According to the modern synthesis, evolution is the gradual change of gene frequencies in a population. The MS is closely allied to adaptationist explanations of phenotypes, where organismic form and behavior is treated as previously selected for and owes its genesis to some remote past. However, some new theories of evolution broadly aligned with the extended evolutionary synthesis, in particular developmental plasticity theory and niche construction theory, foreground the fact that evolution is sometimes much more rapid than previously imagined, and (...) occurs through the active engagement of organisms accommodating and modifying their environments. This article describes how these contemporary theories reveal two interconnected sides of being an adaptive subject, a situated agent that modifies itself and its environment as it lives, and contributes to evolution in turn. MS and adaptationism have a generic logical structure that can be taught anywhere, but because developmental plasticity theory and niche construction theory point to an ontology that foregrounds the agency of the organism, they benefit from in situ exploration. I argue biology as a subject needs to adapt, and call for the renewed importance of field studies, outlining some elements of how such studies might be conceived. I close by considering how understanding organisms as adaptive subjects of evolution has important implications for sustainability education. (shrink)