WORMS

Flatworms Phylum: Platyhelminthes Bilateral symmetry Cephalization Acoelomates-without colelom

Speckled Flatworm Clings onto lower rocks. Eats amphipods by engulfing them with mucus and swallowing them whole!

Blood Fluke

Form and Function Feeding: Carnivores, parasitic Mouth with pharynx (muscular tube that moves food and waste)

Respiration, Circulation, Excretion Use diffusion for transport Some have flame cells to filter and remove waste Many flame cells form tubes that lead to pores on the skin

Response Ganglia for control (nerve cells). Eyespot – detect light. Some have specialized cell to detect chemicals,food,etc.

Movement Cillia Muscle cells

Reproduction Hermaphrodites Asexual by fission

Groups of Flatworms

Turbellarians Free-living Marine or fresh water

Flukes Parasitic Infect internal organs Blood flukes-works its way into your intestines Multiple host

Schistosomiasis-fluke eggs clot blood vessels, causing swelling of tissue. Caused by human waste in water supply.

Tapeworms Parasitic Lives in intestines Long and flat Scolex- suckers or hooks

Roundworms

Unsegmented Most are freeliving Digestive tract with two openings

Form and Function

Feeding Most are carnivores Use mouth parts and spines to catch food Some eat algae Some are decomposers

Respiration, Circulation, Excretion No internal transport- diffusion

Response Ganglia from head Simple structures to detect chemicals

Movement Hydrostatic skeleton Muscles and fluid in the pseudocoelom work together to produce movement

Reproduction Sexually Internal fertilization

Human Disease

Trichinosis Lives in intestines of mammals 1. Females burrow into intestinal wall 2. Eggs into larvae travel to organs by bloodstream.

Filarial Worms Live in blood vessels Transmitted by mosquitoes Can block the movement of fluids Elephantiasis

Ascaris 1. Eggs hatch in intestines 2. Burrow into bloodstream to lungs 3. Travel to air passages, then swallowed 4.Carried to the intestines

Annelids

Body segments True coelom lined with mesoderm

Form and Function Feeding and digestion Filter feeders to predators In earthworm pharynx to esophagus to crop to gizzard to intestine

Circulation- closed system, Two major blood vessels Dorsal runs to the head, Ventral to the tail Respiration- Through the skin, gills in aquatic annelids Excretion- Nephridia filters fluid in the coelom, anus for the digestive tract

Movement- Hydrostatic, setae Reproduction- Most are sexual, Hermaphrodites Clitellum used to form mucus ring

GROUPS OF ANNELIDS

Oligochaetes- Earthworms

Hirudinea- Leeches

Polychaetes Sandworms, bloodworms

Earthworm Dissection

External View

Internal Structure

Pharynx

Aortic Arches

Seminal Vesicle

Seminal Receptacle

Septum

Crop

Gizzard

Intestine

Ventral Nerve Cord

Dorsal Blood Vessel