Galaxy Evolution with Alma

The submillimeter and millimeter domains are privileged for the exploration of galaxies at high redshift, because of the negative K-correction: the peak of the dust emission at 60-100 microns is red-shifted in these domains. Already blind surveys in blank fields with today instrumentation have discovered in the continuum of the order of one object per square arcmin, with large limitations due to confusion. In the molecular lines, the K-correction is not so favorable, and it has been until now difficult to detect the objects, except when they are starbursting monsters, or gravitationally lensed (about a dozen galaxies have been detected). ALMA will bring more than one order of magnitude improvement, and will not be affected by confusion. Normal star-forming objects will be detected, and in particular those enshrouded in dust, so the instrument will be complementary to the optical ones, such as NGST or ELTs.