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Modern Forests Can Handle More Carbon Dioxide and Ozone than Previously Thought.
Researchers at the University of Michigan have some much needed good news about North American forests. A 12-year study of forest trees in northeastern Wisconsin held some surprises for scientists studying the effects of increased carbon dioxide and ozone on forest trees. When trees were exposed to artificially increased levels of carbon dioxide, they absorbed the gas faster and grew at an accelerated rate during the entire period of the study. Nor did exposure to increased levels of ozone disrupt this growth trend. Ozone-resistant species simply picked up the slack and overall tree growth was not adversely affected. The results could mean that at least in North America, forests might fare better than thought even if future carbon dioxide and ozone levels are much higher.
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Humans Used Paint for Symbolism 100,000 years ago.
In a South African cave, researchers uncovered evidence that pushes back human ritual paint use to about 100,000 years ago. By grinding iron-oxide laden dirt (ocher) and mixing it with bone marrow and some charcoal, these early modern humans produced a red paint. The paint was placed in a shell, such as abalone, and a stone spatula was used to apply it. This discovery beats the previous findings of paint factories that had been dated no earlier than around 60,000 years ago, and it is far older than the famous Lascaux cave drawings, which date back to around 17,000 years. The findings are particularly significant because anthropologists believe that ritual use of paints by cave-dwelling humans argues for a much earlier start to symbolism and abstract thinking.
Read the full story at New York Times.
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Black Plague Genome Sequenced.
Scientists from the University of Ontario and the University of Tubingen in Germany have for the first time determined the genetic code of the bacterium that cause one of the most horrific plagues ever recorded. The Black Death decimated Europe in the 14th century and may have killed off almost one-half of the population. The bacterium responsible, Yersinia pestis, is still active today, but it is susceptible to modern antibiotics and its present genome may be slightly different from the one that was stalking Europe at the time of the Black Death. Scientists re-constructed the genetic code of the bacterium by using DNA fragments from samples taken from a mass grave near London. They intend to next re-create the bacterium, under strictly controlled conditions, in order to understand why the Black Death variant was so virulent.
Read the full story at New York Times.
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What’s Rover Trying to Say? Ask Your 9-Year-Old.
When it comes to understanding the meaning behind dog barks, children are more gifted than adults. In an experiment that used tape-recordings of dogs barking in different situations, children between the ages of 8 and 10 scored better than older children and adults at correctly recognizing the context of the bark. They were especially good at understanding whether the dog was expressing playfulness, fear or loneliness. Apparently, all the participants, young or old, could tell an angry bark. Exactly what can be inferred from this work is less clear. However, the experimenters hypothesize that humans may have an innate ability to understand some animal vocalizations, but that this ability diminishes as we mature.
Read the full story at Discovery.
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Did the Evolution of Mammalian Clotting System Inevitably Lead to Heart Attacks?
Cardiovascular disease is a leading cause of death among humans. Platelets, small nucleus-free round blood cells that have the tendency to stick to themselves, are a contributing factor in arterial plaque and therefore cardiovascular disease. So why do we have platelets? All mammals have platelets because they allow blood to quickly clot. Non-mammals, such as birds, employ a different system involving larger cells called thrombocytes. When researchers compared birds and mammals, they found that platelets are much more effective clotting agents than thrombocytes. The researchers believe that mammals evolved platelets because they were so effective at protecting mammals from traumatic injury and severe blood loss. The price, however, may be our susceptibility to cardiovascular disease.
Read the full story at Science Daily.
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Is Life Sweeter for the Sweet-Tooth?
A paper recently published in the Journal of Personality and Social Psychology concludes that individuals who are particularly fond of sweets tend to have more “pro-social” personalities. The authors claim that there is a link between altruistic behavior and the love of sweet tastes, as revealed by experiments. In one part of the study, volunteers who were given sweets proved to be more likely to help in a communal activity than those who were given non-sweet food. Assuming the correlation holds up, whether love of sweets is the cause or the effect of altruism is not clear.
Read the full story at Science Daily.
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Pitching Dog Food at Ultra-high Frequencies.
In what might be a new low for ad agency machinations, an entirely new kind of dog product advertising, already being shown in Austria, includes high frequency whistles and noise that dogs, but not humans, can hear. Subliminal advertising for human viewers has been banned; however, this is a clever twist. A pet owner who sees their dog reacting to a television commercial about a particular dog food could very well assume that Fido is excited about the product rather than reacting to the ear-splitting noise the television is suddenly making but the owner doesn’t even hear.
Read the full story at Discovery.
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Biological “Logic Gates” Take Biologically Based Computing A Step Closer to Reality.
Scientists at the Imperial College in London have successfully fashioned bacterial material and DNA into a computing element. They have created prototypes of biological logic gates – the fundamental elements of electronic computing. There is little doubt that these new logic gates will be able to do basic computing. However, one exciting possible application for DNA-based logic gates is to build nano-scale biologically-based machines that can enter the human body in search of cancer cells and other diseases. These would be the medical devices of the future and their potential could be virtually unlimited.
Read the full story at Red Orbit.
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If It Ain’t Broke – 2.5 Million-Year-Old Tiger Fossil Shows Few Changes.
A skull fossil recovered from Eastern China in 2004 has been studied since and scientists now conclude that it provides evidence that the ancient species is closely similar to modern tigers. Even though this species of tiger lived around 2.5 million years ago, the structural similarity of its skull to that of modern tigers is striking. The authors postulate that the ancestors of the tiger had been a successfully adapted creature, and therefore evolutionary change offered few survival benefits.
Read the full story at National Geographic.
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Robo-bugs With Wings Shed Light on Evolution of Flight.
A six-legged robotic “bug” is the creation of scientists at the University of California, Berkeley. The battery-powered artificial insect was already able to run at impressive speeds when the scientists decided to attach to it artificial wings harvested from an inexpensive child’s toy. Once the wings were integrated, the robo-bug’s stability, up-hill performance and overall running speed were significantly increased, even though it could not lift off and fly. It could, however, now glide and tests showed that gliding allowed it to survive much higher falls and re-orient itself as it fell to the ground. However, the real payoff of this experiment may be what it implies about the evolution of flight. If the robo-bug is any guide, it suggests that the order of evolution may have been wings, gliding and then winged flight.
Video of the robo-bug in action:
Read the full story at Science Daily.
“The Dirt: This Week in Nature” curated and written by Robert Raciti.