coadaptation n.

in Latin, the form of com- "together, with" in compounds with stems beginning in vowels, h-, and gn-; see com-. Taken in English from 17c. as a living prefix meaning "together, mutually, in common," and used promiscuously with native words (co-worker) and Latin-derived words not beginning with vowels (codependent), including some already having it (co-conspirator).

c. 1600, "action of adapting (something to something else)," from French adaptation, from Late Latin adaptationem (nominative adaptatio), noun of action from past-participle stem of adaptare "to adjust," from ad "to" (see ad-) + aptare "to join," from aptus "fitted" (see apt).

The meaning "condition of being adapted, state of being fitted to circumstances or relations" is from 1670s. The sense of "modification of a thing to suit new conditions" is from 1790. The biological sense of "variations in a living thing to suit changed conditions" is by 1859, in Darwin's writings.