About the SA Blog Network

History of Geology

History of Geology

What rocks tell and how we came to understand it
History of Geology Home

Mother Earth

Email   PrintPrint

Fig.1. “Mother Earth”,  the nourisher of all things, from the alchemistic work “Atalanta fugiens” (1618) by Michael Maier (image in public domain).

Surface conditions on Earth, have been for most of geological time regulated by life…[]…This new link between Geology and Biology originated in the Gaia hypothesis
NASA geologist Paul Lowman (2002)

In 1965 James Lovelock, inspired by research on the habitability of Mars, proposed in a Nature-article to consider the various spheres of earth (lithosphere, hydrosphere, biosphere and atmosphere) as an interconnected, self-regulating system. He followed the suggestions by novelist William Golding and named this idea the controversial Gaia-hypothesis, after the ancient  titan Gaia – the personification of earth.
Lovelock argued that biotic and abiotic processes limit the possible amplitude of changes of terrestrial conditions – like the salinity of the oceans, the surface temperature and the atmospheric chemistry – therefore forcing earth into a life-supporting disequilibrium between two stable extremes, the frozen wasteland of Mars and a greenhouse hell of Venus.
In 1971 microbiologist Lynn Margulis (1938-2011) joined Lovelock (here an interview with both scientists in 2011), emphasizing the link between geology and biology for the Gaia-hypothesis.

Some 30 million types of extant organisms have descended with modification from common ancestors; that is, all have evolved. All of them-ultimately bacteria or products of symbioses of bacteria – produce reactive gases to and remove them from the atmosphere, the soil, and the fresh and saline waters. All directly or indirectly interact with each other and with the chemical constituents of their environment, including organic compounds, metal ions, salts, gases, and water. Taken together, the flora, fauna, and the microbiota (microbial biomass), confined to the lower troposphere and the upper lithosphere, is called the biota. The metabolism, growth, and multiple interactions of the biota modulate the temperature, acidity-alkalinity, and, with respect to chemically reactive gases, atmospheric composition at the Earth’s surface.

However the general notion that the Gaia-hypothesis states that “earth as a living planet” or a “life form” in the sense of entity is incorrect.
Organism do not manipulate deliberately the system so it can support them; however if an organisms harms his environment (and the life-supporting properties) it eventually will be naturally selected from the system. Fortunately environments can also tolerate some degree of change without losing their life-supporting properties.

The legacy of the Gaia-hypothesis is the consideration to see geology as one of the Earth System Sciences and appropriately to consider what we call “Earth” as the result of “elegant truths; of exquisite interrelationships; of the awesome machinery of nature.” (Carl Sagan in episode 1 of Cosmos “The Shores of the Cosmic Ocean”, 1990)


MARGULIS, L. (2004): Gaia by Any Other Name. In (ed.), Schneider S.H.: “Scientists Debate Gaia – The Next Century”: 7 – 12

David Bressan About the Author: Freelance geologist dealing with quaternary outcrops interested in the history and the development of geological concepts through time. Follow on Twitter @David_Bressan.

The views expressed are those of the author and are not necessarily those of Scientific American.

Rights & Permissions

Comments 2 Comments

Add Comment
  1. 1. M Tucker 5:17 pm 04/22/2013

    When you say, “Organism do not manipulate deliberately the system so it can support them” I think of beavers. What are they doing? Aren’t they deliberately manipulating the environment?

    “however if an organisms harms his environment (and the life-supporting properties) it eventually will be naturally selected from the system.” Sure, that makes sense. But what about the 5 famous large extinction evens? Sure a couple might have an extraterrestrial origin but surely not all. Did those extinct species harm their environment?

    I agree the Gaia hypothesis is a naively oversimplified proposition.

    Link to this
  2. 2. jgrosay 5:25 pm 04/25/2013

    I’d say ‘mother’ Earth’, ‘Pachamama’, ‘Gea’, ‘Ceres’, ‘Demeter’, are all different names for the same devil, it’s good paying attention to the hidden links in names and words…

    Link to this

Add a Comment
You must sign in or register as a member to submit a comment.

More from Scientific American

Scientific American MIND iPad

Give a Gift & Get a Gift - Free!

Give a 1 year subscription as low as $14.99

Subscribe Now >>


Email this Article