  The decrease, since z=1, of the rest-frame UV luminosity density is related
to global changes in morphology, color and emission lines properties of
galaxies. This is apparently followed by a similar decrease of the rest-frameIR
luminosity density.
  I discuss the relative contribution from the different galaxy morphological
types to the observed evolution. The main contributors are compact galaxies
observed in large number at optical wavelengths, and the sparse population of
extincted & powerful starbursts observed by ISO. This latter population is made
of large and massive galaxies mostly found in interacting systems, some of
which could be leading to the formation of massive ellipticals at z< 1.
