Ant colonies show remarkably coordinated behavior, despite lacking any direction from a well-informed central controller. Each worker instead applies simple decision rules to limited knowledge, and exchanges information with her neighbors using rudimentary cues and signals. From this process emerge the construction of complex nests, collective decisions among food sources, the adaptive allocation of labor across tasks, and many other group accomplishments. To identify the underlying decision rules requires a detailed description of the behavior of individually identifiable ants. The ant species Temnothorax curvispinosus is especially useful for this kind of study, because they form small colonies of only a few hundred workers, and they thrive in thin, glass-walled laboratory nests, facilitating detailed video records of their behavior. Most importantly, as shown in these images, workers can be individually marked with tiny drops of paint. Ants are first immobilized with carbon dioxide, and then marked with a distinctive pattern of four drops. They soon emerge unharmed from narcosis, and retain their marks for several months to years. This approach has been particularly useful in showing how emigrating colonies can choose the best among several new homes, even when few individual workers are aware of all the options under consideration.
Credit: Stephen Pratt
A new study looking at 11,000 years of climate temperatures shows the world in the middle of a dramatic U-turn, lurching from near-record cooling to a heat spike.
Research released Thursday in the journal Science uses fossils of tiny marine organisms to reconstruct global temperatures back to the end of the last ice age. It shows how the globe for several thousands of years was cooling until an unprecedented reversal in the 20th century.
Scientists say it is further evidence that modern-day global warming isn’t natural, but the result of rising carbon dioxide emissions that have rapidly grown since the Industrial Revolution began roughly 250 years ago.
The decade of 1900 to 1910 was one of the coolest in the past 11,300 years — cooler than 95 percent of the other years, the marine fossil data suggest. Yet 100 years later, the decade of 2000 to 2010 was one of the warmest, said study lead author Shaun Marcott of Oregon State University. Global thermometer records only go back to 1880, and those show the last decade was the hottest for this more recent time period.
“In 100 years, we’ve gone from the cold end of the spectrum to the warm end of the spectrum,” Marcott said. “We’ve never seen something this rapid. Even in the ice age the global temperature never changed this quickly.”
Written by Seth Borenstein at TPM. Continue HERE
Average global temperature over the last ~2,000 years. Note the massive uptick on the far right side.
Graph via: The Scariest Climate Change Graph Just Got Scarier