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Burgess Shale--Evolution's Big Bang†††††††††††††††††††††††††††††††††

February 2 - April 28, 2002

 

An ancient underwater earthquake preserved startling proof of early life forms

Earth formed 4.6 billion years ago, and about a billion years later the most primitive life-form--single celled bacteria--became dominant, and remained so for the next three billion years.

Then a burst of evolutionary creativity, beginning about 600 million years ago, produced complex multicellular animals that appear in the fossil record.Much of what science knows about the "Cambrian Explosion" of life comes from the fossil record in the Canadian Rockies, and especially a site known for its "Burgess Shale," discovered in 1909 by Charles Walcott, then secretary of the Smithsonian Institution.

The shallow waters of the ancient sea once teamed with unusual organisms, as all types of life-forms diversified in the quest for survival.During the Cambrian period the blueprint for virtually all the major groups of animals was laid down in a blink of geologic time.Among these organisms was the two-inch, slightly flattened worm, Pikaia,the first primitive chordate in the sea, ancestor to all vertebrates, such as reptiles, dinosaurs, birds, and mammals.One giant for its time, the 40-inch Anomalocaris, roamed the seas preying with large claws on smaller creatures.

Then at one point along the edges of the Continental Shelf a great underwater mud slide, probably triggered by an underwater earthquake, suddenly buried every living organism within reach in a mass of fine clay silt that filled even their insides, preserving their three-dimensional shapes.The organisms were permanently buried in the dark, in water up to 100 feet deep, with no bacterial life to decay or destroy their bodies.The preserved bodies of this rich, watery biozone were locked forever in a clay-like mud,anatomically true to life, and faithful in every delicate detail of their soft body parts.

Millions of years after the seas had been dried up, the fossil-rich sedimentary rock was raised up by gigantic forces of the Earth.In 1909,paleontologist Charles Walcott stumbled on this mother-lode of exquisitely detailed fossils.Near the Burgess Pass Trail in the Canadian Rockies, he saw an amazing snapshot of the diversity of life from more than 500 million years ago, and glimpsed the "Big Bang" of evolution. Walcott collected tirelessly, and through the years brought back to the Smithsonian more than 65,000 fossils, one of the Institution's greatest treasures.

The evidence of Cambrian life forms in Burgess Shale called for many scientists to rethink the Darwinian theory popular in the Victorian Age, which proposed that evolving life forms moved logically and inevitably along a ladder of progress towards the developmentof the highest form of life.Instead, the evidence of the shale is that an astonishing diversity of life, much of it now extinct, was subject to random accidents and dangers, and only sheer chance has made homo sapiens the dominant life form on Earth today.

Burgess Shale: Evolution's Big Bang is a traveling exhibition from the Department of Paleobiology, National Museum of Natural History, Smithsonian Institution.It is one of the Smithsonian Institution Traveling Exhibition Service (SITES) programs, which share the treasures of the Smithsonian with the general public.

Earth Explorers and the Silk Road --Lectures and Travel††††††††††††††

 

March and April are busy months for the "Earth Explorer" lecture series at the museum. In addition a second presentation about the famous Silk Road region in China will be given.

 

Thursday, March 7The Silk Road: A Cradle of Primate and Human Evolution

Museum scientist Chris Beard, whose expeditions have uncovered exciting new fossil primates along the Silk Road, talks about northwest China as an important crucible of evolution. Museum of Art Theater, 7 pm. members/students/seniors $5; nonmembers, $8.

 

Travel to the Silk Road yourself!The museum is sponsoring a trip from September 17 to October 3, 2002.For information contact Barbara MacQuown, 412.578.2618.

 

 

Thursday, March 14Exploring Active Volcanoes: What can be learned from an often deadly field-based science?†† Dr. Michael Ramsey of the Department of Geology and Planetary Science, University of Pittsburgh, shares his experiences and research in this often risky and hazardous profession.7 pm, Carnegie Museum of Art Theater.Free..

 

 

Thursday,March 21 Earth's Early Atmosphere and Climate. Dr. James Kasting, Professor of Geosciences Meterology, ESSC, Pennsylvania State Univbersity, explains the evolution of Earth's atmosphere, the Snowball Earth episodes that triggered global glaciations, and how organisms and early life survived. 7pm, Carnegie Museum of Art theater.Free.

 

 

Saturday, March 23The Cambrian Explosion: Exploring the Burgess Shale

Join Invertebrate Paleontology collection manager Albert Kollar for a look at the exhibit The Burgess Shale: Evolution's Big Bang, and see the museum's own collection. Workshop 9 am to 1 pm, Orange Classroom,members/students/seniors $5; nonmembers, $8.

 

Saturday, April 6†† Clues from CrocodilesDr. Mary Dawson, the museum's curator of Vertebrate Paleontology, gives an expert look at the millions of years following the extinction of the dinosaurs, as portrayed in When Crocodiles Ruled, now at the museum. members/students/seniors $5; nonmembers, $8.

Thursday, April 11 Time Traveler: The Search for dinosaurs and ancient mammals from Montana and Mongolia.A lecture and book signing by Dr. Michael Novacek, curator of Vertebrate Paleontology at American Museum of Natural History, looks back on his life--the trials and events ofa career that took him to every continent in the world and the discovery of fabulous fossils of mammals and dinosaurs.†† 7 pm, Carnegie Museum of Art Theater.Free.

 

The Earth Explorer Lecture Series is co-sponsored by CMNH, the Department of Geology and Planetary Science of the University of Pittsburgh, and the National Science Foundation.

 

 

Tim Pearce--New Curator of Malacology

 

Tim Pearce, former curator of Mollusks, Delaware Museum of Natural History, has joining the scientific staff of Carnegie Museum of Natural History as the new curator of Malacology, which most of us know as shellfish, and snails. "Malacology" comes from the Latin for "soft" (mollis) and is the study of all those soft-bodied, backboneless creatures that have inhabited the earth for hundreds of millions of years, and often protected themselves with hard shells.

 

The museum has an important collection of approximately three million shells which,when combined with the fossil examples in Invertebrate Paleontology, make a scientific resource of about 3.5 million specimens. For the last 20 years the shell collection has been kept active and maintained by dedicated volunteers and supportive museum scientists.There have been arrangements for donations, loans, and scientific visitors, but no full-time curator.

 

Tim Pearce, as an experienced and well-published expert on mollusks, will give the collection higher visibility as a resource of Carnegie Museum of Natural History.After completing current research on the biogeography of land snails, he expects to research the distribution of land snails of Western Pennsylvania, and produce an atlas of value to agricultural managers interested invasive species, and to conservationists and nature enthusiasts interested in native and rare species.

 

As with other scientific collections, a computerized data base and organization of the material in new cases such as metal compactors (which allow great economy of space) would bring the collection up to the high standard of accessibility and preservation that other research collections now have.Pearce says he is "looking forward to having so many scientific colleagues in the same building, and to being part of a vibrant academic community in Oakland that includes both museum and university experts."

 

Tinysaurus

 

When Discover magazine (January, 2002) highlighted the top scientific discoveries for the year 2001, it included the tiny mammal Hadrocodium wui, which was scientifically described by Dr. Zhe-Xi Luo, associate curator of vertebrate paleontology at Carnegie Museum of Natural History.Weighing no more than a paperclip, this tiny shrew-like creature scurried amid Jurassic-era dinosaurs 195 million years ago.Hadrocodium had a big brain and a tiny body. But, Luo points out, the big brain did not mean the animal was particularly bright, since, "Mammals, even tiny ones, need big brains just to coordinate all their bodily systems."

 

 

Dance to the Fossil Record

To accompany the museumís current exhibit on the Burgess Shale, the Museum of Natural History Store is offering a book titled Planet Ocean: Dancing to the Fossil Record by Brad Matsen and Ray Troll.Writer Matsen and illustrator Troll combine their skills with a playful sense of humor as they journey through the fossil record in this engaging and entertaining history of evolution suitable for teens through adults.

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