Monday, February 21, 2005

Gaia Hypothesis

I came across Jim Lovelock's "Gaia - A New Look at Life on Earth" from another book "Complexity - Life at the Edge of Chaos" by Roger Lewin. I bought this book from a few years ago. In the book, Lewin researched on life science and evolution based on the Chaos Theory. He used one whole chapter recording his meeting and the intimate discussion with Lovelock on his 1979 book and the Gaia Hypothesis. Lovelock particularly mentioned a section of the book on how the coming of the Homosapiens has changed the nature of Gaia, the Earth Goddess.

"She is now through us awake and aware of herself. She has seen the reflection of her fair face through the eyes of astronauts and the television cameras of orbiting spacecraft. Our sensation of wonder and pleasure, our capacity of conscious thought and speculation, our restless curiosity and drive are hers to share."

(portray of Jim Lovelock)

The Gaia Hypothesis states "Life, or the biosphere, regulates or maintains the climate and the atmospheric composition at an optimum for itself." It argued that the earth's biological and physical systems are tightly coupled in a giant homeostasis system. Gaia, in the language of complex systems, is regarded as a self-organized, giant self-regulating entity. The hypothesis received a lot of criticism, mainly because it defied the rule of evolution: the process of natural selection. Critics said that Earth could not evolve to such supposed adaptations, as there was no possibility of competition among Earth-like bodies. The notion that life changed Earth in an deliberately adaptive way in order to ensure its own existence was also under attack. People did not accept that there is a purposeful Gaia.

In 1981, Lovelock wrote a computer program of a population biology model, linking population of species with sunlight luminosity and global temperature. The model demonstrated the behaviour of complex adaptive systems, that such systems, like Gaia, were conducive to the emergence of homeostasis mechanisms. There is no need for a purposeful Gaia, or a being of higher intelligence. Gaia is just a complex adaptive system with life playing a part, together with the chemical and physical systems, to maintain an equilibrium for existence. However, the notion that Gaia, or mother Earth, being a superorganism, sentient and able to heal itself is still too much for some biologists.

Lovelock is steering the Gaia Hypothesis to the Gaia Theory. When questions raised by the hypothesis are answered and the theoretical framework is strengthened, the hypothesis will become theory. We shall have to wait and see how things develop. In the mean time, if you are really interested in the subject, try the books I mentioned above.

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