Invertebrates 2 flatworms, molluscs & annelids

Some can regenerate segments invertebrates 2

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Some can regenerate segments
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Invertebrates -2: Platyhelminthes, Mollusca & Annelida Page 8 of 9 Immature sperm from testes mature in seminal vesicles (d) Nitrogenous wastes are excreted by metanephridia (e) Gas exchange occurs across the body, but there is a closed circukatory system (f) Earthworms have a well developed nervous system (i) Cerebral ganglia (ii) Subpharyngeal ganglion (iii) Ventral nerve cord (g) Reproduction A Copulation - Ventral surfaces together (held by mucous) - Mature sperm pass down sperm duct to genital pore & to seminal receptacle of mate. - Cocoon produced from citellum B & C - Worms separate & cocoon moves forward & picks up eggs & sperm D - Cocoon slips off anterior end E & F – Embryogenesis & young
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Invertebrates -2: Platyhelminthes, Mollusca & Annelida Page 9 of 9 3. Polychaetes (Class Polychaeta) - Sedentary, tube dwellers & free living (a) Parapodia for locomotion & respiration (as gills) (b) Well developed head with specialized senses 4. Leeches (Class Hirudinea) - Predators & scavengers - Reduced coelom & segmentation - Flattened - Suckers at either end
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  • Spring '10
  • Dr.DavidCreasey
  • Biology, Annelida, Annelid, Ventral nerve cord, Phylum Platyhelminthes, Platyhelminthes

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