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Phylum Annelida. The segmented worms. ZOOLOGY Southern Boone County High School Bill Palmer. “annelus” - little ring. TYPICAL ANNELIDS. Segmented worms Earthworms Leeches Bristleworms. ANNELIDS-Characteristics. 12,000 species Tube-within-a-tube Structure Bilateral Symmetry
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Phylum Annelida The segmented worms ZOOLOGY Southern Boone County High School Bill Palmer “annelus” - little ring
TYPICAL ANNELIDS • Segmented worms • Earthworms • Leeches • Bristleworms
ANNELIDS-Characteristics • 12,000 species • Tube-within-a-tube Structure • Bilateral Symmetry • Mouth and Anus • Setae (tiny bristles) • Help annelids to move • Terrestrial, Marine, and Aquatic
ANNELIDS-Characteristics • All have segments (Like stacked donuts)
General characteristics • segmentedbody • each segment has paired • excretory nephridia, nerves • closed circulatory system • nervous system with double • ventral nerve cord- • ganglia for brain
respire through skin or with gills • body wall with longitudinal and • circular muscle • setae/ bristles in skin • used for locomotion
3 variations in setae structure
3 classes of Annelida Class Polychaeta – mostly marine fanworms, bristle worms, tube worms Class Oligochaeta - earthworms Class Hirudinea - leeches
Class Polychaeta Marine tubeworms, fanworms and bristle worms Most primitive class- have well developed anterior end (head)
WOW ! lots of variety and color in marine species
Setae on parapodia Marine polycheate – bristle worm
Bristle worms Fleshy parapodia
Ciliated feathery tentacles for feeding tube Marine fanworm
Feather duster worms ( Polychaetes) Filter feeder
Giant tube worms ( 4 ft long) in ocean thermal vents
Calcareous (limestone) tubes of marine annelids
Earthworms are important Food chains Aerate soil
Bloodworm - Marine species Lives in mud at ocean bottom Great fishing bait!
Polychaeta worm larva – pelagic ( planktonic ) Branching nerves
Class Hirudinea the leeches parasites
Segmentation evident Suction disk Leech
Leech 3 pairs of eyes
Class Oligochaete The earthworms plus some freshwater species
Flatworm meets Annelid Crime scene Scotland
Fossil Polychaete worm Bristles and segmentation evident
Spriggina fossil Precambrian segmented invertebrate Segmented body ( metamerism )
Trochophore larva- typical of some annelids Mollusca phylum also has trochophore Larvae… suggesting related evolution
Wrap-ups • How many species of annelida are there? • What are the characteristics of annelida? • What are the three classes of annelida? • List three reasons why earthworms are important. • How are leeches used in medicine?