Word: extinctions
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...contrast, was most likely a primary weapon - like that of its distant descendant Tyrannosaurus. But that alone wasn't enough of an advantage to let it evolve into the predator that would ultimately dominate North America and Asia. That probably didn't happen until larger predatory dinosaurs went extinct for other reasons, say the scientists, allowing Raptorex-like creatures to begin growing. Once they started to get into the league of the big predators, though, where speed and bone-crushing jaw strength would let them range farther and crunch the bones of the biggest prey, there was no competition...
...same for climate-change policy. If we fail to act now, there is substantial scientific evidence that we may not get another chance. Estimates suggest that if we surpass the two-degree Centigrade limit adapted by the G-8 this summer, 20-30 percent of species could go extinct and more than 1.5 billion people worldwide could face major water shortages. While health care is important, it cannot be the only priority of the Obama administration. A superb health-care system counts for little if the world is no longer livable because of dramatic environmental effects brought on by climate...
...scientists, academics and filmmakers from the British broadcaster visited the South Pacific island of Papua New Guinea this past spring to film a nature documentary and in the process discovered more than 30 new species of animals. Among the unknown creatures - all living inside the crater of the extinct volcano Mount Bosavi - was a giant rat that measured 32.2 in. and weighed more than 3.3 lb., making it one of the largest rodents on Earth (scientists provisionally named the housecat-size animal the Bosavi woolly rat). The historic find also included 16 new species of frogs, at least three...
...turns out that even during the relatively peaceful eras between global calamities, during what is known as background extinction, whole families of species can disappear, pushed out of existence together. And it's not random. According to a new study published in the August 7 issue of Science, vulnerability to extinction runs in families, meaning that some groups of species have a higher likelihood of becoming extinct than others. "It turns out that some branches of the tree of life are more extinction-prone than others," says Kaustuv Roy, a biology professor at the University of California, San Diego. "Those...
...simple bivalves because they have a long and detailed fossil record. Going back to the Jurassic period, researchers analyzed when each genus - a taxonomic category just above species - disappeared, and whether relatives vanished at the same time. On average they found that closely related groups of clams went extinct together at a rate that was more often than expected by blind chance - generally those groups of species were confined to a fairly small geographic area. "Extinctions tend to be clustered, which means the effects tend to be worse than what you might expect from random," says Roy. "That's true...