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5 December 2013 11:26 am ,
Vol. 342 ,
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
Thousands of scientists in the Russian Academy of Sciences (RAS) are about to lose their jobs as a result of the...
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
Snake venoms are remarkably complex mixtures that can stun or kill prey within minutes. But more and more researchers...
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
Since arriving on the island of Guam in the 1940s, the brown tree snake ( Boiga irregularis ) has extirpated native...
- 5 December 2013 11:26 am , Vol. 342 , #6163
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ScienceShot: Life After Extinction
29 April 2013 3:05 pm
Mass extinctions have a silver lining, providing opportunities for marginalized creatures to rise to power. While that notion seems obvious, it hadn't been demonstrated for the end-Permian extinctions, which occurred about 252 million years ago and wiped out about 90% of life on Earth. So, researchers took a detailed look at the numbers and distribution of land-dwelling species at five sites scattered across the southern part of Pangaea, the supercontinent that existed at the time of the die-offs. (Previous analyses had looked at only trends in marine species or for limited regions on land, the team notes.) Of the 62 species found at the sites about 5 million years before the die-offs, 21 (or about 34%) were found in two or more of the sites, suggesting a wide distribution of those creatures. But 10 million years after the end-Permian extinctions, only five species out of 68—none of which matched the 62 that lived before the die-offs—were found at more than one site. The analysis also reveals that after the mass extinctions, species typically had smaller, less-connected geographical ranges than did the species living before the die-offs, the researchers report online today in the Proceedings of the National Academy of Sciences. Altogether, the trends suggest that when widely prevalent creatures such as the pig-sized Dicynodon (left) were removed from the scene, species such as the 3-meter-long Asilisaurus (right)—a member of the archosaurs, which included dinosaurs and many groups alive today, such as crocodilians and birds—could diversify and thrive.
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*Correction, 9:25 a.m. on 30 April: This article has been updated to remove mammals from the list of living groups within archosaurs.