As vertebrates evolved, the increasingly complex structure of the brain conferred increasingly complex function, especially apparent in the . See Concept 49.3 (Page) View Available Hint(s) As vertebrates evolved, the increasingly complex structure of the brain conferred increasingly complex function, especially apparent in the . See Concept 49.3 (Page) cerebral cortex, which is greatly expanded in humans, other primates, and cetaceans brainstem, which in most vertebrates, controls homeostasis and basic bodily function medulla oblongata, which controls automatic functions forebrain, which is a small brain region that arises early in development sleep-wake cycles of birds and mammals