  The recent determination of the baryon-to-photon ratio from WMAP data by
Spergel et al. (2003) allows one to fix with unprecedented precision the
primordial abundances of the light elements D, 3He, 4He and 7Li in the
framework of the standard model of big bang nucleosynthesis. We adopt these
primordial abundances and discuss the implications for Galactic chemical
evolution, stellar evolution and nucleosynthesis of the light elements. The
model predictions on D, 3He and 4He are in excellent agreement with the
available data, while a significant depletion of 7Li in low-metallicity stars
is required to reproduce the Spite plateau.
