BIO 1130 Lecture Notes - Lecture 13: Cnidocyte, Mecha, Axial Skeleton

• School: University of Ottawa
• Department: Biology
• Course: BIO 1130
• Professor: Jon Houseman

Document Summary

Where we are at started to work our way down the protostome linneage: ecdyzozoa nametode, crustacea, lophotroazoa mullosc and annelids, platyzoa. Platyzoa a pseudoceolome is(cid:374)"t really a phyloge(cid:374)etic e(cid:448)e(cid:374)t it o(cid:374)ly occurs duri(cid:374)g (cid:373)i(cid:374)iaturizatio(cid:374). Platyhelmeinthes- usually associated this group with loss of te ceolome. We thought that the aceolomate condition sat at the bottom of the dladogram but what the biology tells us is that it is a derived condition. In addition: the presence of an incomplete gut. We have talked about the advantage of the tub within a tube. Going backwards: on the digestive tract going fromcomplete to incomplete gut and then from ceolomate to aceolomate. Anatomical - all mesoderm arranged around the gut. There are still longituninal muscle and circular muscle: organiszation; outer circular muscle; longitudinal; dorsal ventral muscle. They ensure that tissues are close to the gut. sti(cid:374)gi(cid:374)g (cid:272)ells do(cid:374)"t fire they migrate from the digestive tracte to the outer body wall.