Search results for "Origination"
showing 9 items of 9 documents
Unravelling extrinsic and intrinsic factors of the early Palaeozoic diversification of blastozoan echinoderms
2010
19 pages; International audience; The Subphylum Blastozoa represents more than one third of the early Palaeozoic echinoderm fauna. A comprehensive database including all records of blastozoans was built to provide quantitative analyses of palaeogeography and diversity patterns and processes, for the 10 classes currently included in this subphylum during the early Palaeozoic. The global pattern of taxonomic diversity shows two peaks during the Cambrian Series 3 and the Late Ordovician intervals. In Cambrian times, the high taxonomic diversity seems to be related with a high turnover rate and a high endemicity of blastozoan genera, whereas in Ordovician times, the rise in diversity is associa…
Exploring the major depletions of conodont diversity during the Triassic
2014
International audience; In this paper, we show that the Triassic fossil record reflects just two great depletions of conodont diversity before the Rhaetian, which occurred in the Smithian (Olenekian, Early Triassic) and in the Julian (Carnian, Late Triassic). By exploring this context, our results highlighted that they respond to different origination?extinction dynamics. Thus, while the Smithian diversity depletion can be interpreted as a consequence of elevated extinction, the Julian diversity depletion was triggered by fluctuations in origination regime. This evidence suggests that, despite the role of extinction on diversity losses, conodonts suffered crucial changes on the origination …
Ammonite Faunal Dynamics Across Bio-Events During the Mid-and Late Cretaceous Along the Russian Pacific Coast
2012
The present paper focuses on the evolutionary dynamics of ammonites from sections along the Russian Pacific coast during the mid-and Late Cretaceous. Changes in ammonite diversity (i.e., disappearance [extinction or emigration], appearance [origination or immigration], and total number of species present) constitute the basis for the identification of the main bio-events. The regional diversity curve reflects all global mass extinctions, faunal turnovers, and radiations. In the case of the Pacific coastal regions, such bio-events (which are comparatively easily recognised and have been described in detail), rather than first or last appearance datums of index species, should be used for glo…
Plant fossil record and survival analyses
2012
Cascales-Minana, B. & Cleal, C.J. 2011: Plant fossil record and survival analyses. Lethaia, Vol. 45, pp. 71–82. Survival analysis is a classic palaeobiological method widely used on the animal fossil record. This study reports the first application of survivorship analyses on the plant fossil record from a global viewpoint and provides a new comparative approach of this methodology. The results reveal three important plant extinction events in the history of plant life at a global scale. The results also clearly suggest that the origination events are more intensive than extinction processes and that the origination moment of several lineages of vascular plants is an important factor that c…
Trends and patterns in the evolution of vascular plants: macroevolutionary implications of a multilevel taxonomic analysis
2010
Cascales-Minana, B., Munoz-Bertomeu, J., Ros, R., Segura, J. 2010: Trends and patterns in the evolution of vascular plants: macroevolutionary implications of a multilevel taxonomic analysis. Lethaia, 10.1111/j.1502-3931.2009.00212.x Studying the macroevolutionary patterns of vascular plants from the Silurian to the present-day provides a global record of plant life history. Evolutionary rates (origination, extinction and diversification) for families, orders, classes and divisions were analysed, as was abundance and richness for 21 time intervals. An accumulative analysis, based on the total plant fossil record, the accumulated extinctions and relative diversity, was also carried out. The d…
Biodiversity dynamics and their driving factors during the Cretaceous diversification of Spatangoida (Echinoidea, Echinodermata)
2004
Abstract Variations in recorded diversity over time present a scrambled signal that is modulated by a large number of variables: the potential of particular life forms to generate evolutionary innovations, external constraints induced by the environment in its broad sense, the heterogeneity of the fossil record and the analytical artefacts due to sampling bias. A key question is how to characterise and quantify the separate input of any given factor in the overall diversity signal. This paper explores the structure of diversity data for spatangoid heart urchins and the sensitivity of recorded diversity to different factors of analytical bias (length of geological periods, proportion of pala…
What drives the disintegration of the loan origination value chain in the banking business
2015
Purpose - The purpose of this paper is to analyze the vertical disintegration of the bank loan origination value chain. This paper conducts a study on the credit information market from the perspective of the bank's decision to vertically disintegrate the loan origination value chain. The main aim is to identify the relevant drivers of the decision to vertically disintegrate the credit assessment phase in the lending business.Design/methodology/approach - Transaction cost economics and information asymmetry are the typical perspectives of analysis of the vertical scope of business value chains.Findings - This paper argues that in order to capture the drivers underlying the dynamic evolution…
Brokers in the Credit Market: An Examination of the Vertical Scope
2014
This paper analyzes the vertical disintegration of the bank loan origination value chain. The main aim is to identify the relevant drivers which cause the emergence of brokers in the credit market which lead to vertical disintegration of the credit origination value chain. Transaction cost economics is the typical perspective of analysis of the vertical scope of banking value chains. This paper argues that in order to capture the drivers underlying the dynamic evolution of the vertical scope of bank loan origination business models, the above perspectives must be combined and further integrated with a capabilities and resource based view and with a modularity perspective.
Origination and extinction patterns of mammals in three central Western Mediterranean islands from the Late Miocene to Quaternary
2008
Abstract An overview of the population histories of three insular realms (Gargano palaeo-archipelago, Sardinia–Maritime Tuscany palaeo-bioprovince and the Sicilian insular complex) during the Late Miocene and Quaternary are here presented. The complexity of biodiversity changes in the islands is analysed to propose an interpretation of origination and extinction patterns. The study highlighted several important aspects of insular faunas. Evolutionary radiations were found to contribute significantly only to the Gargano faunal diversity, likely because the area was an archipelago at the time. Another interesting result is that large and small mammals do not disperse and become extinct all at…