From Jones and Bartlett, a book on Stem Cells from Dr. Ann A. Kiessling and Scott C. Anderson:

Selected Articles:

December 20, 2003

Natural Complexity

Simple chemistry can provide some surprisingly complex shapes.

Living things are so extraordinarily complex, it's hard to imagine how the happenstance mechanics of Darwinian theory could have brought them into being. We know that the natural order of things -- loosely speaking -- is to get old, break down and turn to crap. So how is it that mere protoplasm has been able to organize itself so successfully that there has been an unbroken chain of life on this planet for over 500 million years?

This, of course, is the cry of the creationist as well. Surely this marvelous complexity is a sign of the hand of god. The nucleus of a cell, for instance, puts the finest Swiss watch to shame when it comes to complexity. The nucleus is a sphere pockmarked with daisy-like pores made of large, intricate proteins. These pores decide what molecules will be allowed to pass through the nuclear membrane. A nucleus has hundreds or thousands of these pores, each acting as a tiny immigration station, checking molecular identities and letting some through, while sending others back.

A cell, cut away to expose the pore-studded nucleus

How on earth could such a structure have evolved by chance alone? Who could possibly believe that any number of tiny improvements could ever give rise to such a beautiful and useful structure?

There are people who insist that the number of interdependent parts of the nucleus proves the case for an "intelligent designer." They propose that an object like a nucleus is "irreducibly complex." By that they mean that it's impossible to concoct a believable scenario of how -- obeying simple laws of nature -- a tiny sphere could combine with all these pores to form a vital, living membrane. Surely this arrangement would require powers far outside the hit-or-miss process of evolution. Just as it is highly improbable that a space shuttle (or even a humble mousetrap) would sprout naturally from a tree, how could we presume that a cell nucleus could exist without a designer? That's why a recent report on "blue water" is so astonishing (Nature: November 6, 2003).

Native Americans first discovered the blue water, which seeps out of certain mountains in the western U.S., centuries ago. Blue water forms naturally when the mineral molybdenite oxidizes. Water flowing through molybdenite deposits picks up the mineral and turns a rich blue color. Investigating the mysterious native reports in the early 1800s, scientists discovered that the blue water contains molecules with huge clusters of molybdenum and oxygen. When these clusters get big enough, they form a semi-stable molecular doughnut containing 154 molybdenum atoms. This is a pretty impressive feat for such simple chemistry, but this is just the beginning of the story.

It turns out that these doughnuts like to hang out together, and when there are a thousand of them or so they join up, spontaneously forming a hollow sphere. To a biologist, this should be a familiar structure.

Although smaller than a cellular nucleus, it has remarkable similarities. It has a naturally spherical shape, and it is composed of complex circular, pore-like subunits.

Among other things, it shows how incredibly complicated objects can be created with ordinary inorganic chemistry. This represents a breakthrough in the study of nanotechnology, because molecules of this size and structure could be very useful for hundreds of applications. But from an evolutionary point of view, it also represents an exciting glimpse into what the actual building blocks of biology might be. It now appears that they may already have as much complexity as we would ordinarily grant to biological items.

This pretty blue ball isn't alive, of course. And whether it has any connection at all to an actual nucleus is dubious. But it shows us how little we know about natural complexity. That a batch of molecular doughnuts would self-assemble into a tiny sphere is a wake-up call to those who feel that ordinary chemistry will not suffice to explain life. As this discovery amply demonstrates, a startling amount of complexity is simply par for the course.


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Here are some other suggested readings about complexity: