The Gaia Hypotheses: science or pseudoscience?
I have been rather skeptical of the so-called Gaia Hypothesis, the notion that planet Earth is one large, self-regulating organism, as opposed to the environment in which a number of ecosystems have evolved. The notion was first proposed by independent scientist James Lovelock in the 1970s, and co-developed by the controversial biologist Lynn Margulis, famous for having proposed that some cellular organelles, such as mitochondria and chloroplasts, initially evolved as endosymbionts, i.e., as functionally integrated organisms within organisms.
A few years ago I wrote an article for Skeptical Inquirer in which I strongly criticized the Gaia Hypothesis, characterizing it as essentially pseudoscientific, as it is based on a radical misconception, in my mind, of what a living organism is and how evolution works. It is, moreover, entirely untestable empirically. I am not the only critic of Gaia, another one being W. Ford Dootlittle, an evolutionary and molecular biologist, now Professor Emeritus at Dalhousie University in Halifax (Nova Scotia). Ford (we are on a first name basis) has done important work on cyanobacteria, among other things finding convincing evidence that — as predicted by Margulis — chloroplasts, the plant organelles where photosynthesis takes place, originated as endosymbionts.
