Chapter 34/35 : Worms

I. Body Positions Dorsal (Back) Posterior (Rear) Anterior (Head) Ventral (Belly) *Bilateral symmetry – cut down middle and both halves the same

II. Phylum  A. Platyhelminthes – flat worm 1.) Planarian – aquatic 2 eyespots (sense light) Hermaphrodite (male & female) Regenerate – regrow missing parts Scavenger

II. Phylum : Platyhelminthes ○ 2.) Fluke Parasite Thick cuticle & suckers Hermaphrodite Common in Orient, Cuba Life cycle with a snail

II. Phylum : Platyhelminthes ○3○3.) Tapeworm Passes through feces eaten by pigs or cows Causes organisms to lose nutrients, weight, weakness Head contains suckers scolex Proglottid – each contains sex organs (hermaphrodite)

II. Phylum : Nematoda  B. Nematoda – round worm 1.) Ascaris Pigs, horses, humans through dirt or contaminated food 2.) Hookworms – bore into feet Common in south and tropics Cause anemia and slows growth

II. Phylum: Nematoda 3.) Trichina – found in contaminated pork 4.) Pin Worms – found in soil  C. Phylum : Annelida – segmented worms, earthworm, leech

II. Phylum : Annelida ○ 1.) Characteristics of Annelida Soil or no soil Not parasite Called tube within a tube Fertilize and aerate soil Hermaphrodites

II. Phylum: Annelida ○ 2.) External Parts Prostomium – lip Clitellum – band of reproduction segments – Setae – bristles on ventral surface used for clinging

II. Phylum : Annelida ○ 3.) Digestive System Pharynx – sucks soil To Esophagus then to crop (stores food) To Gizzard (grinds food) Through Intestine and out anus

II. Phylum : Annelida ○ 4.) Circulatory System Dorsal Blood Vessel – blood flows through anterior end Ventral Blood Vessel – blood from posterior end Aortic Arches – 5 pairs-like heart – pumps blood Closed Circulatory System – blood remains in tubes

II. Phylum : Annelida ○ 5.) Respiration & Excercretion Absorb O 2 and releases CO 2 through skin. Mucus from skin helps moisten air for easier respiration. Also slides through soil better. Waste excreted by anus and nephridia (holes on segments that act like kidneys- excrete liquid waste)

II. Phylum : Annelida ○ 6.) Nervous System Ventral nerve cord (white) Sensitive to sound and light Brain Tissue

II. Phylum : Annelida ○ 7.) Reproduction Hermaphrodite but eggs must be fertilized by another worm *Sperm made in testes and stored in seminal vessicles. Received sperm is stored in the Seminal Recepticles.

* During Reproduction *  Worms line up upside-down.  Eggs Released into slime ring around clitellum.  Sperm released to fertilize eggs.  Slime ring slips off to form protective cocoon for developing young.