This illustration depicts the food web for ecological groups in the late Cretaceous Period as reported in a new paper published in the Proceedings of the National Academy of Sciences. Each ecological group includes a set of species that share the same set of potential predators and prey. Silhouettes show iconic members of each group. Arrows show who eats whom. (Credit: Courtesy of Jonathan Mitchell, Peter Roopnarine and Kenneth Angielczyk)
 
 The Cretaceous Period of Earth history ended with a ...
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Social animals usually congregate for protection or mating or to capture bigger prey, but a University of California, Berkeley, biologist has found that the terrestrial hermit crab has a more self-serving social agenda: to kick another crab out of its shell and move into a larger home.

All hermit crabs appropriate abandoned snail shells for their homes, but the dozen or so species of land-based hermit crabs -- popular terrarium pets -- are the only ones that hollow out and remodel their shells...

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New imaging technology has revealed how the molecular machines that remodel genetic material inside cells 'grab onto' DNA like a rock climber looking for a handhold. 

The experiments, reported in this week's Science, use laser light to generate very bright patches close to single cells. When coupled with fluorescent tags this 'spotlight' makes it possible to image the inner workings of cells fast enough to see how the molecular machines inside change size, shape, and composition in the presenc...

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Most of the more than 6,000 species of frogs in the world lay their eggs in water. But many tropical frogs lay their eggs out of water. This behavior protects the eggs from aquatic predators, such as fish and tadpoles, but also increases their risk of drying out. Justin Touchon, post-doctoral fellow at the Smithsonian Tropical Research Institute, discovered that climate change in Panama may be altering frogs' course of evolution.

By analyzing long-term rainfall data collected by the Panama Can...

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One of the lowest mass supermassive black holes ever observed in the middle of a galaxy has been identified, thanks to NASA's Chandra X-ray Observatory and several other observatories. The host galaxy is of a type not expected to harbor supermassive black holes, suggesting that this black hole, while related to its supermassive cousins, may have a different origin.

The black hole is located in the middle of the spiral galaxy NGC 4178, shown in this image from the Sloan Digital Sky Survey. The ...

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Artificial muscles and self-propelled goo may be the stuff of Hollywood fiction, but for UC Santa Barbara scientists Omar Saleh and Deborah Fygenson, the reality of it is not that far away. By blending their areas of expertise, the pair have created a dynamic gel made of DNA that mechanically responds to stimuli in much the same way that cells do.

The results of their research were published online in the Proceedings of the National Academy of Sciences.

"This is a whole new kind of responsive g...

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By blending optical and atomic force microscope technologies, Iowa State University and Ames Laboratory researchers have found a way to complete 3-D measurements of single biological molecules with unprecedented accuracy and precision.

Existing technologies allow researchers to measure single molecules on the x and y axes of a 2-D plane. The new technology allows researchers to make height measurements (the z axis) down to the nanometer -- just a billionth of a meter -- without custom op...

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 The rise of the Rocky Mountains and the appearance of a major seaway that divided North America may have boosted the evolution of new dinosaur species, according to a new Ohio University-led study.

"Over the past century, paleontologists have found a wide variety of dinosaurs in rocks dating to around 75 million years ago, but right before the asteroid hit at the end of the Cretaceous, there appeared to be fewer species in North America," he said. "The reason for this discrepancy in dinosaur ...

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Favourable configuration of ESA's Cluster mission spacecraft, scientists have detected and characterised lower hybrid drift waves, a special kind of plasma waves that develop in thin boundaries both in space and in the laboratory. The measurement of fundamental properties of these waves was possible when two of the spacecraft were flying very close to one another in the tail of Earth's magnetosphere. With wavelengths of about 60 km, these waves appear to play an important role in the dynamics...

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