In awe of Nature's four billion years on Earth

Where does the inorganic realm of non-life end and life begin?

From Microcosmos: Four Billion Years of Evolution from Our Microbial Ancestors (1986), by Lynn Margulis (1938-2011) and Dorion Sagan (born 1959):

Cyanobacteria

The tasks undertaken by bacterial teams amounts to no less than the conditioning of the entire planet. It is they that prevent all once-living matter from becoming dust. They turn us into food and energy for others. They keep the organic and inorganic elements of the biosphere cycling. Bacteria purify the earth's water and make soil fertile. They perpetuate the chemical anomaly that is our atmosphere, constantly producing fresh supplies of reactive gases.

    The British atmospheric chemist James Lovelock [born 1919] suggests that certain microbially produced gases act as a control system to stabilize the living environment.  Methane, for example, may act as an oxygen regulation mechanism and ventilator of the anaerobic (oxygenless) zone, whereas ammonia—another gas that reacts strongly with oxygen and therefore must be continually resupplied by microbes—possibly plays a major role in determining the alkalinity of lakes and oceans. A so-called greenhouse gas (like carbon dioxide) that lets in more radiation than it lets out, thereby increasing the temperature of the planet, ammonia also may have been important in the control of the ancient climate.
    Methyl chloride, a trace gas in the earth's atmosphere, may regulate the ozone concentration of the upper atmosphere, which in turn has an effect on the amount of radiation which reaches the surface. This influences the further growth of gas-producing microbes. The list goes on and on. The environment is so interwoven with bacteria, and their influence is so pervasive, that there is no really convincing way to point your finger and say this is where life ends and this is where the inorganic realm of nonlife begins.
    ...For tens of millions of years excess oxygen was absorbed by live organisms, metal compounds, reduced atmospheric gases, and minerals in rocks. It began to accumulate in the atmosphere only by fits and starts. Many local populations were killed off, and many adaptations and protective devices evolved. From blue-green cyanobacteria that produced oxygen part-time emerged grass-green bacteria that emitted it continually. Thousands of species of aerobic photosynthesizers arose adapted to rocks, hot water locales, and scums. But by about 2,000 million years ago, the available passive reactants in the world had been used up and oxygen accumulated rapidly in the air, precipitating a catastrophe of global magnitude.
    People are gravely worried today about an increase in atmospheric carbon dioxide from 0.032 to 0.033 percent caused by our massive burning of fossil fuels...The Archeo-Proterozoic world saw an absolutely amazing increase in atmospheric oxygen from one part in a million to one part in five, from 0.0001 to 21 percent. This was by far the greatest pollution crisis the earth has ever endured. [pp. 92-93, 107-108]

In the universe's own image

Lynn Margulis,
mother of her co-author,
science writer Dorion Sagan,
the son of Carl Sagan 

I've found reading harder and harder of late, not sure why.Visually, it's a bit challenging. I get fidgety trying to sit still. There's so much more I'd rather be doing, even trying to sit still enough at my computer to do my "daily blog."
    But what a difference to pick up a book that compels me to read it. Such is Lynn Margulis and Dorion Sagan's book Microcosmos, which I introduced yesterday. From Chapter 1, here's a paragraph that begins below a simplified table labeled "Geological Time Scale," which names the aeons, eras, periods and epochs from 4,500 millions of years ago (when Planet Earth was formed) to 0 millions of years ago (an interesting way to characterize "now"):

Over the first million years of expansion after the Big Bang, the universe cooled from 100 billion degrees Kelvin, as estimated by physicist Steven Weinberg, to about 3,000 degrees K, the point at which a single electron and proton could join to create hydrogen, the simplest and most abundant element in the universe. Hydrogen coalesced into supernovae—enormous clouds that over billions of years contracted from cosmic to submicrocosmic densities. Under the sheer force of gravity, the cores of the supernnovae became so hot that thermonuclear reactions were fired, creating from hydrogen and various disparate subatomic particles all the heavier elements in the universe that we know today. The richness of hydrogen is in our bodies still—we contain more hydrogen than any other kind—primarily in water. Our bodies of hydrogen mirror a universe of hydrogen. [emphasis mine; pp. 40-41]

That image reminds me of the haunting final paragraph of Lewis Thomas's foreword to Microcosmos, a meditation on language, with which his 1974 book, The Lives of a Cell: Notes of a Biology Watcher, was well supplied:

Perhaps we have had a shared hunch about our real origin longer than we think. It is there like a linguistic fossil, buried in the ancient root from which we take our species' name. The word for earth, at the beginning of the Indoeuropean language thousands of years ago (no one knows for sure how long ago) was dhghem. From this word, meaning simply earth, came our word humus, the handiwork of soil bacteria. Also, to teach us a lesson, humble, human, and humane. There is the outline of a philosophical parable here; some of the details are filled in by this book. [p. 12]

    I would enjoy reading The Lives of a Cell again.

Waiting for the real human article

Lewis Thomas (1913-1993)

"We used to believe," wrote Lewis Thomas in 1986, in the foreword to Microcosmos: Four Billion Years of Evolution from Our Microbial Ancestors, by Lynn Margulis (1938-2011) and Dorion Sagan,

that we arrived de novo, set in place by the Management, maybe not yet dressed but ready anyway to name all the animals. Then, after Darwin, we had to face up to the embarrassment of having apes somewhere in the family tree, with chimps as cousins.
    ..."Man's Place in Nature"...[was to] fix Nature up, improving it so that the world's affairs might move along more agreeably; how to extract more of the earth's energy resources, how to preserve certain areas of wilderness for our pleasure [emphasis mine], how to avoid polluting the waterways, how to control the human population, things of that order. The general sense was that Nature is a piece of property, an inheritance, owned and operated by mankind, a sort of combination park, zoo, and kitchen garden.
    This is still the easy way to look at the world...now we seem to be everywhere, running everything, pole to pole, mountain peaks to deep sea trenches, colonizing the moon and eyeing the solar system. The very brains of the earth. The pinnacle of evolution, the most stunning of biological successes, here to stay forever.
    But there is another way to look at us, and this book is the guide for that look. In evolutionary terms, we have only just arrived. There may be a younger species than ours, here and there, but none on our scale, surely none so early on in their development. We cannot trace ourselves back more than a few thousand years before losing sight of what we think of as the real human article, language-speaking, song-singing, tool-making, fire-warming, comfortable, war-making mankind. As a species we are juvenile, perhaps just beginning to develop, still learning to be human, an immature child of the species. And vulnerable, error-prone still, at risk of leaving only a thin layer of radioactive fossils. [pp. 10-11]

"The real human article" is, for me, an evocative phrase. I don't think the real article has arrived yet. It would be much more advanced morally, however advanced technologically it thinks it already is.  It would have developed social and political contexts in which, more or less universally, individuals subscribed to something like the New Ten Commandments and A Declaration of Animal Rights.
    But I fear that the real article will never arrive, given mankind's brief but already evidently disastrous record of success in polluting the planet and of failure to control human population. Mankind seems not to be going to have sufficient time to grow up.
    No laughter attends today's reflection.
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Footnote: For additional quotations from Microcosmos, see the eleventh comment on "Don't forget that you are..." (February 24, 2011).