THE TERRESTRIAL ENVIRONMENT AND THE ORIGIN OF LAND VERTEBRATES

Abstract

Some 405 million years ago multicellular plants and animals began a slow colonization of the continents.First traces are in the shallow waters of the Late Silurian, followed by rapidly increasing records of plants during the Devonian and invertebrates and vertebrates from the late Devonian and Carboniferous.Much of the earliest history of both the animals and plants remains obscure, but in the 19th and 20th centuries, during which speculation and accumulation of data has gone on apace, substantive data have been accumulated and ways of looking at the problems have changed immensely.An older way of looking at evolution during the later Paleozoic through a group-by-group analysis has partially given way to coordinated studies of associations of organisms in community systems and considerations of the ecology and taphonomy of their occurrences.A. L. Panchen, the moving force behind the symposium presented in this volume, expanded the original plan to treat the origin of tetrapods from their fish ancestors, to include plants, invertebrates and vertebrates and the field of ecological aspects of the origin of tetrapods.The result has been a happy synthesis of morphology, systematics, ecology and taphonomy within an evolutionary framework.Altogether 20 students have contributed to the volume.Topics range through biogeography, plants, invertebrates and vertebrates viewed in a variety of contexts.The volume is a gold mine of information on the origin of tetrapods and related subjects.To one who has been interested in this area for many years and watched attitudes and philosophies change, one of the striking aspects of the volume is its clear portrayal of the continuing controversy between so called "orthodox" and "cladistic" systematics and phylogenetics.The broad impact of the development of cladistic methods, as presented by Hennig and greatly modified to date, is evident throughout the book, even in the papers of some who reject the approach.Awareness of the need to erect testable hypotheses is found in the majority of papers.Although the method has had a strongly affirmative effect on systematics and phylogeny, it remains clear that in the initial steps of analysis, and , The Terrestrial Environment and the Origin of Land Vertebrates.