Tracing the ancestry of galaxies on the land of our ancestors

I review the major surveys of high redshift galaxies observed using integral field spectroscopy techniques in the visible and in the infrared. The comparison of various samples has to be done with care since they have different properties linked to their parent samples, their selection cri-teria and the methods used to study them. I present the various kinematic types of galaxies that are identified within these samples (rotators, mergers, etc.) and summarize the discussions on the mass assembly processes at various redshifts deduced from these classifications: at interme-diate redshift (z ∼ 0.6) merger may be the main mass assembly process whereas the role of cold gas accretion along cosmic web filaments may increase with redshift. The baryonic Tully-Fisher relation is also discussed. This relation seems to be already in place 3 Gyr after the Big-Bang and is then evolving until the present day. This evolution is interpreted as an increase of the stellar mass content of dark matter haloes of a given mass. The discovery of positive abundance gradients in MASSIV and LSD/AMAZE samples is highlighted. At z ∼ 3 this discovery might be linked to cold gas accretion along cosmic filaments toward the centre whereas at lower redshift (z ∼ 1.3), this may be mainly due to accretion of gas from outer reservoirs toward the centre via tidal tails due to interactions