If you want to find alien life-forms, hold off on booking that trip to the moons of Saturn. You may only need to catch a plane to East Lansing, Michigan.

The aliens of East Lansing are not made of carbon and water. They have no DNA. Billions of them are quietly colonizing a cluster of 200computers in the basement of the Plant and Soil Sciences building at Michigan State University. To peer into their world, however, you have to walk a few blocks west on Wilson Road to the engineering department and visit the Digital Evolution Laboratory. Here you'll find a crew of computer scientists, biologists, and even a philosopher or two gazing at computer monitors, watching the evolution of bizarre new life-forms.

These are digital organisms-strings of commands-akin to computer viruses. Each organism can produce tens of thousands of copies of itself within a matter of minutes. Unlike computer viruses, however, they are made up of digital bits that can mutate in much the same way DNA mutates. A software program called Avida allows researchers to track the birth, life, and death of generation after generation of the digital organisms by scanning columns of numbers that pour down a computer screen like waterfalls.

After more than a decade of development, Avida's digital organisms are now getting close to fulfilling the definition of biological life. “More and more of the features that biologists have said were necessary for life we can check off,” says Robert Pennock, a philosopher at Michigan State and a member of the Avida team. “Does this, does that, does this. Metabolism? Maybe not quite yet, but getting pretty close.”

One thing the digital organisms do particularly well is evolve.“ Avida is not a simulation of evolution; it is an instance of it,” Pennock says. “All the core parts of the Darwinian process are there. These things replicate, they mutate, they are competing with one another. The very process of natural selection is happening there. If that's central to the definition of life, then these things count.”

In finding an answer to “perhaps the greatest unsolved ecological riddle,” evolutionists propose that diversity is a testament to there being more than one way to make a living.

The riddle: Why are some habitats loaded with many more species than others?

The answer: Nature and evolution respect that there’s more than one way of doing things.

“What we’ve learned,” said Michigan State University scientist Charles Ofria, “is that if there isn’t just one way to succeed, you’ll see diversity.”

In an article published in the July 2 issue of Science, an interdisciplinary team of scientists at MSU, the California Institute of Technology and Keck Graduate Institute (KGI), with the help of powerful computers, has used a kind of artificial life, or ALife, to gain insight into questions of evolution.

Ecology has always lacked a strong overarching theory like those behind physics or chemistry. But no longer, thanks to the universal throttle inside every living thing, say ecologist James Brown and physicist Geoffrey West

If you want to experience the diversity and complexity of life, walk into any forest anywhere in the world. Most revealing would be a tropical forest in Brazil, New Guinea or the Congo. Look at the birds, butterflies, ants and plants. Listen to the sounds of animals you cannot see. In just half a hectare there may be more than 1000 individuals of 100 different tree species and millions of individuals representing thousands of insect species. Is there any order to this jumble? It is hard to imagine learning the rules to the games all these organisms are playing.

Of course, any ecologist will tell you we can work out a few of the rules. This insect pollinates this tree; that one feeds on its leaves. Some plants are short-lived weedy opportunists; others grow slowly but live for centuries. But almost all such rules apply only to a specific collection of species in a particular place and time. Look elsewhere - sometimes even just the next river basin - and the rules are different. Despite a hundred years of research, ecology has little in the way of universal laws or principles like the laws of gravity and thermodynamics in physics or the Mendelian laws of inheritance in biology. Is ecology really devoid of universal laws?

We think not. The laws are there, just waiting to be discovered. In the past few years we have been leading a unique collaboration of biologists and physicists that has been investigating the forces behind a host of ecological patterns, and we have identified one factor that seems to have dramatic ecological consequences: metabolic rates, the rates at which organisms use energy and materials. Our developing "metabolic theory of ecology" has already provided powerful general explanations for how metabolic rate changes with the body size and temperature of animals, plants and microbes. It also predicts and explains many simple and regular relationships - akin to the overarching laws in other areas of science.

The building blocks of life pervade the solar system, and probably the universe, locked up in planetary polar ice caps, crouching in the interstices of ancient volcanic rocks, zooming around on comets and meteorites, drifting between galaxies in interstellar space, or wafting gently down in cosmic dust.

"The universe is hard-wired to form a lot of the compounds that make life," says astrophysicist Scott A. Sandford of NASA's Ames Research Center. "But that doesn't mean it's happening. There may be a lot of places where the process gets frustrated, and since we haven't seen it on any planet except our own, it's just a story."

I am a passenger on the spaceship, Earth.
- Buckminster Fuller

Investigations
By Stuart A. Kauffman
Copyright 2000

There are living systems; there is no "living matter".
- Jacques Lucien Monod

Evolution's Arrow: The Direction of Evolution and the Future of Humanity
By John Stewart
Copyright 2000

The Origins of Order: Self-Organization and Selection in Evolution
By Stuart A. Kauffman
Copyright 1993

Life Itself: A Comprehensive Inquiry Into Nature, Origin, and Fabrication of Life

By Robert Rosen

Copyright 1991