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

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

3. 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

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

5. 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

6. 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

9. 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

11. 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

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

15. 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

17. 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