Cradle of Life: The Discovery of Earth’s Earliest Fossils. – book review
John J. Ernissee
by J. William Schopf. Princeton University Press, Princeton, N. J. 1999; $45 (hardbound, 336 pages), $17.95 (softbound, 367 pages).
Charles Darwin’s theory of evolution began life with a serious dilemma overshadowing it–the missing Precambrian fossil record. Schopf quotes the great master of evolution thusly:
There is another … difficulty, which is much more serious. I allude to the manner in which species to several of the main divisions of the animal kingdom suddenly appear in the lowest known [Cambrian-age] fossiliferous rocks…. If the theory [of evolution] be true, it is indisputable that before the lowest Cambrian strata was deposited, long periods elapsed … and that during these vast periods, the world swarmed with living creatures…. [However], to the question of why we do not find rich fossiliferous deposits belonging to these assumed earliest periods prior to the Cambrian system, I can give no satisfactory answer. The case at present must remain inexplicable; and may be truly urged as a valid argument against the views here entertained. (p. 15; insertions by Schopf)
Darwin would have been completely mesmerized by Schopf’s book, which explains and illustrates how scientists have filled in the missing record and have fleshed out the major features of the early origin and development of life on planet Earth. The book, however, is not targeted to the cognoscenti but is entirely accessible to a lay audience, albeit one not frightened by scientific terminology. Schopf is careful to explain all of the quite-necessary terms and has appended a full glossary. It becomes clear, as one works through the book, that the technical details are needed–the major hurdles that life had to overcome mostly involved developing new chemical processes, such as photosynthesis. Schopf is a patient explainer, one who intersperses the more serious science with anecdotal asides about the history of the search for evidence of the earliest biosphere, about the scientists (and some of their foibles), and about his own contributions to the field.
There is also a metatheme to the book, that of how science is, or ought to be, done. The earliest days of the search for early life were characterized by some overblown claims and counterclaims. Later, as microscopic evidence began to accumulate, misidentifications were rather common, to the embarrassment of the scientists involved. Schopf ends his book with a section titled “Extraordinary Claims! Extraordinary Evidence?” In it, he discusses a number of historical incidents, including “Beringer’s Lying Stones,” a story that often appears in elementary geology texts, having become an almost legendary caution about gullibility and “leaping to conclusions.” Yet Schopf partially rehabilitates the good Dr. Beringer, showing that he had proceeded to the best of his ability, in light of the beliefs of the time, and had examined and rejected several alternative hypotheses before making his claims. And, as Schopf says, “… it’s a sure bet that some of what passes as `known’ today will eventually turn to dust. Still, we can take heart, for Beringer and Scheuchzer show that even when human foibles sidetrack the search for knowledge, the path will be regained.” It is this relentless self-correction that is so often forgotten or ignored by casual critics of science, especially those who point their fingers at such spectacular scientific “goofs” as “cold-fusion.”
There is another point to Schopf’s discussion of Beringer and Scheuchzer. Recently, he was part of a team examining the so-called Life from Mars. Mysterious, very tiny and nondescript rodlike objects were found in meteorites that are believed to have come from Mars. Scientists at the Johnson Spacecraft Center thought they were fossil organisms, a view that Schopf, after being invited to examine them, did not share. However, the cautious and skeptical approach to the fossils was quickly lost in a feeding frenzy of media reporters paying attention only to the sensational. Schopf’s skeptical voice was drowned out by the proponents from the Johnson Spacecraft Center. Schopf carefully reviews the evidence in the book and shows why he remains highly doubtful that what has been thus far examined is any evidence of life at all. No doubt there will be much more published about these so-called fossils, both pro and con; and perhaps as more data become available, it will be possible to confidently say that these mysterious, tiny objects are or are not fossils. But, as Schopf says, extraordinary claims demand extraordinary evidence. This level of evidence is yet to be had.
At times, this is a demanding book to read–at other times, it is genuinely delightful. I recommend it highly, but with the caveat that the reader will have to work a bit to gather all the riches contained therein.
John J. Ernissee
Clarion University, Pennsylvania
COPYRIGHT 2002 Heldref Publications
COPYRIGHT 2002 Gale Group