Volk, Tyler. 1998. Gaia's Body: Towards a Physiology of Earth. Copernicus, Springer-Verlag, New York ISBN 0-387-98270-1, 269 pp, $--.--.
"I am a voyager inside the biosphere." So states the author in his Preface. "All of us are cells within the embracing physiology of what Jim Lovelock has called 'Gaia'." This is news to many students; the Earth is a physiological system. "Organisms evolved. Gaia did not." This goes with a belief: Earth is alive, it self regulates, and is a self-sustaining organism (or perhaps a quasi-organism). The author follows the work of Lovelock and Lynn Margulis. He considers Gaia to be: "...the interacting system of life, soil, atmosphere, and ocean." It is molecules within cells ... life ... complex cycles ... material transformations driven by biological energy ... within the whole Gaian system itself. "Although Gaia has changed through time, it does evolve in a Darwinian sense." This is the science of "geophysiology."
In Chapter 1. "Breathing of the Biosphere," we should expect to read about the "feedback loops of influence that control of the cycles of matter." Chapter 2. "A Global Holarchy, develops some conceptual underpinnings for treating Gaia as a whole made up of parts." In Chapter 3. " Outer Light, Inner Fire," solar energy and core heat drive the atmosphere and oceans. Chapter 4.(discusses) "The (four) Parts of Gaia," described above. Chapter 5."Worldwide Metabolism," is an inward probing discussion. Chapter 6. "Embodied Energy," drives (bio)chemical transformations. Chapter 7. "The Music of This Sphere," is about biological cycles. Chapter 8. "Gaia in Time," lays the storyline for the emergence of biology within the larger system. The Bibliography lists 13 general references and 98 specific references for each chapter. The Index is seven pages.
The book is easy to read; hard for me to accept. Its like --the photosynthesis of a lake! An easy concept for some who make a measurement of the processes of the many that yield oxygen and consume carbon dioxide, change pH, and who cares what else. Thinking "global" or "system" is easy for some---hard for others. I know many ecologists who can do this without thinking Gaia (Global Ecology). Greenhouse gas! Heat. The carbon cycle. The nitrogen cycle. Oxygen. Sulfur. Air and water currents. Weather. Hydrothermal systems. Margulis' five kingdoms. Woese and Domains! Phylogeny! Archaea everywhere.
H. Morowitz's view of life are discussed (page106 -107): Energy Flow in Biology, 1979, Ox Bow Press, Woodbridge, CT; and, Beginnings of Cellular Life, Yale University Press, New Haven, CT. He generalizes the "universal lipid membrane." But it isn't a lipid membrane. It is the fluid mosaic model for the membrane in which lipids are one part. The author states that these are generalizations ---about the "ancestry from which all life stems." If the first cells are of his type, o.k.,; they may have lipid membranes that evolve. But, if the first cells are self-assembled from moistened thermal proteins (Thermal Protein-First Paradigm for the origin and early evolution of life), the lipid concept must be set aside.
Life is life. It isn't soil, atmosphere, or ocean (page 123). But what is it? (Jump to page 224.) Did it come from space (in the pores of meteorites)? Did it originate deep within the Earth? Is it still there? Did it form upon clay particles? Well, evidence of it exists (microfossils). Imagine ... "3.5 billion years ago, a few hundred million years after the origin of life." ... Imagine an average Earth surface temperature at about 40 - 50 degrees centigrade (compared to today's average of 15 degrees centigrade). The Earth days were only 14 hours long (faster spinning rate). The Moon was closer to Earth. But, the onset of life is difficult to reconstruct.
Euan Nisbet (University if London) proposes that life began in hydrothermal vents. He claims the first organisms were prokaryotic ancestors of both bacteria and archaea. (Page 225.) These could occur along ridges on the ocean floor or near volcanoes (flanks) with hydrothermal flows. Both areas are rich in minerals (nitrogen, iron, sulfur, copper, manganese, and magnesium. Complex carbon-containing compounds would be there, such as an "ancient chlorophyll similar to ... bacteriochlorophylls, which absorb in the infrared, ..."This solar energy would be used to "split water." This would liberate early life from dependence on chemosynthesis in hydrothermal systems (page 226) and enabled them to live in shallow lagoons and bays or float on the seas. But this is beyond the origin of life. This is the early evolution of life! Released oxygen would react quickly with other chemicals reducing its concentration. Two billion years ago, oxygen began to accumulate in the atmosphere (from a trace up to about one-sixth of the present level: see page 228, Dick Holland). First eukaryotic cells appeared (amoebae; diatoms; etc.). Volcanoes decreased their release of gases that reacted with oxygen, enabling it to rapidly accumulate (James Kasting, see page 229). Carbon was being buried at that time, and it happened again between 1,000,000,000 and about 600,000,000 years ago.(See page 229; Donald Canfield and Andreas Teske.) The rest of the story is given. A careful reading is encouraged.
This book was reviewed by Aristotel Pappelis ( Professor, Department of Plant Biology, Southern Illinois University at Carbondale, Carbondale, IL 62901)