  A straightforward formalism to evaluate the impact of Type Ia Supernovae on
large scale astrophysical issues is presented, together with analytical
formulations for the SNIa rate following an instantaneous burst of Star
Formation, for both single and double degenrates SNIa progenitors' models. Some
applications of the parametrized formalism are illustrated. In particular, it
is shown that the current SNIa rates measured in early and late type galaxies,
as well as the Fe Mass-to-Light ratio in clusters of galaxies, favour the
double degenerate model.
