The Gaia Hypothesis

The Gaia hypothesis proposes that living and nonliving parts of our planet interact in a complex network like a superorganism. Named after the Greek earth goddess, the hypothesis postulates that all living things exert a regulatory effect on the Earth’s environment that promotes life overall.

First formulated in the 1960s during his work for NASA on methods of detecting life on Mars, Dr. James Lovelock named this self-regulating living system the Gaia Hypothesis after the Greek goddess, using the suggestion of novelist William Golding, who lived in the same village as Lovelock at the time. According to Lovelock, Gaia is:

A complex entity involving the Earth’s biosphere, atmosphere, oceans, and soil; the totality constituting a feedback or cybernetic system which seeks an optimal physical and chemical environment for life on this planet.

Lovelock’s arguments included:

1) constancy of global surface temperature, despite increase in the energy provided by the sun; constancy of atmospheric composition, even though it should be unstable; and

2) constancy of ocean salinity.

Lovelock published the Gaia Hypothesis in journal articles along with co-author Dr. Lynn Margulis using two fundamental components:

· The planet is a “super organismic system” (Margulis)
· Evolution is the result of cooperative not competitive processes.

Unlike Lovelock’s rather flamboyant language, Margulis’s stable intonations reflect an insight into the subtle logic and fractal self-organization of Nature. According to Margulis, biospheres have no special tendency to preserve their current inhabitants, or make them comfortable. Accordingly, Earth is not a living organism which can live or die all at once, but a community of trust, which can exist at many discrete levels of integration, what she referred to as “an emergent property of interaction among organisms.” However, she also argued that “the surface of the planet behaves as a physiological system in certain limited ways” and the earth’s surface is “best regarded as alive.”

Because the hypothesis has since been supported by a number of scientific experiments and has provided a number of useful predictions, it is now referred to as the Gaia Theory. However, the theory remains accused of being teleological by critics within the scientific community, including Richard Dawkins and Ford Doolittle. Dawkins rejected the possibility of feedback loops: “there was no way for evolution by natural selection to lead to altruism on a Global scale.” Other scientists rejected the implication of a “living” Gaia, unable to reproduce. However, if all this is viewed less literally and more metaphorically, then the remark from astronomer Carl Sagan both surprises and illuminates: he observed that from a cosmic viewpoint, the space probes since 1959 have the character of a planet preparing to go to seed.

Margulis’s Theory of Endosymbiosis (see my previous post):

Lynn Margulis contended that symbiosis, not chance mutation, was the driving force behind evolution and that the cooperation between organisms and the environment are the chief agents of natural selection—not competition among individuals. In her 1981 book, “Symbiosis in Cell Evolution” Margulis proposed that the ancestors of eukaryote cells were symbiotic consortiums of prokaryote cells with one or more species (endosymbionts) being involved. The progenitor of the mitochondria or chloroplast supposedly gained entry into the host prokaryote as undigested prey or as an internal parasite after which the arrangement became mutually beneficial to both partners (the ‘host’ cell and the endosymbiont) and the prokaryotes continued to live on as organelles within the new type of cell. An obligatory symbiosis evolved as they became more interdependent.

“Gaia is just symbiosis as seen from space,” one of Margulis’s students was said to have remarked.


Recommended Reading:

Lovelock, J.E. 1972. Gaia as seen through the atmosphere. Atmospheric Environment, Elsevier Science 6: 579-80.
Lovelock, J.E. and L. Margulis. 1974. Atmospheric homeostasis by and for the biosphere: the gaia hypothesis. Tellus: a bimonthly journal of Geophysics, Swedish Geophysical Society 26(1): 2-10.
Lovelock, James. 1979 (2000). Gaia: A New Look at Life on Earth. 3rd Edition. Oxford University Press.
Lovelock, James. 1988 (1995). Ages of Gaia. Oxford University Press.
Margulis, Lynn. 1981. Symbiosis in Cell Evolution. W.H. Freeman & Company. 419pp.
Margulis, L. 1998. Symbiotic Planet: a New Look at Evolution. Weidenfeld & Nicolson. London.
Volk, Tyler. 2003. Gaia’s Body: Toward a Physiology of Earth. MIT Press.

Nina Munteanu is an ecologist and internationally published author of novels, short stories and essays. She coaches writers and teaches writing at George Brown College and the University of Toronto. For more about Nina’s coaching & workshops visit www.ninamunteanu.me. Visit www.ninamunteanu.ca for more about her writing.