III. Ecosmos: A Revolutionary Fertile, Habitable, Solar-Bioplanet, Incubator Lifescape

3. Earth Alive: An Ovular GaiaSphere Sustains Her/His Own Viability

Lin, Guangxing and Zuntao Fu. A Universal Model to Characterize Different Multi-Fractal Behaviors of Daily Temperature Records over China. Physica A. 387/573, 2008. Peking University physicists quantify that even atmospheric phenomena can be found to exhibit a power-law scale similarity. As an analog, we add that ocean temperature gradients also hold to such mathematics, which then influence fish schools to do the same.

Lovelock, James. Gaia: A New Look at Life on Earth. New York: Oxford University Press, 1979. The original work by a British atmospheric chemist who initiated the modern conception of the planet as a self-sustaining entity.

Lovelock, James. Healing Gaia. New York: Harmony Books, 1991. An illustrated exposition of a “planetary medicine” which is now imperative to cope with the perilous human impact on earth’s life support systems.

Lovelock, James. The Living Earth. Nature. 426/769, 2003. A recent summary of the Gaia hypothesis whereby organisms and their environment co-evolve so as to maintain the biosphere as a single, self-regulating system.

Luhr, James, editor-in-chief. Earth. New York: DK Publishing, 2003. This profusely illustrated encyclopedia is a great resource for the evolution, structure, dynamics and composition of our home planet in its cosmic setting.

Lyons, Timothy, et al. Oxygenation, Life and the Planetary System during Earth’s Middle History. Astrobiology. July 21, 2021. Six geoscientists from UC Riverside, Yale, China University of Geosciences and Georgia Tech advance understandings of how our habitable, self-sustaining bioworld could to exhibit some manner of an inherent biological development, maybe along a course to our retrospective.

The long history of life on Earth has unfolded as a cause-and-effect relationship with the evolving amount of oxygen in the oceans and atmosphere. An oxygen deficiency held over the first 2 billion years, yet evidence for biological O2 and local ocean enrichments appear before O2 in the atmosphere some 2.3 billion years ago. However, the relationship between complex life (eukaryotes, including animals) and later oxygenation is less clear. The apparent rise in O2 around 800 million years ago is coincident with major developments in complex life. This paper focuses on the geochemical records of Earth's middle history, roughly 1.8 to 0.5 billion years ago, so to explore an interactivity with biological evolution. A richer understanding of the interplay between coevolving life and Earth surface environments can provide a template for studies of sustained habitability on distant exoplanets. (Abstract excerpt)

Margulis, Lynn. Symbiotic Planet: A New Look at Evolution. Reading, MA: Perseus Books, 2000. The biological process of symbiosis, especially in the bacterial realm, serves the maintenance of an organically unified biosphere.

The sum of planetary life, Gaia, displays a physiology that we recognize as environmental regulation. Gaia itself is not an organism directly selected among many. It is an emergent property of interaction among organisms, the spherical planet on which they reside, and an energy source the sun. (119)

Margulis, Lynn, et al, eds. Environmental Evolution. Cambridge: MIT Press, 2000. A survey of atmospheric, biological, and geological conditions from their Archean origins to the industrial revolution and its consequences.

Maruyama, Shigenori and Toshikazu Ebisuzaki. Origin of the Earth: A Proposal of New Model called ABEL. Geoscience Frontiers. 8/253, 2017. In this online journal from the China University of Geosciences, in a Frontiers in Early Earth History and Primordial Life issue, Earth-Life Science Institute, and RIKEN Computational Astrophysics, Japan researchers consider at length with graphic displays, via a novel theory ABEL: Advent of Bio-Elements Bombardment, how our home planet might have come to be a habitable abode for metabolic evolution. A primal phase of biochemical arrivals is later seen to promote conducive plate tectonics. See also Tandem Planet Formation for Solar System-like Planetary Systems and Subduction of the Primordial Crust into the Deep Mantle.

Mussini, Giovanni and Frances Dunn.. Decline and fall of the Ediacarans: late-Neoproterozoic extinctions and the rise of the modern biosphere.. Biological Reviews. 99/1, 2024. Cambridge and Oxford University natural historians provide a latest retrospective on life’s epochal transformation from rudimentary stages through to distinct organisms on their evolutionary way. But as increasingly evident, this emergent event involved safe passage through a narrow, hazardous zone of viability. As one reads the text below, an impression may be gained that some manner of developmental scale was trying to proceed by its own persistent self.

The end-Neoproterozoic transition marked a gradual shift between distinct configurations of Earth's biosphere. This interval saw the demise of the enigmatic Ediacaran Biota and ushered in trophic webs and animal body plans of Phanerozoic ecosystems. However, little consensus exists on its reality, drivers, and macroevolutionary implications. Here we consider recent findings on Ediacaran geochronology, the persistence of macrobionts into the Cambrian, and the crown-group eumetazoans. We argue that the protracted effects of novel bilaterians may best account for the structure and selectivity of late-Neoproterozoic extinctions.. Given resource distribution in Ediacaran ecologies, and continuities among Ediacaran and Cambrian faunas, we suggest that the rise of Phanerozoic-type biotas may have been unstoppable.

The “destructive creation” accompanying the diversification of crown-group eumetazoans and decline of the Ediacaran Biota finds no true parallels in the subsequent 539 million years. The Ediacaran hourglass neck was a macroevolutionary revolution which terra-formed marine ecosystems past irreversible tipping points. (5)

The implications of end-Neoproterozoic extinction dynamics are far-reaching. Instead of representing historical accidents, the fall of the Ediacarans and the emergence of Phanerozoic ecologies hint at a key role for endogenous, self-sustaining eco-evolutionary cascades in shaping the history of the biosphere. (16)

The Ediacaran period is a geological period of the Neoproterozoic era that spans 96 million years from the end of the Cryogenian period at 635 Mya, to the beginning of the Cambrian period at 538.8 Mya. The subsequent Cambrian period marks the start of the Phanerozoic eon where recognizable fossil evidence of life becomes common.

Nicholson, Arwen, et al. Alternative Mechanisms for Gaia. Journal of Theoretical Biology. Online August, 2018. As discussions and arguments ever persist about an evolutionary self-regulation of biospheric viability, University of Exeter Earth system scientists including Timothy Lenton, along with University of Lincoln life scientist David Wilkinson finesse a way that selective effects on a global scale may be seen to serve life’s evident long term stable presence. See also Is Gaia Alive? The Future of a Symbiotic Planet by Roberto Cazzolla Gatti in Futures (Online August 2018).

A long-standing objection to the Gaia hypothesis has been a perceived lack of plausible mechanisms by which life on Earth could come to regulate its abiotic environment. A null hypothesis is survival by pure chance, by which any appearance and persistence of regulation on Earth is illusory. Recent work, however, has proposed that persistence alone empowers a biosphere to acquire further persistence-enhancing properties. Here we use a simple quantitative model to show that such ‘selection by survival alone’ can indeed increase the probability that a biosphere will live on in the future, relative to a baseline of pure chance. Adding environmental feedback to this model shows either an increased or decreased survival probability depending on the initial conditions. The outstanding question remains the relative importance of each mechanism for the historical and continued persistence of life on Earth. (Abstract)

Nicholson, Arwen, et al. Gaian Bottlenecks and Planetary Habitability Maintained by Evolving Model Biospheres: The ExoGaia Model. arXiv:1803.08063. Earth systems scientists Nicholson, Hywel Williams, and Timothy Lenton, University of Exeter, and David Wilkinson University of Lincoln, UK who study globally organic processes at work (search Lenton) expand this approach as an effective way to detect life-bearing exoworlds. See also The Case for a Gaian Bottleneck: The Biology of Habitability by Aditya Chopra and Charles Lineweaver herein, along with Earth: Atmospheric Evolution of a Habitable Planet by Stephanie Olson, et al at arXiv:1803.05967 for similar reviews. For a later verification see Typical Climate Perturbations Unlikely to Disrupt Gaia Hypothesis by Olivia Alcabes, et al. at arXiv:1906.01112 which finds that astrogeological impacts would likely not disrupt this long term bioregulation process.

Planet habitability models traditionally focus on abiotic processes and neglect a biotic response to changing conditions on an inhabited planet. The Gaia hypothesis postulates that life influences the Earth's feedback mechanisms to form a self-regulating system, and hence that life can maintain habitable conditions on its host planet. We present the ExoGaia model - a model of simple 'planets' host to evolving microbial biospheres. Model planets orbit a 'star' which provides incoming radiation, and atmospheric chemicals have either an albedo, or a heat-trapping property. Planetary temperatures can therefore be altered by microbes via their metabolisms. We find five distinct classes of model planets, including clear examples of 'Gaian bottlenecks' - a phenomenon whereby life either rapidly goes extinct leaving an inhospitable planet, or survives indefinitely maintaining planetary habitability. These results suggest that life might play a crucial role in determining the long-term habitability of planets. (Abstract excerpts)

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