  The paper presents a recursive function able to mimic demographic mortality
curves. This function is not a fitting algorithm and depends only from one
parameter, that has a precise meaning in a cellular automaton model. This model
is also presented. For the function definition, the Fermi statistics method of
calculation has been used, resulting in similarities with known statistical
distribution curves. A continuous representation of the recursive equations is
also provided. Implications with life span and more general life cycle concepts
are outlined.
