FIGURE 1.

Hypothetical outcomes involving phenotype switching scenarios following exposure to adverse environments during critical windows in development. Scenario A shows the conventional, highly discussed condition of irreversible switching of phenotype induced by an environmental stressor during the critical window. Scenario B depicts a far less frequently studied situation of phenotypic switching initiated during a critical window that, in fact, is reversible to varying degrees. Scenario C indicates that there may be complete reversibility of phenotypic modifications occurring at varying rates during subsequent development. The extent and rate of phenotype reversal may relate to the extent of the difference between the altered and normal (typical) juvenile/adult phenotypes. Importantly, either a single trait might show different degrees of reversibility, or multiple traits could show a range of degrees of reversal to the normal phenotype.