The traditional, gene-centered view of the Modern Synthesis is loosing ground against a perspective that focuses on development as the pacemaker of evolutionary innovation (DevoEvo). These rising theories, arranged around the phenomenon of phenotypic plasticity, are much in need of further experimental grounding. The proposed work on pupfish of the genus Cyprinodon is an effort to fill this gap. These tiny fish have been described as beeing able to “survive almost everything“ (Soltz et al., 1978), and react with a high degree of phenotypic plasticty towards changing ecological conditions. Environmental induction (West-Eberhard, 2003), epigentic origination (Müller et al., 2005), and „neophenogenesis“ (Johnston et al., 1990) are potential mechanisms thought to underlie the origin of phenotypic novelty in changing environmental conditions. These concepts will be tested using closely related species of pupfish adapted to various kinds of extreme conditions. The empirical and experimental work of this project will focus on the “making of new species“ under artificial conditions (phenotypic engineering) and on fast evolving species in the laboratory of nature ( Feder et al., 2000). The comparative physiological and morphological approach will include the use of advanced quantitative tools such as Micro-CT (Weninger et al., 2006) and Digital Motion Imaging (Schwerte et al., 2000).