BIO153H5 Chapter Notes - Chapter 34: Pharyngeal Slit, Filter Feeder, Craniate
Document Summary
Echinodermata (sea stars, sea urchents, etc: basal deuterosome, sister group to chordates, larvae is bilaterally symmetrical, but adult is 5 part symmetrical similar to radial. Chordata: bilaterally symmetrical, all contain 4 key characteristics, notochord, present in all chordates during embryonic development, some adults may retain it or it will be greatly reduced, cartilaginous rod that would produce structural support. In humans it is reduced, forms part between vertebral column: somites found along site in embryonic development, develops as muscle segments, nerve cord, embryonic feature, develops into spinal cord and brain, located dorsal to notochord, pharyngeal slits/clefts. Cephalochordata (lancelet): basal chordate, displays 4 unique characteristic into adulthood, pharyngeal slit-food intake (marine suspension feeder) Urochordata (tunicate): displays 4 characteristics in larval stage, loses some in adulthood (marine suspension feeder, more closely related to other chordates than cephalochordates, 9 hox genes lost 4 when branching off.
