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Full-Text Articles in Physical Sciences and Mathematics

Parasitism, The Diversity Of Life, And Paleoparasitology, Adauto Araújo, Ana M. Jansen, Françoise Bouchet, Karl J. Reinhard, Luiz F. Ferreira Feb 2003

Parasitism, The Diversity Of Life, And Paleoparasitology, Adauto Araújo, Ana M. Jansen, Françoise Bouchet, Karl J. Reinhard, Luiz F. Ferreira

School of Natural Resources: Faculty Publications

The parasite-host-environment system is dynamic, with several points of equilibrium. This makes it difficult to trace the thresholds between benefit and damage, and therefore, the definitions of commensalism, mutualism, and symbiosis become worthless. Therefore, the same concept of parasitism may encompass commensalism, mutualism, and symbiosis. Parasitism is essential for life. Life emerged as a consequence of parasitism at the molecular level, and intracellular parasitism created evolutive events that allowed species to diversify. An ecological and evolutive approach to the study of parasitism is presented here. Studies of the origin and evolution of parasitism have new perspectives with the development of …


Evolution Of Chemical Contaminant And Toxicology Studies, Part 2- Case Studies Of Selenium And Arsenic, Glennys O'Brien, Dianne Jolley, Robert John Morrison Jan 2003

Evolution Of Chemical Contaminant And Toxicology Studies, Part 2- Case Studies Of Selenium And Arsenic, Glennys O'Brien, Dianne Jolley, Robert John Morrison

Faculty of Science - Papers (Archive)

As the second of a two part series discussing the evolution of the field of environmental toxicology, this paper presents two case studies: selenium and arsenic. Developments over several decades in the understanding of the behaviour of arsenic and selenium in different chemical forms in various compartments of the environment are discussed. Selenium was initially thought to be toxic, but later investigations showed it to be an essential micronutrient with a variety of biochemical functions, and, importantly, that there is a very narrow gap between the essential and the toxic body burden. Arsenic, on the other hand, has not yet …