 The consequences of this tension for the intersection of development and evolution are two-fold. First, the most powerful experimental systems for studying development are set up to minimize variation that may be critical to comprehending how evolutionary processes occur in nature. Second, if evolutionary investigations revolve around a character that was assessed for typicality to underwrite the temporal partitions that we call stages, then much of the variation in this character was conceptually removed as a part of rendering the model organism experimentally  tractable.[21]