BIO1011 Lecture Notes - Lecture 17: Chordate, Notochord, Endoskeleton
6 Aug 2018
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Lecture 18: recognise the characteristic features of the chordates and how they changed in the evolution of the different groups. Notochord: is a longitudinal, flexible rod located between the digestive tube and the nerve cord. Provides skeletal support throughout the life span of the individual. Provides a firm but flexible structure against which muscles work during swimming. Develops from a plate of ectoderm that rolls into a neural tube located dorsal to the notochord. Hollow nerve cord is unique to chordates. In chordate embryo, it develops into the central nervous system such as brain and spinal cord. Allows water entering mouth to exit the body without passing through the entire digestive system. Functions as suspension feeding devices in any invertebrate chordat\][puy6f es. In vertebrates, these slits and the pharyngeal arches that support them have been modified for gas exchange and are called gills. Contains skeletal elements and muscles and it helps propel many aquatic species in water.
