"What we're seeing is a real and very strong signal that the history of life on our planet has been shaped by a 62 million year cycle, but nothing in present evolutionary theory accounts for it," said Richard Muller, a physicist who holds joint appointments with Berkeley Lab's Physics Division, and UC Berkeley's Physics Department. "While this signal has a huge presence in biodiversity, it can also be seen in both extinctions and originations."
Muller, and his grad student, Robert Rohde, presented their findings in the March 10, 2005 issue of the journal Nature. In a commentary on this research in that same issue of Nature, UC Berkeley professor of earth and planetary sciences, James Kirchner, stated, "It is often said that the best discoveries in science are those that raise more questions than they answer, and that is certainly the case here."
Muller and Rohde discovered the 62 million year fossil diversity cycle after creating a computerized version of an exhaustive database compiled by the late University of Chicago paleontologist Jack Sepkoski. Entitled Compendium of Fossil Marine Animal Genera, Sepkoski's posthumously published database is the most complete reference available for the study of biodiversity and extinctions. It covers the Phanerozoic eon, the past half billion years during which multicellular organisms left abundant fossil records in rocks; uses genera, the level above species i
Contact: Lynn Yarris
DOE/Lawrence Berkeley National Laboratory