Saturday, April 5, 2008

Biologists take evolution beyond Darwin

Nearly 150 years after Charles Darwin published On the Origin of Species, evolution has been widely accepted by scientists -- and, except for a few religious dogmatic types, the public -- as the blueprint for the engine of life. But not every scientist thinks that evolution as it's now understood and applied is complete. They want to scale it up to the level of populations, even whole ecosystems. Moreover, they say evolution is intertwined with other dynamics that science is just starting to understand. "The process of evolution is fundamental to the universe. Biology is the most obvious manifestation of it," said Carl Woese, a legendary microbiologist and one of the first proponents of this newly revised evolutionary framework. Darwin described how changes in an organism are passed from generation to generation, dwindling or spreading through populations depending on their contribution to survival. Biologists later combined this with genetics, which had yet to be discovered in Darwin's time. The fusion -- called the modern evolutionary synthesis, or neo-Darwinian evolution -- describes evolution as we now know it: Genetic mutations produce changes that sometimes become part of a species' heritage and, when enough changes accumulate, produce new species. But to Woese and others, change and selection need to be studied at other levels: A honeybee colony, for example, is as much an individual as a single bee. And when explaining how interacting units -- bees, or bacteria, or cells -- produce the qualities of the whole, change and selection alone might not suffice.

What's needed is an understanding of the dynamics of complexity. "There's nothing wrong with neo-Darwinian evolution in its own right," Woese said, "but it's not large enough to encompass what we know now." Woese's specialty is bacteria, and he's not afraid of bold theories that turn conventional scientific wisdom on its head. In 1977, he and colleague George Fox rearranged the animal kingdom from five branches into three, two of which comprise microbes

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