Remnants of ancient life The new science of old fossils

Greenwalt, a researcher at the Smithsonian National Museum of Natural History, debuts with an esoteric examination of ancient biomolecules, or the "DNA, protein, pigments, and other organic material" left behind by ancient animals and plants. Laying out the methods and materials involved in biomolecular research, the author recounts searching for fossils in Montana's Glacier National Park, where he found a fossilized mosquito that he studied using spectrometry technology and determined that the specimen was carrying blood, providing clues about the species' evolutionary history. Ancient pigments, he contends, are essential to understanding the "colors of ancient life, as well as the evolution of color vision." He outlines how melanin evolved from an antioxidant and credits the discovery of bountiful fossil beds in northeastern China with supercharging research into the coloration of dinosaur feathers. Greenwalt's discussion of the quest for ancient DNA and the science behind Jurassic Park entertains, but the academic language ("The calyptrates are thought to have radiated at the beginning of the middle Eocene") will make it difficult for general readers to follow the impressive science. Rewarding if dense, this will appeal to specialists. (Jan.)

Greenwalt, resident research associate at the Smithsonian National Museum of Natural History, guides readers through the relatively new science of paleobiochemistry, which uses the chemical traces left behind by long-dead species to provide new insights into evolution and the biology of ancient life. While most fossils are composed of rock that has replaced once-living tissues or the impressions left by plants and animals in soft mud that has hardened, sometimes actual, physical molecules of the original organisms remain. The range of biomolecules recovered--from pigments that recast the past into vibrant color, to proteins and biopolymers that provide the literal building blocks of connective tissues, horns, feathers, and wood--is astonishing. Especially exciting, though controversial, are claims of finding readable ancient DNA, the blueprint for life. Time, pressure, and heat degrade all of these molecules, so finding samples that can be analyzed with any certainty is a matter of luck, location, and improved methods of detection and analysis. Particularly intriguing is the final chapter that looks toward present-day applications, such as using extinct enzymes to make wood a better source of fuel. VERDICT An accessible book on ancient life that focuses as much on chemistry as on biology.--Wade Lee-Smith