Word: teething
(lookup in dictionary)
(lookup stats)
Dates: during 1990-1999
Sort By: most recent first
(reverse)
...earliest dinosaurs were meat eaters, how did they evolve into herbivores -- a key to their ability to survive in a variety of environments? The arrangement of teeth and jaws was probably a major factor, and that may explain in part why dinosaurs were so successful overall. Weishampel is trying to correlate tooth design, patterns of tooth wear, the size of the mouth and other aspects of skull mechanics with the types of plants the dinosaurs might have munched. "You can get a rough feeling for how fibrous the material was that they ate, and whether they sheared, ground or pulped...
...dinosaurs' reign, which lasted from 208 million to 144 million years ago. These largest of all dinosaurs include Brontosaurus (an out-of-favor name these days: call them Apatosaurus, or risk correction by a knowledgeable six-year-old). They evidently used their spoon-shaped and pencil-shaped teeth to bite off leaves and twigs, relying, like many modern birds, on gizzard stones to do the actual chewing. Horned dinosaurs like Triceratops, which lived toward the end of the dinosaur era, in the late Cretaceous, had very inefficient jaws. "Their teeth were arranged in a vertical plane, which is very unusual...
...notion that dinosaurs and birds are related dates back over a century. In 1861, quarry workers near Solnhofen, Germany, uncovered the fossil of a pigeon-size creature. Its bone structure and teeth were similar to those of dinosaurs. Yet along with the bones, the 150 million-year-old limestone in which it was trapped had also preserved the unmistakable impressions of feathers and wings. It was ultimately decided that Archaeopteryx, as it was named, was a transitional animal, related to dinosaurs but well along the evolutionary pathway to modern birds...
Mononychus may be the discovery of a lifetime. The turkey-size predator, ! with its mouthful of sharp teeth and long tail, looked quite similar to the theropods. Even so, says paleontologist Mark Norell, it shares a number of features with modern birds. "In Archaeopteryx, for example," he explains, "the fibula ((the thin bone in the leg)) touches the ankle. In birds that doesn't happen, and the same is true of Mononychus. Birds have a keeled sternum ((or breastbone)), where the flight muscles attach. Mononychus also had a keeled sternum." Some of Mononychus' wristbones were fused together, which is another...
...BOTTOM LINE: Tony Randall and Jack Klugman play another odd couple -- but this time the laughs are like hen's teeth...