Archaeology Fossil Records Show Biodiversity Comes and Goes

Discussion in 'Archaeology' started by mscbkc070904, Mar 15, 2005.

  1. mscbkc070904

    mscbkc070904 Premium Member

    BERKELEY, CA – A detailed and extensive new analysis of the fossil records of marine animals over the past 542 million years has yielded a stunning surprise. Biodiversity appears to rise and fall in mysterious cycles of 62 million years for which science has no satisfactory explanation. The analysis, performed by researchers with the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California at Berkeley, has withstood thorough testing so that confidence in the results is above 99-percent.

    “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 in taxonomy, because genera classifications are more manageable and less often revised than species classifications; and includes only marine fossils because the records are longer and better preserved than records of land fossils.

    Rest of Story