The BzK diagram for galaxies at z < 1.4. The galaxy population is split into two groups: red points for passive galaxies, and blue points for star-forming galaxies (separated using rest-frame M_NUV − M_r colours). Only objects with K_s < 22 and a photometric redshift of z < 1.4 are shown. The black dashed lines show the cuts used by Daddi et al. (2004) to select z > 1.4 galaxies and stars, whilst the solid black line shows the model track for a passively evolving elliptical galaxy from z = 1.5 to z = 0. The filled black circles on this line are at intervals of Δz = 0.25, beginning at z = 0.25 and finishing at z = 1.5.