Paleontologists tackle history of life
Molecular sequencing, computer programming and electronic databases advance field

By Diane Ainsworth, Public Affairs


old guy

This impression of an early, snail-like animal, about 555 million years old, was recovered from the White Sea in northern Russia. New techniques in DNA analysis and molecular biology are allowing paleontology students to date these specimens and reconstruct their evolutionary paths despite their relative absence in the fossil record.
Image and reconstruction courtesy of M.A. Fedonkin and Jere H. Lipps

11 July 2001 | The planet hums with life, flamboyant and obvious as it scampers by, roars out or gallops past at breakneck speed. From the first appearance of microscopic bacteria 3.5 billion years ago to an 11,000-year-old saber-toothed tiger, Earth’s continuum of life, past and present, has been chronicled in rock, the stuff of which paleontology careers are made.

“Our jobs would be easy,” explained one expert at the North American Paleontology Conference, an international gathering of scientists who met on the Berkeley campus recently to wrestle with fundamental issues in Earth’s prehistory, “if Earth’s crust wasn’t forever rearranging itself…if scholars had a clear record of the Earth’s crust and life’s ebb and flow.”

Life’s flow has been fitful, the experts said, with at least five near extinctions. But even with a pristine record of some of those catastrophic events — such as the Cretaceous/Tertiary extinction and recovery — paleontologists grappled with ways of explaining what happened. And why some species were able to persist, while others died out?

In one daylong session, new evidence, gleaned from huge electronic databases made possible by the Internet, was presented to help illuminate the last near extinction — the one that wiped out the dinosaurs 65 million years ago. Considered a mere setback, a hiccup, rather than a turning point in the diversity of new kinds of life on this planet, scholars are rewriting old theories to show, as does a new study from the National Academy of Sciences, that the height of diversity in new kinds of plants and animals may have come and gone more than 400 million years ago.

“As you can see, these new databases are beginning to call into question longstanding views of the diversity of life,” said John Alroy of UC Santa Barbara’s National Center for Ecological Analysis and Synthesis. His National Science Foundation-funded “Paleobiology Database” is painting a radically different picture of the rise and fall of diversity that seems to be more in sync with the new National Academy study.

“Computing power is allowing us to build new databases of paleontological research to address some of the really big scientific questions, like how organisms respond to major changes in their environment,” said Anthony Barnosky, a Berkeley associate professor of integrative biology in the Museum of Paleontology and Department of Integrative Biology, who organized the session devoted to bioinformatics and paleobiology databases. “This kind of online biodiversity data wasn’t around 10 years ago.”

The conference, held approximately every five years, continued a tradition that began in 1969 in Chicago.

In addition to bioinformatics and applications of paleontological information to other disciplines, conference participants discussed such topics as the preservation of fossils found on public lands; new techniques in molecular biology to date lineage; the evolution of biodiversity from the mid-Cretaceous period (100 million years ago) to present; the spread of grasslands in the late Tertiary (65 million to 1.8 million years ago); and artificial life, which delves into biologically inspired software systems and synthetic animals that are capable of learning new behaviors and evolving.

More than a quarter of the 450 paleontologists were graduate and undergraduate students eager to debate evolutionary changes and cataclysmic events at the boundaries of each geologic epoch, said Jere Lipps, conference chair and a paleontologist in the Museum of Paleontology.

“An absence of fossils in the record, such as those occurring in the Precambrian, are being studied using new techniques, such as molecular sequencing,” he said.

“For instance, we don’t have any fossil evidence of animals living before 580 million years ago. At about 580 to 560 million years ago, soft-bodied animals and primitive plants appeared,” he said. “Some of our graduate students are using molecular sequencing to retrace the evolution and distribution of living species and fauna to fill in those gaps.”

Other experts brought ideas from some unusual fields, like computer sciences, to fuel the paleontology debates. They probed the rudimentary laws of evolution itself and asked if life — artificially designed — might help explain nature’s ways.

“Who knows how evolution really works?” said Roy Plotnick, a professor of earth and environmental studies at the University of Illinois, Chicago. “We wanted to bring together computer scientists, paleontologists and artists to exchange ideas about evolutionary modeling and ways of programming behavior in nonbiological systems, because their ideas can shed some light on our theories.”


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