Invertebrate Phylum ANNELIDA (Segmented Worms)

Vocabulary Setae = tiny bristles projected from body to help move and dig Castings = dirt and waste as feces Gizzard = a muscular region of the digestive tract that breaks down food particles Crop = structure that stores soil

Characteristics A. Body shape = cylindrical with segments B. Color = pale red varying from dull pink to brown C. Size = a few centimeters D. Lifespan = few weeks to ten years

Characteristics E. Body = thick in the middle and tapers off at each end F. Senses = touch only G. Reproduction = hermaphrodites, but cannot reproduce with themselves

Locomotion A. Muscles a. Circular outer muscles allows the worm to grow longer and thinner b. Longitudinal inner muscle allows the worm to shrink and widen B. Setae a. Tiny hairs hook into the ground allowing worm to push forward

Digestion (Plays an important roll in making soil more fertile) A. Burrows and help bring oxygen to plant roots B Feed on soil and organic matter at the same time

Digestion C. Eliminates dirt and waste as feces called castings D. Gizzard grinds dirt and soil in the worm’s digestive tract E. Food is digested and absorbed by the blood after it goes through intestines

Other Annelids A. Leeches (mostly freshwater; can be found in moist soil) a. parasites of vertebrates (use jaws to drink blood from host) b. can be used in surgery to prevent clotting

Other Annelids C. Sand worm (found at tide level) a. eat small, animals b. have hard pointed jaw