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Phylum- Annelida. http://kentsimmons.uwinnipeg.ca/16cm05/16labman05/lb6pg2_files/earthworm2.bmp. Phylum Annelida. This phylum consists of the segmented worms The members of this phylum live in three different environments: Freshwater Saltwater On land
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Phylum- Annelida http://kentsimmons.uwinnipeg.ca/16cm05/16labman05/lb6pg2_files/earthworm2.bmp
Phylum Annelida • This phylum consists of the segmented worms • The members of this phylum live in three different environments: • Freshwater • Saltwater • On land • This phylum consists of three classes: • Class Oligochaeta • Class Polychaeta • Class Hirudinea
Term “Annelid” • The term annelid means little rings • This is referring to the many body segments found in members of this phylum
All (approximately 15,000) members of this phyla have: • Bilateral Symmetry • A true coelom • Segmentation • All three germ layers • Endoderm • Ectoderm • Mesoderm
Coelom and the 3 Germ Layers: Coelom: a fluid filled cavity within the mesoderm
Evolutionary more advanced • The presence of a true coelom, three germ layers and all organ systems makes the annelids the most advanced of all the worm phyla
Setae or parapodia: • These structures are found on the outside of each body segment • The presence or absence of parapodia groups the annelids into 3 classes; also, the number of setae per segment is used for this function