Phylum Annelida (Segmented Worms)

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Phylum Annelida(Segmented Worms)

• 15,000 Annelid species
• Bilaterally symmetrical coelomates
• Coelomes divided into partitions by septa
• Inhabit marine, fresh water, moist environments
• Has complex digestive system
• Has closed circulatory system
• Epidermis is primary gas exchange organ
• Are hermaphroditic
• Reproduce sexually by cross fertilization
• Reproduce asexually through regeneration
• 3 Classes

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Class Oligochaeta

• Include earthworms
• Extracts nutrients from soils
• Extremely beneficial to farming as they enrich
  and aerate soils

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The Earthworm
Giant Earthworm Amazon Basin
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Class Polychaeta

• Very similar to oligochaeta
• Most are marine
• Have paddle or ridge-like extensions on segments
  called parapodia
• Aid in gas exchange and locomotion

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Lugworm
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Class Hirudinea (leeches)

• Most inhabit fresh water, or moist terrestrial
  environments
• Feed on small invertebrates or are parasitic
• Have significant medicinal value in treating
  bruising, and as a source of Pharmaceuticals

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The Leech