Abstract: The trend for highly star forming (SF) galaxies to show, on average, higher levels of obscuration compared to low star formation rate (SFR) systems is becoming more well-established. Some observational results exploring this effect, and its implications for the evolution in the global space density of SFR will be presented. This SFR history is used to constrain models of evolution for SF galaxies, and the connection with gas evolution is explored through the properties of damped Lyman alpha (DLA) systems.