We show that the multiphase chemical evolution model reproduces the correlations obtained along the spiral sequence, dwarf galaxies included. However the apparent spatial chemical uniformity observed in some irregular galaxies cannot be reproduced with it. An evolutionary model has been developed and tested to explain flat gradients. Preliminary results, obtained with a new code including supernova winds and radial flows, suggest that radial flows are probably responsably for this uniformity

5 pages,5 figures, to be published in the proceedings of the ESO "Chemical Evolution from Zero to High Redshift" workshop, Eds. M.Rosa and J.R. Walsh (Springer-Verlag)