BISC 121Lg Chapter Notes - Chapter 34: Pharyngeal Slit, Dorsal Nerve Cord, Axial Skeleton
Document Summary
Chapter 34: amphibians, reptiles and birds, and mammals are modern terrestrial vertebrates. Chordates- bilaterian deuterostomes, vertebrates are in this phylum: key characteristics: notochord, dorsal hollow nerve cord, pharyngeal slits/clefts, and muscular post-anal tail, notochords- longitudinal, flexible rode between the digestive tube and nerve cord. Forms part of gelatinous disks between vertebrae in human. In most vertebrates a more flexible and jointed skeleton forms around it: dorsal nerve cord- dorsal to notochord, develops from ectoderm. Develops into the brain and spinal cord: pharyngeal slits/clefts- grooves that develop into slits that open into the pharynx to allow water in the mouth to exit the body. Develop into ears in tetrapods: muscular post-anal tail- has skeletal elements and helps move through water. Lancelets- most basal living chordates, bladelike shape: larvae feed on plankton by swimming and sinking (suspension feeders, lives in sand with anterior end exposed, use cilia and pharyngeal slits to feed, can swim.
