Although scientists have known since the middle of the 19th century that the tropics are teeming with species while the poles harbor relatively few, the origin of the most dramatic and pervasive biodiversity on Earth has never been clear.
New research sheds light on how that pattern came about. Furthermore, it confirms that the tropics have been and continue to be the Earth’s engine of biodiversity. (more…)
A new study indicates that mass extinctions affect the pace of evolution, not just in the immediate aftermath of catastrophe, but for millions of years to follow. The study’s authors, University of Chicago’s Andrew Z. Krug and David Jablonski, will publish their findings in the August issue of the journal Geology.
Scientists expected to see an evolutionary explosion immediately following a mass extinction, but Krug and Jablonski’s findings go far beyond that.
“There’s some general sense that the event happens, there’s some aftermath and then things return to normal,” said Krug, a research scientist in geophysical sciences at UChicago. But in reality, Krug said, “Things don’t return to what they were before. They operate at a different pace, sometimes more rapidly, other times more slowly. Evolutionary rates shift, and that shift is permanent until the next mass extinction.” (more…)
