As a reader, some of my most serendipitous finds have been plucked off the shelves of used bookshops. Such was the case some years ago with Cradle of Life: The Discovery of Earth’s Earliest Fossils, by J. William Schopf, a fascinating account of how the author in Life in Deep Time1965 was the first to discover Precambrian microfossils of prokaryotic life in stromatolitic sediments in Australia’s Apex chert dated to 3.5 billion years ago, the oldest confirmed evidence for life on earth at the time. My 2017 review of Cradle of Life—nearly twenty years after it was first published—sparked an email exchange with Bill Schopf that later led to his sending me a signed edition of his most recent book, Life in Deep Time: Darwin’s “Missing” Fossil Record.  He did not ask me to read and review it, but naturally I did.

In this work, Schopf—an  unusually modest man of outsize accomplishment—typically credits good fortune rather than his own estimable talents, often emphasizing the centrality of teamwork in the pursuit of sound science, as well as frequently paying tribute to the notion that each discovery and its discoverers are after all “standing on the shoulders of the giants” that preceded them.  A young grad student when he first got into the game, at seventy-seven the author now remains the most significant living survivor of those paleobiologists that devoted decades in an effort to identify and substantiate traces of the most ancient forms of life on the planet.  He feels the clock ticking, and thus is strongly motivated by a desire to leave a record of the journey that led to such consequential discoveries now that most of his peers have passed on.

The result is Life in Deep Time, a curious book—actually something of a blend of three different kinds of books—that succeeds more often than not in its efforts, even if at times it can be an uphill climb for the general reader. It is first and foremost a memoir that dwells for a surprisingly long time on the author’s youth and upbringing, which can be awkward at times because of his decision to employ a third-person limited literary technique in the narrative, so that it is “Bill wondered about …” rather than “I wondered about …” Early on, the reader might grow a bit impatient as Bill negotiates high school, often under the disapproving glare of his father, an admirable man who nevertheless sets impossibly high standards for his son and is quite difficult to please. Yet, even then Schopf is ever the optimist, always grateful for that which goes his way, and treating that which does not as a valuable learning experience. Rather than being scarred from the travails of enduring a demanding parent, he seems to sit in awe of a father who sets challenges that are always another chalk-mark higher than Bill can grasp. Such circumstances for another might leave that child a substance abuser or a ne’er-do-well, but it simply inspires Bill Schopf to be the best-of-the-best, fully absent an uncontainable ego or an axe to grind.

Beyond memoir, the second focal point of the book recounts Schopf’s scientific achievements, while paying tribute to those he worked with, many of whom are little known or entirely unknown outside of the paleobiology community. Science, the author repeatedly underscores, is a team effort. While the ever-modest Schopf does not dodge the recognition he clearly deserves for his key contributions to the field, he makes certain that credit gets appropriately shared among mentors and colleagues and even assistants.

Schopf’s work has spawned controversy that sometimes spilled over into the public arena. In the first case, there was pushback on his remarkable find of those 3.5-billion-year-old microfossils. Peer-reviewed science upheld his claim, although a prominent rival paleobiologist continued to dispute it. In the second, Schopf was brought in by NASA in 1996 to evaluate the extraordinary if premature announcement that life had been identified in a Martian meteorite, which was trumpeted by scientists, politicians and the media. Schopf was skeptical, and subsequent careful research proved him correct. The author’s well-written examination of these controversies is both coherent and enlightening, although blemished a bit by the continued use of that third-person limited literary technique, which feels especially awkward as he answers his critics through the narrative.

Schopf’s greatest triumph was certainly his discovery of those ancient fossils in Australia’s Apex chert, detailed in Cradle of Life and revisited in Life in Deep Time. Modern science has established that the earth is a little more than 4.5 billion years old, but in the mid-nineteenth century, when Charles Darwin devised his theory of evolution, no one could be sure what the true age of the planet was, although most scientists knew it was far older than the six thousand years that theologians claimed. In his groundbreaking 1859 treatise, On the Origin of Species, Darwin estimated that the erosion of England’s Sussex Weald must have taken some 300 million years, but he was taken to task on this by the famed Lord Kelvin, who publicly scolded that the earth could not possibly be older than 100 million years. Whatever the actual number, Darwin was deeply troubled because the process of natural selection that he envisioned would take much, much longer in order for higher life forms to evolve.  In the century that followed Darwin, greater scientific sophistication established the true age of the earth with greater specificity, but it turned out that identifying the planet’s earliest life forms proved quite elusive. This is because traces of these unicellular organisms lacking a membrane-bound nucleus—the prokaryotes that include Archaea and Bacteria—can be maddeningly difficult to identify, and often actually appear to be inorganic remains with strikingly similar characteristics. A famous false positive in this venue set paleobiology back for many decades. As a result, even as late as 1965, Schopf’s find of 3.5-billion-year-old microfossils of prokaryotic life proved controversial, although eventually gained full acceptance by the scientific community.

The science behind all this is remarkably complex, and that is the third focus in Life in Deep Time, a welcome addition for those comfortable with textbooks on paleobiology, but often inaccessible to the general reader.  I am trained in history rather than science, so I found some challenging moments in Cradle of Life that had me re-reading a paragraph or two, but much of it was indeed comprehensible to me as a non-scientist, which is not always the case with the final section of Life in Deep Time, which casually includes sentences such as this one:

“By this time, Bill had gained sufficient knowledge of the chemistry of kerogen, the coaly carbonaceous matter of which ancient microscopic fossils are composed, that he imagined that if the dominating polycyclic aromatic ring structures of the fossil kerogen were irradiated with an appropriate wavelength of laser light, they too would fluoresce and produce the images he sought.” [p186]

Material like this is certainly not impenetrable for an educated reader, but long discourses in this vein can lose a wider audience not schooled in paleobiology. Perhaps this content, although critical to scientists reading the book, might have been better placed in the appendix so as not to lose the flow of an otherwise engaging narrative.

While portions of Life in Deep Time may be difficult to navigate for the general reader, I would nevertheless recommend it. Bill Schopf is a remarkable man, a great scientist and a fine writer. The various threads of the tale he relates here add up to a storied saga of the evidenced-based search for the earliest life on the planet, as well as that of the distinguished if often otherwise anonymous men and women who were responsible for marking one of the greatest milestones in recent scientific history. The voice of Bill Schopf is a humble yet commanding one: it deserves to be heard.


[My review of: Cradle of Life: The Discovery of Earth’s Earliest Fossils, by J. William Schopf, referenced above, is here: ]