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UCLA paleobiologist J. William Schopf and colleagues have substantiated the biological origin of the earliest known cellular fossils, which are 3.5 billion years old. The research is published in the March 7 issue of the journal Nature.Schopf and a team of scientists at the University of Alabama, Birmingham have devised a new technique using a unique laser-Raman imaging system that enables them to look inside of rocks and determine what they are made of, providing a molecular map.
"This new technique is a tremendous breakthrough, and is something we have sought for 25 years," Schopf said. "Because Raman spectroscopy is non-intrusive, non-destructive and particularly sensitive to the distinctive carbon signal of organic matter of living systems, it is an ideal technique for studies of ancient microscopic fossils. Raman imagery can show a one-to-one correlation between cell shape and chemistry, and prove whether fossils are biological."
Schopf and his colleagues applied the new technique to ancient fossil microbe-like objects, including the oldest specimens reported from the geological record.
"There is no question at all that we have substantiated the biological origin of the oldest fossils now known," Schopf said. "We have established that the ancient specimens are made of organic matter just like living microbes, and no non-biological organic matter is known from the geological record. In science, facts always prevail, and the facts here are quite clear."
In addition to being a paleobiologist, Schopf is also a geologist, microbiologist and organic geochemist. Director of UCLA's Center for the Study of Evolution and the Origin of Life, Schopf was awarded the 2000 Phi Beta Kappa Award in Science for his book, "Cradle of Life: The Discovery of Earth's Earliest Fossils" (Princeton University Press). The annual award is presented for "outstanding contributions" to the literature of science.
As an honors student at Oberlin College in Ohio in the 1960s, Schopf learned in great detail about the most recent 500 million years of the planet's history. But geologic time covers more than 4.5 billion years, and Schopf's textbooks and professors taught virtually nothing about the Earth's first four billion years. The reason this period was neglected, Schopf learned, was that nobody knew much about it. He vowed to fill that black hole of knowledge, and he explained in "Cradle of Life" how he and other scientists succeeded in doing so.
He is editor of "Earth's Earliest Biosphere" and "The Proterozoic Biosphere: A Multidisciplinary Study," companion books that provide the most comprehensive knowledge of more than 4 billion years of the Earth's history, from the formation of the solar system 4.6 billion years ago to events half a billion years ago.
Schopf's co-authors on the Nature paper are UCLA graduate student Andrew Czaja, who conducts his research in Schopf's laboratory, and University of Alabama, Birmingham physics professors David Agresti, Anatoliy Kudryavtsev and Thomas Wdowiak.
University Of California - Los Angeles. March 2002.
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