Redshift evolution of for MS galaxies and starbursts. At z ~ 0 we use the average value derived from the samples of Leroy et al. (2011) for the spirals (gray circle). Black squares represent individually detected normal star-forming galaxies at z ~ 0.5–1.5 (Daddi et al. 2010; Magdis et al. 2012a), while the black triangles denote lensed galaxies at z ~ 1.4–3.1 (Saintonge et al. 2013). The best fit to the normal galaxies yields a relation of (solid line). In addition to GN20, GN20.2a, and GN20.2b in our sample at z = 4.05, we also plot starbursts (grey and color stars) from the literature as follows: z ~ 0 ULIRGs (Downes & Solomon 1998); SMM J2135-0102 at z = 2.325 (Swinbank et al. 2010); HSLW-01 at z = 2.957 (Riechers et al. 2011); ID 141 at z = 4.243 (Cox et al. 2011); LESS J033229.4-275619 at z = 4.760 (Coppin et al. 2010; Gilli et al. 2014); HDF 850.1 at z = 5.183 (Walter et al. 2012); AzTEC-3 at z = 5.298 (Capak et al. 2011; Riechers et al. 2010a; Dwek et al. 2011); HFLS3 at z = 6.34 (Riechers et al. 2013). The best fit to the starburst galaxies gives a relation of (dashed line).