December 18, 2007


Asteroids Key to Biodiversity Boom? (Larry O'Hanlon, 12/17/07, Discovery News)

A shattered asteroid may have sprayed Earth with high-speed debris 470 million years ago and spurred one of the biggest bursts of biodiversity in Earth's history, rather than wiping life out.

The period of moderate to heavy meteorite bombardment appears to match the time at which many new species of animals evolved, called the Great Ordovician Biodiversification Event in the Middle Ordovician period, say geologists.

"Although this event represents the most intense phase of species radiation during the Palaeozoic era...the causes of this event remain elusive," report Birger Schmitz of the University of Lund, Sweden, and his colleagues in the December issue of Nature Geoscience.

Design changes.

Posted by Orrin Judd at December 18, 2007 8:16 AM

Isn't it suspicious that to account for the truly significant biological events external events are invoked, and they conveniently have opposite effects depending on what is being explained -- here an asteriod increases diversity, yet a later asteriod is supposed responsible for the mass extinction of the dinosaurs.

Posted by: jd watson at December 18, 2007 3:29 PM

jd: In literature, this device is known as the Deus ex machina.

Posted by: Lou Gots at December 18, 2007 6:56 PM

In literature, this woud be called a Deus ex Machina. Now in biology, . . ..

Posted by: Lou Gots at December 18, 2007 7:41 PM
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