The idea of the Earth as an integrated whole, a living being, has a long tradition.
Biologists and Earth scientists usually view the factors that stabilize the characteristics of a period as an undirected emergent property or entelechy of the system; as each individual species pursues its own self-interest, for example, their combined actions may have counterbalancing effects on environmental change. Bunyard, Peter (1996), "Gaia in Action: Science of the Living Earth" (Floris Books), Turney, Jon. [49], Lovelock and other Gaia-supporting scientists, however, did attempt to disprove the claim that the hypothesis is not scientific because it is impossible to test it by controlled experiment. During the 1960s, the first humans in space could see how the Earth looked as a whole. [23] Salinity stability in oceanic environments is important as most cells require a rather constant salinity and do not generally tolerate values above 5%.

[7][further explanation needed] Even so, the Gaia hypothesis continues to attract criticism, and today many scientists consider it to be only weakly supported by, or at odds with, the available evidence.[8][9][10].

Rather than a discussion of the Gaian teleological views, or "types" of Gaia hypotheses, the focus was upon the specific mechanisms by which basic short term homeostasis was maintained within a framework of significant evolutionary long term structural change. Topics related to the hypothesis include how the biosphere and the evolution of organisms affect the stability of global temperature, salinity of seawater, atmospheric oxygen levels, the maintenance of a hydrosphere of liquid water and other environmental variables that affect the habitability of Earth. In 1971 microbiologist Dr. Lynn Margulis joined Lovelock in the effort of fleshing out the initial hypothesis into scientifically proven concepts, contributing her knowledge about how microbes affect the atmosphere and the different layers in the surface of the planet. The Greeks called her Gaia, while the Incas know her as PachaMama. The Gaia hypothesis has since been supported by a number of scientific experiments[44] and provided a number of useful predictions. Among many other speakers: Tyler Volk, Co-director of the Program in Earth and Environmental Science at New York University; Dr. Donald Aitken, Principal of Donald Aitken Associates; Dr. Thomas Lovejoy, President of the Heinz Center for Science, Economics and the Environment; Robert Correll, Senior Fellow, Atmospheric Policy Program, American Meteorological Society and noted environmental ethicist, J. Baird Callicott. Once dead, the living organisms' shells fall to the bottom of the oceans where they generate deposits of chalk and limestone.

How should we be searching for daisies, and should we intensify the search? The temperature will thus converge to the value at which the reproductive rates of the plants are equal. A reduced version of the hypothesis has been called "influential Gaia"[11] in "Directed Evolution of the Biosphere: Biogeochemical Selection or Gaia?" [23] There are many mechanisms that change salinity from a particulate form to a dissolved form and back. The role of selection is to favor organisms that are best adapted to prevailing environmental conditions. The latter is the "weakest" form of Gaia that Lovelock has advocated.

And if we could see this whole, as a whole, through a great period of time, we might perceive not only organs with coordinated functions, but possibly also that process of consumption as replacement which in biology we call metabolism, or growth. Does it matter for Gaia theory whether we find daisies or not? Processing of the greenhouse gas CO2, explained below, plays a critical role in the maintenance of the Earth temperature within the limits of habitability. Less accepted versions of the hypothesis claim that changes in the biosphere are brought about through the coordination of living organisms and maintain those conditions through homeostasis. How can Gaian mechanisms be investigated using process models or global models of the climate system that include the biota and allow for chemical cycling? However, the environment is not a static backdrop for evolution, but is heavily influenced by the presence of living organisms. However, he finds that the two weaker forms of Gaia—Coeveolutionary Gaia and Influential Gaia, which assert that there are close links between the evolution of life and the environment and that biology affects the physical and chemical environment—are both credible, but that it is not useful to use the term "Gaia" in this sense and that those two forms were already accepted and explained by the processes of natural selection and adaptation. Oxygen is a reactive compound, and should eventually combine with gases and minerals of the Earth's atmosphere and crust. In [this] new approach, environmental regulation is a consequence of population dynamics, not Darwinian selection. For example, against the charge that Gaia was teleological, Lovelock and Andrew Watson offered the Daisyworld Model (and its modifications, above) as evidence against most of these criticisms. [18] The hypothesis specifically proposes that particular phytoplankton that produce dimethyl sulfide are responsive to variations in climate forcing, and that these responses lead to a negative feedback loop that acts to stabilise the temperature of the Earth's atmosphere. Recently it was suggested[24] that salinity may also be strongly influenced by seawater circulation through hot basaltic rocks, and emerging as hot water vents on mid-ocean ridges. Currently the increase in human population and the environmental impact of their activities, such as the multiplication of greenhouse gases may cause negative feedbacks in the environment to become positive feedback. [59], Aside from clarifying his language and understanding of what is meant by a life form, Lovelock himself ascribes most of the criticism to a lack of understanding of non-linear mathematics by his critics, and a linearizing form of greedy reductionism in which all events have to be immediately ascribed to specific causes before the fact. Lovelock formulated the Gaia Hypothesis in journal articles in 1972[1] and 1974,[2] followed by a popularizing 1979 book Gaia: A new look at life on Earth. All content on this website, including dictionary, thesaurus, literature, geography, and other reference data is for informational purposes only. The mythical Gaia was the primal Greek goddess personifying the Earth, the Greek version of "Mother Nature" (from Ge = Earth, and Aia =

An article in the New Scientist of February 6, 1975,[41] and a popular book length version of the hypothesis, published in 1979 as The Quest for Gaia, began to attract scientific and critical attention.