What if U.S. history began in 1963, and everything that happened before that year was shrouded in mystery? There would be plenty of events to study, but we wouldn't have a complete picture of the country's past. This is the analogy that paleomicrobiologist J. William Schopf uses to describe the long-missing 85 percent of earth's early fossil record (the puzzle of the missing fossils was known as Darwin's Dilemma). Not until the 1960s did paleobiologists using pickaxes and microscopes find evidence that life began much earlier than previously theorized and that microorganisms were the planet's only inhabitants for most of its existence. And Schopf himself discovered the oldest Precambrian fossils known to science in 1993. Why did it take so long to find these critters?
Though the puzzle of the "missing" early fossil record lived on for more than a hundred years, its solution is now so obvious as to be mundane. The Precambrian world did indeed swarm with living creatures, but until near the close of this vast eon these were microbes and microalgal cells so tiny and fragile that they would never have been unearthed by conventional fossil hunting.
Cradle of Life is a great primer for those interested in the fossil record and its relation to evolutionary theory. Profusely illustrated, this chronicle of amazing discoveries and bizarre questions covers wide ground, including the basics of cell biology and microevolution as well as the careers of the big-name scientists who have set the fossil record straight. And the search continues for the origins of life on earth, as well as the hints of it elsewhere. In a terrifically enlightening epilogue, Schopf shows how even the best scientists have been fooled by geological artifacts that resemble true fossils (as happened with the infamous Martian meteorite "bacteria") and by their own desires to confirm their theories and beliefs about the origins of life. --Therese Littleton
