 The relationship between development and evolution has recently become a lively debated topic among philosophers and biologists. This interest has been increasingly stirred through at least four developments since the 1990s: First, through new findings of the molecular genetic mechanisms underlying the development and evolution of all morphological forms in multicellular organisms. This discovery eventually led to the foundation of the new field of evolutionary developmental biology (evo-devo). Second, the ability to rapidly sequence genes and genomes allowed genetic comparisons to be made between species. Prior to this, evolutionary genetics was confined to allelic differences within a species. Third, new discoveries of environmentally sensitive channels of extra-genetic transmission of information between organisms (e.g., epigenetic inheritance and transmission of microbiota) led to attempts to more closely connect development and inheritance, and, as a consequence, evolution. Fourth, the behavioral patterns developed by organisms are increasingly discussed not only as effects of adaptive processes, but as starting point of evolutionary trajectories. This includes hypotheses conceptualizing organisms as agents that co-modify the selective pressures effecting them (and other species). 