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More Slime than Meets the EyeIt sounds like the far-fetched plot of a B-movie: Amorphous slime growing in a lab dish suddenly shows signs of intelligence. But that's exactly what happened recently in a Japanese lab. When researchers put the shape-changing slime mold Physarum polycephalum into a five-inch-square agar gel maze, it filled every available space. But when they added ground oat flakes at the start and finish of the maze, the slime, a single-celled fungus with properties of both plants and animals, began to pull back from the maze's dead ends. In a few hours, its elongated body was stretched along the shortest possible path between the two endpoints. "This remarkable process of cellular computation implies that cellular materials can show a primitive intelligence," write the scientists, led by Toshiyuki Nakagaki of the Bio-Mimetic Control Research Center in Nagoya, Japan, in the September 28 issue of the journal Nature.
CA Gets A+ in Evolution, 19 States FailA study of evolution education in America's public schools found California and five other states doing an excellent job, while 19 other states were failing. The rest of the country's states fared somewhere in between. The study, sponsored by the Thomas B. Fordham Foundation and announced September 26 by the American Association for the Advancement of Science, gave each state a letter grade based on the quality of its evolution education from kindergarten through twelfth grade. The other states receiving "A"s were Connecticut, Indiana, New Jersey, North Carolina, and Rhode Island. The states that received failing grades were Wyoming, Maine, Ohio, Oklahoma, New Hampshire, Florida, Alabama, North Dakota, Georgia, Mississippi, West Virginia, and Tennessee. Kansas, which made news last year by removing the big bang theory from its curriculum and radically de-emphasizing evolution, was in its own category with an "F-".
Oldest Elders Get OlderThe maximum human life span is increasing every year--with no sign of leveling off, according to a team studying 139 years of Swedish national death records. Tracking the age of the oldest person to die in Sweden every year, researchers, led by demographer John Wilmoth of the University of California at Berkeley, saw a gradual rise from 101 years in the 1860s to 105 years in the 1960s. Then, probably as a result of advances in the treatment of cardiovascular disease and stroke, that increase sped up over the next few decades, and the maximum age at death reached 108 in the 1990s. These findings suggest there is no upper limit on age, contradicting the previous estimate of 120 years, made after one study showed that cells in vitro divide only about 50 times. The current study appears in the September 29 issue of the journal Science.
Biodiversity Crisis QuickensThe pace of extinctions worldwide is quickening, according to a new report by the World Conservation Union (WCU). The WCU's 2000 Red List of Threatened Species, published September 28, examines 18,000 species and subspecies around the world. The group of 7,000 experts from nearly every country in the world, added over 200 animal species to the most critically endangered list, including 11 mammals, 14 birds, and 38 reptiles. The WCU's newly updated Red List classifies 11,046 known species at significant risk or extinction and 4,595 on the brink of being declared threatened. One in every four mammals and one in every eight birds is at some risk, the report said. Since 1996, when the last WCU report was published, the number of threatened primates has risen from 96 to 116 and the list of threatened penguins has doubled from five to ten and that of threatened freshwater turtles from 10 to 24. Plants and animals in Mexico and Central America are being threatened at a rate ten times greater than they faced a decade ago, according to the report. The true number of endangered species is anyone's guess, however, as only 1.75 million of the estimated 14 million species on Earth have been documented.
New, Extinct, and Endangered Cambodian SpeciesSeek, it is said, and you shall find. And that is exactly what a group of British explorers did while searching out the animal life in a formerly sealed part of Cambodia. The team discovered dozens of species never before known to science, as well as many endangered species and two--the wolf snake and the Siamese crocodile--that were thought to be extinct. Working in areas riddled with land mines and occupied by the remaining members of the Khmer Rouge, the researchers relied on local guides to avoid the unexploded ordnance. The discoveries add to others recently made in Southeast Asia, which is part of one of the world's biodiversity "hotspots," places where exceptional numbers of endemic species are matched by extensive environmental damage. (Look for an account of the Academy's mission to survey the biodiversity along the border of China and Myanmar in the winter issue of California Wild.)
New Images Shed Light on Sun's CoronaAstronomers have long wondered why the sun's outer atmosphere, or corona, is hundreds of times hotter than the star's surface--the only apparent source of heat--hundreds of thousands of miles below. While new and detailed images of the Sun's surface do not solve the riddle, they may at least give researchers a place to look for the solution. The heating appears to be occurring at the base of huge coronal loops, the largest of which could contain 30 Earths. Somehow, the heat is carried up through the loops into the upper atmosphere. The gorgeous images, sent from the Transition Region and Coronal Explorer (Trace) satellite, will appear in the October 10 issue of the Astrophysical Journal along with analyses by researchers at the Lockheed Martin Advanced Technology Center in Palo Alto.
Gold in the Hills, Mercury in the FishThe Gold Rush that pumped life into California's economy more than 100 years ago now is threatening life in some of the state's lakes and streams, says a report released Tuesday by the U.S. Geological Survey (USGS). Thousands--or even millions--of pounds of mercury, which can damage the nervous system and once was used to separate out gold from the soil, has been leaking from old gold mines and contaminating fish in the northwestern Sierra Nevada. As a result, the state's Environmental Protection Agency is warning everyone to eat a limited number of fish caught in Nevada, Placer, and Yuba counties. And the USGS is working with other federal programs to clean up toxic sites at the old mines. But while the health warnings over tainted fish are the first for California's gold mining country, mercury contamination has previously been found in 12 of the state's bodies of water, including the San Francisco Bay.
Gulf Jellies' Explosion May Endanger FisheriesTwo jellyfish species are posing a major threat to fisheries in the northern Gulf of Mexico, according to marine biologists. One of the jellies is a native whose population seems to be blooming out of control, while the other is a recent invader from Australia. Scientists speculate that three factors are contributing to the rise in jellyfish populations measured over the past 13 years. First, thousands of oil rigs and artificial reefs built in the Gulf have increased the breeding habitat for jellyfish, which require a hard surface to spawn. Second, fishermen have depleted the number of menhaden, a fish that competes with jellyfish for plankton. Finally, farm runoff and industrial pollution increasingly contribute extra nitrogen to the Gulf, creating huge plankton blooms, which are devoured by the jellyfish. Both species of jellyfish are super efficient at clearing the water of fish eggs and larvae. Those larvae that do survive then have to compete with the jellies for food.
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California Academy of Sciences / California Wild / Biodiversity Resource Center
(c) 2000, California Academy of Sciences
/p>(c) 2000, California Academy of Sciences
