theories of self-organizing systems discussed in the previous chapters of this book provide the elements for formulating such a theory . 8 Prigogine’s theory of dissipative structures shows how complex biochemical systems, operating far from equilibrium, generate catalytic loops that lead to instabilities and can produce new structures of higher order. Manfred Eigen has suggested that similar catalytic cycles may have formed before the emergence of life on Earth, thus initiating a prebiological phase of evolution. Stuart Kauffman has used binary networks as mathematical models of the genetic networks of living organisms and was able to derive several known features of cell differentiation and evolution from these models. Humberto Maturana and Francisco Varela have described the process of evolution in terms of their theory of autopoiesis, seeing the evolutionary history of a species as the history of its structural coupling. And James Lovelock and Lynn Margulis in their Gaia theory have explored the planetary dimensions of the unfolding of life.
The Gaia theory, as well as the earlier work by Lynn Margulis in microbiology, have exposed the fallacy of the narrow Darwinian concept of adaptation. Throughout the living world evolution cannot be limited to the adaptation of organisms to their environment, because the environment itself is shaped by a network of living systems capable of adaptation and creativity. So, which adapts to which? Each to the other—they coevolve. As James Lovelock put it:
So closely coupled is the evolution of living organisms with the evolution of their environment that together they constitute a single evolutionary process . 9
Thus our focus is shifting from evolution to coevolution—an ongoing dance that proceeds through a subtle interplay of competition and cooperation, creation and mutual adaptation.
Avenues of Creativity
So the driving force of evolution, according to the emerging new theory, is to be found not in the chance events of random muta-
tions, but in life’s inherent tendency to create novelty, in the spontaneous emergence of increasing complexity and order. Once this fundamental new insight has been understood, we can then ask: What are the avenues in which evolution’s creativity expresses itself?
The answer to this question comes not only from molecular biology, but also, and even more importantly, from microbiology, from the study of the planetary web of the myriad microorganisms that were the only forms of life during the first two billion years of evolution. During those two billion years bacteria continually transformed the Earth’s surface and atmosphere and, in so doing, invented all of life’s essential biotechnologies, including fermentation, photosynthesis, nitrogen fixation, respiration, and rotary devices for rapid motion.
During the past three decades extensive research in microbiology has revealed three major avenues of evolution . 10 The first, but least important, is the random mutation of genes, the center- piece of neo-Darwinian theory. Gene mutation is caused by a chance error in the self-replication of DNA, when the two chains of the DNA’s double helix separate and each of them serves as a template for the construction of a new complementary chain . 11
It has been estimated that those chance errors occur at a rate of about one per several hundred million cells in each generation. This frequency does not seem to be sufficient to explain the evolution of the great diversity of life forms, given the well-known fact that most mutations are harmful and only very few result in useful variations.
In the case of bacteria the situation is different, because bacteria divide so rapidly. Fast bacteria can divide about every twenty minutes, so that in principle several billion individual bacteria can be generated from a single cell in less than a day . 12 Because of this enormous rate of reproduction, a single successful bacterial mutant can spread rapidly through its environment, and mutation is indeed an important evolutionary avenue for bacteria.
However, bacteria have developed a second avenue of evolutionary creativity that is vastly more effective than random mutation. They freely pass hereditary traits from one to another in a