Thursday, October 13, 2016

Book Review: A New History of Life

Peter ward and Joe Kirschvink: A New History of Life, Bloomsbury Press (New York), 2015: 356 pages, extensive chapter notes, index, graphs, diagrams, photos, sketches - well illustrated.












             


          



 Peter Ward




Abbreviations used:
 
CC - climate change
CO2 - carbon dioxide, a potent greenhouse gas
GHG - greenhouse gas (responsable for global warming and climate change)
GW - global warming
mya - million years ago


  Joe Kirschvink

"With every molecule of carbon dioxide we pump into the atmosphere we are ignoring the early warning sirens that rapid rises in carbon dioxide are the commonality between more than ten mass extinctions of the deep past and what is happening today. Those extinctions were caused not by asteroid impact, but from rapid increases in volcanically produced atmospheric greenhouse gases and the global warming they produced. A terrifying new paradigm of mass extinction has arisen this century: "greenhouse mass extinctions", a name overtly chosen to describe the cause of the vast majority of species killed off by mass extinctions in the past." (page 3)

"The increasing acceptance of the dominant roles of oxygen and carbon dioxide levels in understanding not only large-scale patterns but nuances of life's progression on our planet is in many respects a twenty-first century innovation in interpreting Earth history. As is the understanding that two other important gases have played dominant roles in the story of life, and in the pages to come: hydrogen sulfide and methane. Their stories are written in rock, life, and death as well." (page 27)

"Over and over, however, it really looks like a dominant theme in the history of life is that times of crisis promote new innovation. Diversity stays low, but disparity - the measure of the number of different, an in the dinosaur's case, radically different body plans and anatomies - skyrockets. An analogy comes from Tom Wolfe's wonderful book The Right Stuff. In it he describes the often short and violent ends of test pilots in the late 1950s, when giant new jet planes were being developed. Sooner or later any test pilot would find himself in a death dive. But Wolfe describes the reactions of the pilots: very cooly going through the progressions - trying method A, no, try B, try C... In the latest Triassic world, so many organisms were those crashing jets, with evolution as the pilot, trying this morphology, then another, then another. To use this analogy, it was dinosaurs that pulled out of the death spiral that the low-oxygen, late Triassic biosphere had become by evolving the most sophisticated and efficient set of lungs that the world has ever seen." (page 247-8)
          Necessity is the Mother of Invention!




  Hynerpeton: Devonian age proto-tetrapod ("4 legged", all modern terrestrial vertebrates are tetrapods). It lived 360 mya. A "transitional" form with both lungs and gills 

              I read this book for two reasons. Firstly, I am interested in Self-Organizing Systems and biological evolution is the prime example of Self Organization at work. Life began with proto-organic molecules self-organizing as a result of a flux of energy through the medium (sea water) which housed them. New History, as the title indicates, is a synthesis of contemporary discoveries, dating back to improved fossil dating technology (non-radioactive isotopic analysis developed in the 1960s) and culminating in the first decade of the new millennium with a deeper understanding of the physical drivers of evolution and mass extinctions.

              Profs Ward and Kirschvink are major contributors to the emerging "New Synthesis" (yet unamed) which perceives life as an emerging Self Organizing phenomenon. They are pioneers in advancing our understanding of the interactions between life and the physics and chemistry of the planet (particularly atmospheric chemistry and physics). They have made major contributions  in the dating of the Permo-Triassic boundary (Late Permian Mass Extinction) and elucidating the structure, duration and nature of its successive exterminatory pulses.  


 Ichthyostega: Devonian age amphibian, an inhabitant of the extensive marine mangrove forests of the time. Ichthyostega was an aquatic predator but was able to traverse short streches of land either to feed on giant insects or to change swamps.

              My second reason for reading New History is to provide myself with intellectual arms against CC deniers. For my own peace of mind, I to bury any niggling doubts remaining about the reality and seriousness of CC / GW. I want to finish this "debate" so I can move on to more pressing issues demanding my attention (note 1) 

          Perhaps more importantly, I want to prepare myself to offer people, especially younger people (at my age, anyone less than 50..), a fact-based understanding of the relation between living organisms, including humans, and the physical environment we share. "Normal", "traditional" regional climates are rapidly shifting, dislocating, re-organizing. Many people will soon wake to this new reality, to the new normal. In fact, due to the increasingly wacky weather, many people are awakening but a tipping point in public consciousness has not been reached in most countries. National governments do indeed make appropriate noises but outside of Scandinavia, Germany, Scotland and more recently, China, efforts to make the transition to a green economy are more words than action. And, even in the above mentioned countries, the actions taken are, by my standards, still somewhat "anemic".

            I want to be pro-active, I want to have facts at my disposal (and useful skills, practical knowledge for the hard days coming). Unnatural "natural" disasters are beginning to waken "the masses" from their consumer culture induced hypnosis. Among those awakening from deep denial, there will be many who remain stunned, confused, disoriented. Providing them with a realistic Roadmap of our New Reality may, I hope, help them to take sane, realistic, corrective actions. 

           I concede that it is late, very late. We have waited far too long to launch the transition from a fossil fuel to a renewable energy economy. There will be heavy costs to pay for our continued inaction. At this late date, we may not be able to save the house but, with luck, we may be able to save some furniture and valuables. We may lose a lot but we are not lost (yet..) To further delay action - given what I now know about the risks implied by CC / GW - would be simply immoral.

         Building "Cultural Refugia" is my current priority. "Debating" the scientific - or other - "reality" of CC simply wastes precious time and energy. In a sense, I read New History to help me turn this page and get on with something new.

         On a purely intellectual level, New History is a fascinating read on its own merits. I confess that Prof Ward is not my favorite science writer: sloppy proof reading leaves too many typos, syntaxically challenged and ambiguous sentences. On occasion, a desire to communicate to a general readership leads to oversimplication or incomplete arguements thereby vitiating the very arguments he is trying to present. However, New History's obvious importance as a major work of popular scientific synthesis - in a politically important and rapidly evolving area of study - far outweigh such "stylistic" quibbles.

         Given the importance of GHG emissions to CC, New History's appearance is timely on several fronts. It represents an emerging holistic view of the co-evolution of life and its environment. Darwin, of course, noted such interactions and correctly called attention to their importance in understanding the Saga of Life on earth.

         However, it took another 100 years, to the 1960s, for science to develop the tools, physical and conceptual, to explore the details of ecosystem / environment interaction through Deep Time, the billions of years life has existed on earth. The original "breakthroughs" (more evident as such in retrospect) were the development of measures which record past biological activity and the climate conditions they took place under. For example, the comparison of the ratios of non-radioactive isotopes of biologically active elements in fossils like oxygen, carbon, sulfur.. Because these isotopes are not subject to radioactive decay, they lock into the fossil record valuable indices of organism / environment interaction.

         Biological processes favor isotopically light elements. Carbon 12 (6 protons, 6 neutrons in nucleus) is absorbed a wee bit faster than C 13 (7 neutrons) or C 14 (8 neutrons). Variations in the relative amounts of different isotopes of biologically active elements (carbon, oxygen, sulfur..) found in rocks can provide valuable clues to the first appearance of life, its origin, intensity and disappearance.

          Building on the successes of non-radioactive isotopic paleontological studies, a deepening knowledge of the nature, sequence and duration of major evolutionary events has emerged over the past 50 years. In the first decades of the new millennium, these discoveries have sparked a "new synthesis", a marvellously rich, detailed and profound understanding of life's emergence and its unfolding interaction with the physical environments of one small planet of an insignificant star in an insignificant galaxy. The subject matter of New History is this New Science of Life: the title was well chosen.

           It is perhaps on a deeper, "philosophical" level that the New Science of Life will have its greatest, long term impacts.

          Life, as now understood, has four major requirements:

1- A flow of energy of sufficient strength and constancy. On earth this energy flow arrives from the sun as radiant energy, largely as visible light

2- An appropriate solvent for biochemical reactions to take place in. Dissolving biochemical reactants in a solvent increases the probability that two reactant molecules will encounter each other, rendering chemical reaction possible. The solvent must also be present in sufficient quantities in liquid form under ambient planetary conditions for life to emerge and flourish. On earth the universal biosolvent is water. It is postulated that life might flourish in saturated water / ammonia solutions which freeze well below the freezing point of water. These solutions occur in abundance on the outer planets and moons of our own solar system. Other solvents for low temperature biology have been proposed: liquid ammonia, liquid nitrogen. Their potential biochemistries are highly speculative at the present state of knowledge. 


                          Titan, a moon of Saturn rich in low temperature proto-organic
chemistry (and exotic life?) 

3- Chemical cycling. Chemical cycling occurs when the products of a chemical reaction are also its inputs. This means that, given an adequate energy flow (point 1 above), and an adequate supply of raw materials (point 2 - biosolvent), the reaction has the potential of self-maintenance. This is the first step toward the capacity to reproduce individual organisms. Chemical cycling has been observed in the atmosphere of the low temperature moon of Saturn, Titan.

            Biologically driven chemical cycling on earth creates huge stores of energy storing, energy releasing or otherwise biologically useful chemicals. Such substances are considered "biosignatures" or "biomarkers" in the search for extra-terrestrial life since the presence of life maintains their abundance at levels which are extremely far from chemical equilibrium. On earth, the photosynthesis of plants maintains the level of (extremely reactive!) oxygen at levels impossible on a dead world. Oxygen is used by living organisms to release biologically useful energy by oxidizing energy rich hydrocarbons (sugars, starches, fats..) in the slow burn of metabolism. Methane levels are way out of chemical equilibrium on Titan - are there Titanian microbes burning acetylene into methane to obtain life energy?

                              The cycling of carbon by earth life (click to enlarge image)

4- Polymeric chemistry. In polymeric reactions, repetitive "base units" are strung together like links in a chain. This creates the possibility of storing information - a "message" or "code" - by adding slight variations to each link of the chain. DNA and RNA molecules are used by life on earth to encode the "blueprints" or "recipes" used to synthesize essential biochemicals like proteins. DNA also contains the whole body code that allows organisms to produce offspring similar to themselves, thus living species persist over time, transcending the death of individuals. Copying procedures are never perfect, however, allowing random mutations to occur in the genetic code when DNA molecules are copied. Such mutations provide the raw material of evolution: since mutated organisms are different than the "standard model", natural selection will favor the propagation of the mutants best adapted to the environment they live in.


 
           In 1979, physical chemist and inventor, James Lovelock coined the term "Gaia hypothesis" for a new way of defining and looking at life. Lovelock was working on a contract with NASA to devise ways of detecting life on other planets. He came up with the idea of searching for spectroscopic signals of "biosignature" molecules (point 3 above). A telescope - on earth or in space - would search for the frequencies of light (or infrared - heat) energy given off or absorbed by biologically important molecules in the atmospheres of distant planets. For example, In the earth's upper atmosphere, diatomic - two atom - oxygen molecules are broken down and re-assembled by ultraviolet rays into triatomic ozone molecules. This reaction is marked by a strong absorption line in light passing through the earth's atmosphere. This line is considered a potential "biomarker" for future exoplanet life detection missions by NASA.


               Lovelock's work with NASA led him to consider the totality of life on earth as a sort of "planetary super-organism", hence the name Gaia Hypothesis: Gaia was the archaic Earth Mother of the ancient Greeks. The beauty of the hypothesis lies in its recognition that life is an emergent phenomenon, rising from the interactions between life and the physical body of the earth: oceans, atmosphere, soils, the rocky substrate, glaciers and polar ice caps. In some ways, the Gaia Hypothesis, appearing in the mid-twentieth century, can be compared to Darwin's theory of Natural Selection which appeared in mid-nineteenth century. Both theories culminated and synthesized a period of scientific discoveries about the nature of life which could not easily be incorporated into the dominant world view of the times. In Darwin's case, the picture of life evolving new species over Deep Time "collided" - called into question - the traditional Christian theological view that God created all species at the same time, some 6000 years ago in the Near Past. The Gaia Hypothesis sees all life, including humans, as an emergent, co-evolving, self-regulating system maintaining itself in a "bio-geo-chemical" milieu through delicately balanced, mutual interactions with that environment. This world view collides with the dominant anthropocentric worldview which sees humanity "above" Nature, its "master" who freely exploits "natural wealth" for the "profit" of our species. Our imploding ecology (the Sixth Mass Extinction - note 2) and deregulated climate give the lie to this ideological fallacy, of course..

          Lovelock's hypothesis found a natural resonance with ecological movements and back-to-nature enthusiasts. It's "scientific" dimensions were muted and it became romanticized as a modern image of Mother Nature. (I'm not negating the validity - or necessity - of these interpretations. I'm just making an observation..)  Scientifically, though, as all good scientific hypotheses must, the Gaia Hypothesis became the subject of professional scrutiny and criticism. Unlike Darwin's Natural Selection which has proven resilient over time, adapting itself to the rigors of creative criticism, the fate of the Gaia Hypothesis (like the earth itself!) is still unclear.

             New History, although it never mentions the Gaia Hypothesis directly, discusses some its flaws (and some additional flaws generated by non-scientific enthusiasts). Gaian enthusiasts often laud the "balance" of nature. Some speak of Gaia having meaning, purpose and plans (again, I don't deny such ideas: they are simply not part of the scientific Hypothesis elaborated by Lovelock. Lovelock, in fact, explicitly denies meaning, consciousness or goals to Gaia. Note 3). New History correctly points out that life, while opportunistic and struggling to survive and flourish:

1- Only has a limited regulatory power over biogeochemical processes. Lovelock, in some writings, has claimed that all aspects of the chemical milieu we live in are regulated by life. This is true, in a sense, but it does not mean that "Gaia's" control is arbitrary or total. Carbon dioxide and oxygen levels of the atmosphere are linked processes so cannot be arbitrarily adjusted as Gaia might like, nor can they be manipulated with impunity. Too much oxygen results in massive forest fires which kill off trees reducing photosynthetic oxygen production, thereby lowering percentage oxygen content of the atmosphere to sustainable limits. Gaia has limits..

2- Gaia can also act, blindly, against Her own self interests. Early photosynthetic microbes drew down massive quantities of CO2 from the primitive atmosphere which was extremely rich in the gas by modern standards. Since the early sun was cooler than the sun of today, the drop in CO2 - a greenhouse gas - caused the earth to cool off - and freeze. The earth went through several such "snowball earth" phases several billions of years ago. The seas froze solid, except perhaps for an equatorial "slush belt" where some marginal photosynthetic activity could take place. Life never went extinct but became quiescent. Over time, volcanic activity would raise global CO2 levels, the earth would thaw out and microbial life would bloom again: absorbing CO2 and releasing oxygen in industrial quantities till the temperature fell, provoking another universal snowball earth, lasting a hundred million years or so.

            There is much food for thought in this book. The main message for me is that life is an emerging, self-complexifying process in tight interaction with its physical milieu upon which it depends, that healthy life modifies its environment so it can flourish and that this control is, at best, very partial. New History is a good read and, as I wrote earlier, one of the best popular syntheses of the New Science of Life available for the non-specialist reader. 

notes:

1- To simplify an argument, a bit. It is today probably too late to make the transition to a green (post fossil fuel) economy without "major disruptions": 

- rolling regional crop failures due to CC and disruption of the traditional weather patterns around which traditional agricultures were built: the Asian monsoons, for example, 

- mass human die-off, exterminatory warfare, 

- cultural regression.. 

Basically, I want to devote myself to preserving the best that 8000 (?) years of Patriarchal Culture has produced: calculus, the periodic table, the scientific method, Science, the Ideals of Universal Human Rights and the Universality of Human Nature, feminist liberation.. Taking a page from the christian monasteries of the Dark and Middle Ages, I propose building Cultural Refugia. These are self-sustaining communities linked into self-sustaining regional networks of communities that could weather the hard days ahead, preserving what humanity has accomplished and learned. Intentional communities like Transition Initiatives can, in the interim, serve as prototypes and models.


A rather well run initiative in Ontario, Canada:
 

2- The Sixth Extinction. There have been five natural mass extinction events (and about ten minor, sometimes regional, ones) over the earth's history. During a major extinction event half or more of species go extinct in a geologically short period of time. Mass extinctions are dramatic and cause evolution to veer off in novel, unexpected directions. They are times of innovation. But they are rare events, occurring at intervals of tens of millions of years or longer. Thus at least 95% of species go extinct between mass extinction periods, the so-called "background" extinction level.

              Estimates of the human-caused sixth extinction vary a bit from expert to expert but the consensus seems to be that something like 40 - 50% of animals (not species but individuals) on both land and sea have gone extinct over the last four decades! Unbelievable but true. Estimated species extinction rates today are also far elevated over natural "background" extinction rates.

https://www.theguardian.com/environment/radical-conservation/2015/oct/20/the-four-horsemen-of-the-sixth-mass-extinction

3- I have found Lovelock somewhat inconsistent: on the one hand, arguing that Gaia has no ultimate purpose or goal and then inventing bizarre teleologies - goal directed behaviors - that I wouldn't shake a stick at. In one text - which I can't relocate - I recall Lovelock arguing that marine kelp (seaweed) release an iodine containing gas "in order to" transport iodine inland "for the the use of" terrestrial vertebrates. Iodine is used to synthesize an essential metabolism stimulating hormone in terrestrial vertebrate thyroid glands. Such an idea in not absurd, of course. In symbiotic relations, organism A produces something or does something that helps organism B survive and B returns the favor. Scratch my back and I'll scratch yours.. Both parties benefit from this naturally emerging specialization of function, which being acting upon by natural selection, becomes more effective over time. Thus each partner mutates to better match its partner's needs and better exploit the benefits offered by the partner. The hand is shaped to fit the glove, the glove to fit the hand.. Bees evolved to feed on the nectar of flowers and pollinate them in the process. Flowers evolved to feed pollinating bees.

             However, Lovelock's idea that kelp evolved to send iodine inland is incomplete. What benefit do marine kelp get from providing terrestrial vertebrates with essential iodine - the link is not obvious!

             The fact that profs Ward and Kirschvink, as well as other earth scientists writing on evolution,  don't - or rarely - mention the Gaia hypothesis is interesting. Perhaps it is a case of academic snubbing. Lovelock has been criticized for his lack of biological savy before. Recall: he is a physical chemist who invents devices used in detecting and analyzing trace bio-signature molecules, hence his work with NASA designing remote life-detection strategies. Perhaps earth scientists resent the forays of a physical scientist on their turf..

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