BIO 2135 Lecture Notes - Lecture 5: Protractor, Pylorus, Gastric Glands
12 Oct 2017
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Found at the very base of the group. Not necessarily part of the deuterostome lineage. Because the unique characteristics of deuterostomes got all mixed up often what you actually see in deuterostomes don"t match these autapomorphies. The main de ning characteristic is and rests on the fate of the blastopore. Lophophorates also have a tripartite enterocoely coelom. Not a monophyletic event (it didn"t just happen once, it happen again in a group later on too) Straight tube gut leading to an anus on the other side. Once direct development occurs this larvae disappears. Plates of calcareous material (bony tissue) and it is perforated = stereom spicules, the plates are connected to each other by mutable connective tissue. Sea urchins really use the stiff mutable connective tissue to squeeze into protective. Developed an elaborate stalk that listed them off the ground. Tube feet would capture foot that fell through the water column. Hence they caught food before it hit the bottom.
