Kingdom Animalia: Phylum Nematoda: The Roundworms Biology 11 Kingdom Animalia: Phylum Nematoda: The Roundworms

Phylum Nematoda Objectives Advances over Platyhelminthes Body plan and body systems 2 broad types and their example animals Parasitic worms (enter, live, hosts, effects)

The Pseudocoelomates Characteristics and Advances 1. Evolution of the anus allows for a complete digestive system - tube within a tube body plan 2. A pseudocoelom between mesoderm and endoderm

Phylum Nematoda The Roundworms A very large phylum, found in almost all habitats most are small to microscopic Reproduction is mostly sexual Hookworms

Phylum Nematoda A. Free living nematodes Most nematodes live in water or soil They are important in the ecology of soil - decomposers A Soil Nematode

Phylum Nematoda B. Parasitic Nematodes Some of the worst worm parasites are members of this phylum 1. Ascaris sp. the Intestinal Roundworm Most common world wide worm parasite - over 1 billion people have it Lives in small intestine but travels through the body as a juvenile

Phylum Nematoda 2. Hookworm Human hookworm (Necator sp.) feeds on blood from inside of intestine A single worm can drain 20 ml of blood per day Most serious in children as can lead to physical and mental retardation Enters as “Itch worm” between toes

Phylum Nematoda 3. Pinworm (Enterobius sp.) Lives in lower bowel Female migrates out anus each night to lay eggs Secretes irritating toxin to get person to scratch Re-infection is oral

Phylum Nematoda 4. Trichinella From eating undercooked pork Invades selected muscles forming painful cysts Causes Trichanosis

Phylum Nematoda Causes Elephantiasis 5. Filarial Worm Small nematode that lives in human lymph ducts and blocks them As a result, fluids can’t drain so accumulate resulting in severe, grotesque swelling below where the worm is Causes Elephantiasis

Phylum Nematoda 6. The Guinea Stick Worm (Dracunculus sp.) In Africa only Enters while a person is in contaminated water and burrows through skin and grows No cure - is removed by wrapping around a stick - one turn per day Contains deadly toxin if broken it can kill its victim