User:Jtwsaddress42/Projects/Project 4/Sections/Chapter 6/The problems of amniote and mammalian evolution - Reorganizing the organism for land, air, and social-engagement

Many of the most important modifications of the vertebrate body plan in mammals concerns the adaption to land. There are several key features of significant importance:


 * transformation of the swim bladder, which is off the main circulatory tract of the pharyngeal arch system that oxygenates blood flow to the brain, into the lung.
 * remodeling the two chamber heart into the four chamber heart so as to establish the cardiopulmonary loop and reestablish fully oxygenated blood flow to the brain, marking the onset of endothermy and a relatively continuous real-time foraging and exploration strategy.
 * the myelinated division of the parasympathetic nervous system
 * remodeling the pharyngeal arch nerve components into the cranial nerves via the myelinated parasympathetic.
 * the emergence of the neocortex and the thalamocortical system from the olfactory cortex.
 * bringing the limb girdles from their ancestral position as fins, to a position that brings them under the body carriage in early mammals.
 * adapting chemosensory and olfactory senses to air from their ancestral aquatic adaptions.
 * remodeling the lateral line for sensing water pressure into the auditory system for sensing air pressure.
 * remodeling vestibular, olfactory, visual, and newly emergent auditory into the head-neck system.
 * remodeling the pharyngeal arch cartilages, and muscle groups, to become part of the social engagement system linking body posture, head-neck orienting postures, and facial expressions together with vocalizations that are linked to species specific auditory enhancement and entrainment mechanisms.