From Gaia To Earth Systems Science
Discussion
Adam Frank et al. :
"While Vernadsky thought that ‘cultural biogeochemical energy’ was a minor player in the biosphere until recently, Lynn Margulis had her own conception of the idea and believed it played a larger role in planetary evolution via the Gaia Theory she famously developed along with James Lovelock. The Gaia Hypothesis, as first developed by Lovelock held that Earth's life was able to maintain global conditions, such as average temperature, within a range that kept the planet habitable . Lovelock argued this would occur through negative feedbacks between life and planetary geochemistry. These feedbacks would act to keep perturbations in global conditions in check. What Margulis brought to the collaboration was a focus on the remarkable capacities of microbes to serve as drivers for Gaian feedbacks.
What matters for our concerns is that through her research on evolutionary cooperation (as opposed to competition), Margulis saw the microbial domains as rich with a kind of ‘pre-intelligence’. As she wrote ‘the view of evolution as chronic bloody competition … dissolves before a new view of continual cooperation, strong interaction, and mutual dependence among life forms. Life did not take over the globe by combat, but by networking’ (Margulis and Sagan, Reference Margulis and Sagan1986, p. 122).
Gaia was not, however, to be seen as an organism. As Margulis wrote ‘[Gaia] is an emergent property of interaction among organisms, the spherical planet on which they reside, and an energy source, the Sun’ . This concept of the emergence of a new planetary property from the networked activity of individual players was the central insight of what came to be called Gaia Theory. As Margulis later wrote ‘Gaia is the regulated surface of the planet incessantly creating new environments and new organisms…. Less a single live entity than a huge set of interacting ecosystems, the Earth as Gaian regulatory physiology transcends all individual organisms’ (Margulis and Sagan, Reference Margulis and Sagan1986, p. 120).
Gaia Theory was controversial when it was first proposed, particularly because some saw it as introducing a teleological principle into evolution (Dawkins, Reference Dawkins1982), while others argued that there was no means for it to arise through natural selection (Doolittle, Reference Doolittle2017). We note that there still remain questions concerning the evolution and efficacy of biospheric feedbacks for producing a full planetary homeostasis (Kirchner, Reference Kirchner2002). Recent work, however, points to evolutionary mechanisms that may select for the global-scale negative feedbacks which could maintain such a system (Lenton et al., Reference Lenton, Daines, Dyke, Nicholson, Wilkinson and Williams2018).
Still, the basic principles of Gaia Theory, effectively repackaged as ‘Earth Systems Science’, now represent the cornerstone of modern approaches to Earth's evolutionary history. What Earth Systems Science took from Gaia Theory was its recognition of the biosphere as a principal driver of planetary evolution, as well as the profound role of collective microbial activity in shaping critical biospheric feedbacks."