Palaeobiogeography and the Ordovician and Mesozoic-Cenozoic biotic radiations
A. W. Owen, J. A. Crame, 2002. "Palaeobiogeography and the Ordovician and Mesozoic-Cenozoic biotic radiations", Palaeobiogeography and Biodiversity Change: the Ordovician and Mesozoic–Cenozoic Radiations, J. A. Crame, A. W. Owen
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Curves of taxonomic diversity through geological time consistently show major evolutionary radiations during the Ordovician Period and from the mid-Mesozoic to the present day. Both intervals were characterized by marked biotic provincialism, reflecting episodes of major continental break-up and global tectonism, and their later histories featured steep global climatic gradients. The Ordovician radiation can be recognized at a wide spectrum of taxonomic levels from species to class, and the biogeographical patterns associated with the radiation of individual clades reflect a complex combination of plate distribution, tectonic activity, sedimentary environment, sea-level rise and, ultimately, glaciation. The true scale of the mid-Mesozoic-Cenozoic biotic radiation is currently a topic of intense debate but there is no doubt that it affected plants and animals in both the marine and terrestrial realms. The role of land bridges and ocean gateways in controlling the formation of biodiversity patterns has been a persistent theme in Mesozoic-Cenozoic bio-geography, and a complex set of Neogene tectonic events probably aided the development of both latitudinal and longitudinal provinces during the Cenozoic. The present volume highlights some of the successes across a spectrum of approaches to unravelling the Ordovician and Mesozoic-Cenozoic radiations within the context of palaeobiogeography.
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The study of biodiversity through geological time provides important information for the understanding of diversity patterns at the present day. Hitherto, much effort has been paid to studying the mass extinctions of the Phanerozoic but the research emphasis has now changed to focus on what occurred between these spectacular catastrophic events. After the Cambrian ‘explosion’ of marine organisms with readily preservable skeletons, there have been two intervals when life radiated dramatically — the Ordovician Period, and the mid-Mesozoic-Cenozoic eras. These intervals saw a fundamental reorganization of biodiversity on a hierarchy of biogeographical scales. The size of these diversity increases and their probable causes are topics of intense debate, and there is an intriguing link between the dispersal of continents, changing climates and the proliferation of life.
The papers in this volume are written by palaeontologists, biogeographers and geologists addressing the highly topical field of palaeobiodiversity in the context of the Earth’s changing geography. Palaeobiogeography and Biodiversity Change: the Ordovician and Mesozoic-Cenozoic Radiations illustrates many aspects of the two great episodes of biotic radiation and shows how long periods of time and plate tectonic movements have a fundamental influence on the generation and maintenance of major extant biodiversity patterns.
The volume will be of interest to professional palaeontologists, biologists and geologists, as well as to students in earth and biological sciences.