Invertebrate Phylum

ANNELIDA(Segmented Worms)

VocabularySetae = 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

CharacteristicsA. 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

CharacteristicsE. Body = thick in the middle and

tapers off at each end

F. Senses = touch only

G. Reproduction = hermaphrodites, but cannot reproduce with themselves

LocomotionA. 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

DigestionC. 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 AnnelidsA. 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