August 26th, 2009
After years spent hunting for the buried remains of prehistoric animals, a Canadian paleontologist now plans to manipulate chicken embryos to show he can create a dinosaur. Hans Larsson, the Canada Research Chair in Macro Evolution at Montreal's McGill University, said he aims to develop dinosaur traits that disappeared millions of years ago in birds. Larsson believes by flipping certain genetic levers during a chicken embryo's development, he can reproduce the dinosaur anatomy, he told AFP in an interview.
[Via James Nicoll]
April 16th, 2008
Peter Ward and his colleagues reckon they might have figured out the cause of mass extinctions:
In the deep history of our planet, there have been at least five short intervals in which the majority of living species suddenly went extinct. Biologists are used to thinking about how environmental pressures slowly select the organisms most fit for survival through natural selection, shaping life on Earth like an artist sculpting clay. However, mass extinctions are drastic examples of natural selection at its most ruthless, killing off vast numbers of species at one time in a way that is hardly typical of evolution.
[...] An asteroid probably did kill off the dinosaurs, but the causes of the other four mass extinctions are still obscured beneath the accumulated weight of hundreds of millions of years, and no one has found any other credible evidence of impact craters.
But now, together with Mark Roth of the Fred Hutchinson Cancer Research Center in Seattle, I believe we have found a possible biochemical scar, present within living animals, that links Earth's greatest mass extinction to a single substance: hydrogen sulfide (H2S). Hydrogen sulfide is a relatively simple molecule that gives rotten eggs their distinctive foul odor and is quite toxic — in high concentrations a single breath can kill. And it looks like that is what happened: Hundreds of millions of years ago, hydrogen sulfide probably saturated our oceans and atmosphere, poisoning nearly every creature on Earth. [...]