants." Such an approach turns biology into a concrete science with the power to predict, West says.

"The basic message is that there are fundamental principals that unite all of life," he says with a chuckle, noting that it can be difficult to avoid clichés when describing such work. "It's very much this idea of seeing things, the interconnectedness of all life."

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