BIOL 1115 Chapter Notes -Diploblasty, Chelicerae, Fish Fin
11 Feb 2014
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Phylum annelida (protostome- first opening is the mouth) (eucoelomate - a true coelomate) Septa - segmented partitions that divide the internal, fluid filled coelom (hydrostatic skeleton) Lost body segment => other segments can take over functions. Flexibility and locomotion (peristalsis -> wavelike movements) Setae/chetae(chitin)- bristles that help the organism move: polychaetes. Have prostomium, peristomium, parapodia, and many setae (confined within burrows) and errant polychaetes (actively mobile) Parapodia - paired fleshy appendages (for locomotion and respiration) Prostomium - region above the mouth [ex. Peristomium - region around the mouth (contains mouth) Atoke - the anterior sexless part of certain polychaete worms. : modified reproductive segment of worm (posterior), swarming is simultaneous release of all eggs and sperm. Symbiotic relationship with chemosynthetic bacteria - uses organism waste to produce organic material (food) Trophosome worms -> worms dependent upon bacteria for food. Setae protrude in pairs from surface of body. Food drawn into mouth by muscular pharynx.
