  We present a study of the evolution of late-type field dwarfs over the last ~
1.9 Gyr, based on HST ACS observations carried out as part of the GEMS survey.
This study is amongst the first to probe the evolution of dwarfs over such a
large timescale. The comparison of structural properties, particularly size and
scale length, indicates that the dwarfs in the redshift range z ~ 0.01 to 0.15
(look-back times up to 1.9 Gyr) are more extended than local dwarfs. We argue
that this difference is due to the star formation activity becoming more
centrally concentrated in late-type dwarfs over the last ~ 1.9 Gyr. We discuss
several possible causes for this evolution. We also find a lack of blue compact
dwarfs in the GEMS sample and interpret this as indicative of the fact that
strong, centrally concentrated star formation is a feature of evolved dwarfs
that are entering their final stages of evolution.
