Wednesday, February 15, 2006
Richard A. Kerr reports in Science that evolution in a post-extinction world could occur faster. So, as extinctions take place, we may be able to repopulate the planet with new species more quickly than 5 - 10 million years.
The history of life derived from the past half-billion years of marine fossils says it takes 5 million to 10 million years for new species to begin replacing those lost during extinctions. That's bad news for a modern biosphere battered by a human-induced mass extinction. But now researchers have taken a second look at the fossil record after trying to remove some of its imperfections and have concluded that there's no Darwinian traffic cop holding life back. [Taking account of known biases in the fossil record, such as the varying amount of exposed fossil-bearing rock found in different geologic time intervals.. there's no delay between extinction and recovery, although there may be exceptions, such as after the great Permian-Triassic mass extinction. The findings appear in the 21 February issue of Proceedings of the National Academy of Sciences.>