Out of Thin Air: Dinosaurs, Birds, and Earth's Ancient Atmosphere.OUT OF THIN AIR: Dinosaurs <onlyinclude> This list of dinosaurs is a comprehensive listing of all genera that have ever been included in the superorder Dinosauria, excluding class Aves (birds, both living and those known only from fossils) and purely vernacular terms. , Birds, and Earth's Ancient Atmosphere PETER D. WARD Dinosaurs were the dominant life form on Earth for more than 150 million years. In this book, Ward, a professor of biology and Earth and space studies, proposes an unusual thesis to account for this incredible longevity. At the core of Ward's theory is oxygen, in its unique role in shaping life on Earth. As Ward explains, the atmosphere of ancient Earth was constantly changing, with oxygen concentrations fluctuating in sync with the appearance and disappearance of certain animals. The author traces the critical geological periods Noun 1. geological period - a unit of geological time during which a system of rocks formed; "ganoid fishes swarmed during the earlier geological periods" period during which life emerged, examining each period's fossil record for clues to the evolution of certain body plans, He explains how dinosaur dinosaur (dī`nəsôr) [Gr., = terrible lizard], extinct land reptile of the Mesozoic era. The dinosaurs, which were egg-laying animals, ranged in length from 2 1-2 ft (91 cm) to about 127 ft (39 m). metabolism, form, and reproduction were uniquely suited for this period in Earth's history, Ward asserts that modern bird flight is a vestige vestige /ves·tige/ (ves´tij) the remnant of a structure that functioned in a previous stage of species or individual development.vestig´ial ves·tige n. of the dinosaurs' respiratory system respiratory system: see respiration. respiratory system Organ system involved in respiration. In humans, the diaphragm and, to a lesser extent, the muscles between the ribs generate a pumping action, moving air in and out of the lungs through a becoming adapted to low-oxygen air. Finally, the author ponders what role Earth's ever-changing atmosphere could have on life in the future. Joseph Henry Press, 2006, 282 p., b&w illus., hardcover, $27.95. |
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