The mechanism works by allowing multiple small genetic variations to accumulate and then expose themselves when that organism is under environmental stress.
All organisms make heat shock proteins, also known as chaperones, in response to high temperatures.
Once this happens, the misshaped protein can no longer function, and regular cellular metabolism cannot proceed. Hsp 90s charges are special. They are proteins called signal transducers, which regulate development and cell differentiation. Hsp 90 keeps them poised and ready for action. Signal transducers control morphological development.