A phenomenological approach to the evolution of galaxies

Increasingly good statistical data on the galaxy population at high and low redshift enable the development of new phenomenological approaches to galaxy evolution based on application of the simplest continuity equations. This has given new insights into the different ways in which star-formation in galaxies is quenched, the role of merging in the population, and into the control of star-formation in star-forming galaxies and the links between this and chemical evolution, in particular the existence of SFR as a second parameter in the mass-metallicity relation. The continuity approach provides a self-consistent view of the evolving population and exposes linkages between different aspects of galaxy evolution.