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PHYLUM ANNELIDA – segmented worms. Biology 112. Annelids. Representative species: common earthworm. Longest Earthworm found in Australia 12 feet long and thick as a coke can. Annelids. Have a coelom – fluid filled body cavity surrounded by a mesoderm (room for organs)
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PHYLUM ANNELIDA – segmented worms Biology 112
Annelids • Representative species: common earthworm
Longest Earthworm found in Australia • 12 feet long and thick as a coke can
Annelids • Have a coelom – fluid filled body cavity surrounded by a mesoderm (room for organs) • Have a peritoneum (membrane in the coelom in which all organs are attached) • Have 2 sets of muscle tissue. • 1. body wall muscles – to move the worm and • 2. digestive system muscles to move food through the system
Segmented Worms • Tube within a tube digestive tract with food passing through mouth to anus
Class Oligochaeta: Earthworms ``It may be doubted whether there are any other animals which have played so important a part in the history of the world as the earthworm.`` -Charles Darwin, 1881 http://mypeoplepc.com/members/arbra/bbb/id19.html
Class Oligochaeta: Earthworms • 2500 species • Many more cell layers than flat and round worms • Have blood to carry gases to and from body tissues (circulation) • Blood in earthworms contains a red protein hemoglobin (just like in us!) • Have 5 hearts near the anterior end
Class Oligochaeta cont… • More complex digestive system than other worm phyla • They consume dirt (food and sand particles) via mouth, pharynx, esophagus and then stores it in the crop. • After storage, food moves to the gizzard to be ground down, then to the intestine for digestion and absorption into the blood stream. • Undigested food moves out the anus
Class Oligochaeta cont… • Setae are bristles that aid in movement; each segment has 4 setae (except first and last ones) • Complex NS • Reproduce sexually • Hermaphrodites
Other ANNELIDS • Class Hirudinea – leeches (blood sucking parasites)
Class Polychaeta – marine worms Family Nereididae Planktonic Polychaete Worm http://beyond.australianmuseum.net.au/holoplankton/holoplankton05.htm
Terebellid Worm Larva (polychaete) http://beyond.australianmuseum.net.au/zooplankton/zooplankton01.htm
Worm Grunting/Charming http://www.youtube.com/watch?v=VjRxUVLxdYI http://www.youtube.com/watch?v=IGviTYCFksE
Summary of Earthworm • Movement • no skeleton; two layers of muscle • moves by setae; 4 per segment • Digestion • has true coelem • order is as follows mouth, pharynx, esophagus, crop, gizzard, anus • Nervous system • simple brain, nerve cord • Circulation • 5 hearts and blood vessels • Respiration • O2 in the skin; CO2 out the skin • Reproduction • Sexually; male and female parts (hermaphroditic) • Excretion • waste through nephridia that lead to pores in the skin • Symmetry – bilateral symmetry
Pictures for Lab • http://kentsimmons.uwinnipeg.ca/16cm05/16labman05/lb6pg2.htm • Practice Quiz - Online • http://www.rcs.rome.ga.us/hargett/biology/worms/wrmdia.htm