Creating the animal planet: The Crucible of Creation—The Burgess Shale and the Rise of Animals by Simon Conway Morris, and The Garden of Ediacara—Discovering the First Complex of Life by Mark A.S. McMenamin

Abstract

Oxford University Press, 1998. £19.99 hbk (xxiii + 242 pages)ISBN 0 19 850256 7.Columbia University Press, 1998. £23.95/$29.95 hbk (xii + 295 pages)ISBN 0 231 10558 4.One of the most dramatic macroevolutionary problems is the origin of multicellular animals and the major animal body plans. The millions of animal species fall into 35 or so phyla, such as arthropods, mollusks, nematodes, echinoderms and chordates, each exhibiting a distinct body plan. Beginning with Ernst Haeckel in the late 19th century, zoologists looked for ancestors among the embryos characteristic of particular groups of phyla. A marvelous speculative evolutionary zoology arose that was populated by alliterative but fictive ancestors. However, paleontology, which should have been the ideal window into metazoan origins, was stymied. A profusion of complex animals all appeared with embarrassing suddenness in the fossil record in the early Cambrian, 545–535 million years ago: the so-called ‘Cambrian explosion’. No amount of rock-pounding by frustrated paleontologists produced any indubitably older animal fossils.The quandary of metazoan origins, which slept fitfully for much of the 20th century, has reawakened. New cladistic and molecular approaches to phylogeny made possible a re-evaluation of relationships among phyla. Although the old groupings of protostome and deuterostome superphyla still hold, some striking reinterpretations of relationships among phyla have emerged1xAguinaldo, A.M.A. et al. Nature. 1997; 387: 489–493Crossref | PubMed | Scopus (1091)See all