BIO 2135 Study Guide - Final Guide: Coelom, Aortic Arches, Annelid

• School: University of Ottawa
• Department: Biology
• Course: BIO 2135
• Professor: Jon Houseman

Document Summary

2: here we go one step beyond the molluscs. We have the blastopore becoming the mouth, spiral cleavage, lophotrochozoa and the organisms with the trochophore larva: just before hitting the molluscs and before the annelids. The characteristic of the schizocoel (mesoderm forms by splitting of the block in the embryo giving a coelomic space and in this face there is the metanephridia that ilters the luid in there); There is also the dorsal heart inside the pericardial cavity: the mollusc then took these characteristic and underwent adapted radiation. So every single segment(metamere) is identical to the one on either side of it down the length of the body. This is a strategy for enlarging the size of an organism: metamerism is based on mesoderm. So it is the mesodermal miscle blocks that are being arrange metamerically. A protostomium that is in front of it-this s where the brain and cephalization occur and a segment that houses the anus behind.