Density Independent versus Density Dependent Mortality

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.

The Basic Survival Guide

The Basic Survival Guide

Disasters: Why No ones Really 100 Safe. This is common knowledgethat disaster is everywhere. Its in the streets, its inside your campuses, and it can even be found inside your home. The question is not whether we are safe because no one is really THAT secure anymore but whether we can do something to lessen the odds of ever becoming a victim.

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