e·co·phys·i·ol·o·gy 
(ē′kō-fĭz′ē-ŏlə-jē, ĕk′ō-)
(ē′kō-fĭz′ē-ŏlə-jē, ĕk′ō-)n.
The study of the interrelationship between an organism's physical functioning and its environment.
e′co·phys′i·o·logi·cal (-ə-lŏjĭ-kəl) adj.
e′co·phys′i·olo·gist (-ŏlə-jĭst) n.