Individual mortality is the result of intrinsic (e.g., senescence and morbidity) or extrinsic factors (e.g., environmental stochasticity and natural disasters). For populations, mortality can be an important regulatory mechanism when deaths resulting from biotic (usually density dependent) or abiotic (usually density independent) factors limit population growth. Density-dependent and density-independent mortality factors were first described by Howard and Fiske in 1911, and were referred to as 'facultative mortality' and 'catastrophic mortality', respectively. A central issue in understanding population dynamics is the attempt to separate and identify the roles of density-dependent and density-independent processes in determining the growth, predictability, and variability of population abundances. However, because observations of death in nature are often difficult to pin down to a single cause, it has been a challenge to isolate their separate effects.
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This work on 2012 will attempt to note them allfrom the concepts andinvolvement by the authors of the Bible and its interpreters and theprophecies depicted in both the Hopi petroglyphs and the Mayan calendarto the prophetic uttering of such psychics, mediums, and prophets asNostradamus, Madame Blavatsky, Edgar Cayce, and Jean Dixon.