Dragonflies with hawk-sized wing spans and millipedes longer than a human leg lived more than 250 million years ago. Scientists have long wondered why sci-fi bugs don't exist today. The reason has to do with a bottleneck that occurs in insects' air pipes as they become humongous, new research shows. In the Paleozoic Era, insects were able to overcome the bottleneck due to a high-oxygen atmosphere. Unlike animals with backbones, like us, insects deliver oxygen to their tissues directly and bloodlessly through a network of dead-end tracheal tubes. In bigger insects, this mode of oxygen transport becomes less efficient, but no one has been exactly sure why. Alex Kaiser of Midwestern University and his colleagues at Argonne National Laboratory and Arizona State University delved deeper by shining X-rays on four living beetle species , ranging in body mass by a factor of 1,000. This allowed the team to measure the exact dimensions of the beetles' tracheal tubes. Kaiser found that bigger … [Read more...] about Why Bugs Are Not Huge
For instance, when a person touches a hot stove, the molecules in his hand sense heat, transmit that information to the brain, and the brain then tells the molecules of the hand to move. Such two-way information flow governs the behavior of simple and complex life forms alike, from the tiniest bacteria to the giant humpback whale. By contrast, if you put a cookie on the stove, the heat may burn the cookie, but the treat won't do anything to respond. … [Read more...] about Origin of Life Needs a Rethink, Scientists Argue
When Mount Toba erupted on the Indonesian island of Sumatra some 74,000 years ago, ash fell like snow on the Indian subcontinent, including on human toolmakers who had shaped stone flakes into sharp cutting instruments. Debate over the identity of these craftspeople—and whether a cataclysmic “volcanic winter” wiped them out—has raged for decades, because it has implications for when our species first left Africa. A new study of these people’s tools suggests they not only survived the eruption, but thrived for another 50,000 years. Others, however, say there isn’t enough evidence that the tools were made by Homo sapiens at all. … [Read more...] about Humans in India may have survived supereruption 74,000 years ago
He found "quite a difference between the butchering marks and projectile impact marks," he says. His study revealed six types of distinctive projectile impact wounds, from drag marks to fracture marks and punctures. O'Driscoll also noted that most projectile impact marks were located on vertebrae or rib bones and that 17% percent of the marks overall—and 50% of the punctures—held microscopic bits of embedded stone from the flint points, due to the high velocity of impact. By contrast, none of the butchering marks contained such stone fragments, another key distinction. … [Read more...] about When Did Humans Begin Hurling Spears?
ReDigi argued that it was protected both by fair use and by the first sale doctrine, which allows for a good to be resold. Recently, the Supreme Court ruled in favor of first sale rights, protecting the rights of a used book vendor to import cheaper textbooks from Thailand to the United States. But here, the judge disagreed with ReDigi's premise: … [Read more...] about “Can I resell my MP3s?” redux—federal judge says no