1. Clade Ecdysozoa-Molting Animals Ecdysis- “an escape” -molting of exoskeleton or cuticle Phyla- Nematoda and Arthropoda

2. Phylum Nematoda Nematodes: roundworms Nemata- “ thread”
Bilateral symmetry
Tube within a tube structure-mouth and anus
3 germ layers w/ pseudocoelom
Smaller than flatworms, taper at both ends

3. Pseudocoelomate Ectoderm Mesoderm Endoderm
Fluid filled cavity between the endoderm and ectoderm- pseudocoelom
Differs from a true coelom because….
It is not entirely lined with mesoderm tissue
Organs are not suspended or attached to membranes (mesenteries)

4. Lifestyle
Thick outer covering (cuticle) to protect them from harsh environment ex. Stomach acid
Move bodies with thrashing motion
Free living-Decomposers and predators (tremendously abundant)
Parasitic- ex. Ascaris, hookworm, heartworm-host is dog
Sexually reproduce:
most are separate sexes
some species are hermaphrodites

5. Nematodes Found everywhere
Soil
Oceans
Polar ice
Hot springs
Parasites of nearly all plant and animal species!

6. Body Systems
No Respiratory or Circulatory Systems- limits size of worm due to distribution of nutrients via osmosis and diffusion
Complete Digestive
Nervous
Muscular
Excretory
Reproductive

7. Digestive System Complete Digestive Tract- Mouth Pharynx Intestine
anus

8. Muscular System
Longitudinal muscles only
creates thrashing movement

9. Nervous System
Nerve ring – “brain”
Dorsal and
ventral nerve cords

10. Excretory System
Excretory cells
Ducts
pores

11. Nematode Reproductive Systems
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Nematode Reproductive Systems

12. Dioecious- separate sexes

14. Which is female?

15. Life cycles of parasitic roundworms
ASCARIS
lives in intestines and feeds off blood
ingest eggs from dirty hands or unwashed veggies contaminated with fecal matter
eggs hatch in intestines and enter bloodstream
larval worms bore into lungs, must be coughed up and swallowed
move to intestines where they mature
Animal planet.com-Baylisascaris, brain eating parasite

16. TRICHINELLA
bore into muscles causing painful cysts or live in intestines
ingest cysts in undercooked/raw meat (usually pork)
cysts open up in intestines and reproduce there
Animal planet- “worms borrow through flesh”

17. HOOKWORMS
lives in intestines
feeds on blood, causes major damage to intestines
eggs deposited on soil from contaminated wastes
larvae live in soil
burrow into feet or exposed skin of host
larvae travel through bloodstream, to lungs, coughed up, swallowed
attach to intestinal wall where they mature
Ap.com- “flesh eating hookworm”“worms crawling under my skin”

18. PINWORMS most commonly infects children lives in intestines
ingest eggs from contaminated soil or sand
hatch in intestines
female lays eggs near anus at night causing severe itching

19. Wuchereria bancrofti Lives in lymphatic system Vector- mosquito
Daytime-worms in lungs
Night-move to skin
Obstruct lymph to cause swelling
Mild- Filariasis
Severe- Elephantiasis

20. Elephantiasis Ap.com- “Parasite causes elephantiasis”
“40 year parasite”

21. Life Cycle of Wucheria spp.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Life Cycle of Wucheria spp.
Fig
11-13
Source: Redrawn From Centers for Disease Control, Atlanta, GA.

22. Loa loa Eye worm River blindness 2nd leading cause of blindness
Vector- deer fly or black fly
Ap.com- “river blindness”, “worms in my eye”

24. Dracunculus medinesis
Fiery serpent
Water contaminated with copepods carrying larva
Females migrate towards legs
Juveniles form blisters and exit via skin

26. Dirofilaria immitis
Dog heart worm

29. The End