Roundworms Phylum Nematoda

Nematodes Tube within a tube body plan psuedocoelom = hollow, fluid filled cavity most are free living, some are parasitic

Stomach Worm Ascaris lumbricoides Trichinosis - from consuming raw meat, causes muscle pain & stiffness.

Filarial Worms Elephantiasis Heartworm in dogs & cats These worms live in and affect the lymphatic system, fluid builds up

Hook Worms Feed on the hosts blood Can cause anemia

Pin Worm Affect the lower part of the intestine Prevalent in small children Lay eggs around the anus; causing kids to scratch and then spread the eggs

Classification Common Name: Stomach Worm Scientific Name: Ascaris lumbricoides Phylum: Nematoda Class: Ascarid Other Classification: Roundworms

Characteristics Body Plan: Unsegmented, round Body Cavity: Psuedocoelom “false cavity” Symmetry: Bilateral Cell Specialization: Organs = mostly reproductive; parasitic lifestyle with human as host

Life Support Processes Absorption: Digestive tract Feeding: parasitic Digestion: mouth --> digestive tract --> anus Respiration & Circulation: Diffusion through the body wall, moist skin Excretion: Body wall, anus

Male vs Female Male = shorter than female and the end is hooked

Life Support Processes Secretion: digestive enzymes, cuticle Response: Ganglia = groups of nerve cells, skin Movement: longitudinal muscles, thrashing motion Reproduction: Sexual, separate males and females Support: Hydrostatic skeleton

Ecological Relationships Parasite with humans as host Complex life cycle Spread through contaminated food, water, and through the skin

Body Systems Compared With Humans Intestines Reproductive Organs

Advancements Over Previous Phylum 2 Opening digestive tract Muscles

Ascaris Diagram

Nasty Nematodes! Nematode sea worms are the most abundant animal on the planet with a population estimated to be over: 400,000,000,000,000,000,000,000! One ascarid female can produce over 200,000 eggs in a single day! The largest roundworm, Placentonema gigantisma, is a parasite found in the placenta of sperm whales which can reach up to 9 m in length!