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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The Extent of Contemporary Species Loss and the Effects of Local Extinction in Spatial Population Networks

Lamkin, Megan K. 13 September 2016 (has links)
No description available.
2

Paleobiological assessment of controls underlying long-term diversity dynamics

Cárdenas, Andrés L. 01 January 2012 (has links)
Deciphering the factors underlying both long-term patterns of diversity and taxonomic turnover rates (i.e., extinction, and origination) has been one of Paleobiology's major foci for the past three decades. The importance of documenting these components is that they will expand our ability to interpret and model the evolutionary processes underlying those trends, highlight the evolutionary impact of historical events, and contribute to the formulation of robust predictions about the future of global diversity in response to the current anthropologically driven environmental changes. Accordingly, the first part of this study examines the possible occurrence of global marine evolutionary environmental controls into a `deep-time' perspective, using a statistical time-series approach between the most recent Phanerozoic global marine generic origination rates with coeval mean global marine geochemical and geological signatures of environmental proxies. After this examination, significant positive correlations were found between changes in origination rates and global mean signatures of 87Sr/86Sr and δ34S, as well as a significant negative correlation between variability in both origination rates and eustatic sea level. They suggest that over secular timescales, nutrient availability, as controlled by continental weathering, phosphorus recycling, and the relative extent of shelf exposure, is an important regulator of genus-level origination in the marine realm, with periods of increased nutrient availability associated with higher origination rates.

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