1. Phylum: Nematoda pseudocoelomate “Radiata” Deuterostomia Protostomia
Porifera
Cnidaria
Chordata
Mollusca
Ctenophora
Phoronida
Annelida
Ectoprocta
Arthropoda
Rotifera
Nematoda
Brachiopoda
Nemertea
Echinodermata
Platyhelminthes
“Radiata”
Deuterostomia
Protostomia
Bilateria
Phylum: Nematoda
pseudocoelomate
Eumetazoa
Metazoa
Ancestral colonial
flagellate

2. Phylum: Nematoda (formerly Aschelminthes)
Kingdom: Animalia
Phylum: Nematoda (formerly Aschelminthes)
non-segmented, smooth worms
tapered at both ends
bilateral symmetry
>80,000 species described
most common soil inhabitant
15,000 parasitic species
generally less than 5 cm (some parasitic ones longer)
covered in thick, tough, protective cuticle
cuticle is a syncitial epidermis
molt several times during lifespan
triploblastic
pseudocoelomate- 1st group to evolve a body cavity

3. Phylum: Nematoda (formerly Aschelminthes)
Kingdom: Animalia
Phylum: Nematoda (formerly Aschelminthes)
pseudocoelomate- coelom partially lined with mesoderm

4. Advantages of Evolution of a Body Cavity
fluids moving within cavity can function as circulatory system
fluid in cavity makes body rigid allowing for muscle driven body movement, a “hydrostatic skeleton”
organs can function without being deformed by body movement
food movement not controlled by locomotion of animal making digestion and waste removal more efficient

5. Phylum: Nematoda (formerly Aschelminthes)
Kingdom: Animalia
Phylum: Nematoda (formerly Aschelminthes)
complete digestive system
one-way digestion (mouth and anus)
tube within a tube
nervous system
sensory structures and ganglia at head
nerve ring with ganglia around the pharynx
ventral and dorsal nerve cords
reproduction is sexual
most have separate males and females (dioecious)
reproductive organs in body cavity
females release chemical attractants

6. Phylum: Nematoda (formerly Aschelminthes)
Kingdom: Animalia
Phylum: Nematoda (formerly Aschelminthes)
locomotion
longitudinal muscles under epidermis
no circular muscles
can only undulate side-to-side (whip-like motion)
no cilia
“hydrostatic skeleton” aids in movement
excretory system
waste moved via fluid in body cavity
may have excretory ducts/pores as well as gland cells for waste removal
no respiratory or circulatory system
gas exchange by diffusion
food and nutrients distributed via fluid in body cavity

7. Phylum: Nematoda (formerly Aschelminthes)
Kingdom: Animalia
Phylum: Nematoda (formerly Aschelminthes)
cross-section

8. Phylum: Nematoda, Genus: Ascaris
Ascaris lumbricoides
parasite of humans that causes ascariasis
largest intestinal roundworm (15-35 cm)
can block intestine, bile duct, pancreatic duct
in tropical, sub-tropical areas with poor sanitation
caused by accidental ingestion of fertilized eggs
most common human helminth infection worldwide
infection easily treated with anti-helminthic drugs.

9. hookworms attached to intestinal mucosa
Phylum: Nematoda
Hookworms
hookworms attached to intestinal mucosa
adults attach themselves to intestinal mucosa
feed off of blood
can cause severe anemia
humans contract when larval form bores through skin after contact with contaminated soil
treatment: freezing if still on skin, anti-helminthic drugs

10. Phylum: Nematoda Pinworms Beware the 10 second rule!
geographically found everywhere, common here
common in school age children, spread by oral-fecal route
adult male 1-3 mm, female 8-13 mm
live in large intestine
eggs ingested hatch in small intestine, then migrate to large intestine to mature
eggs can survive 2-3 weeks outside human body
treatment: anti-helminthic drugs kill larvae and adult, not eggs
Beware the 10 second rule!

11. Phylum: Nematoda
Trichinella spiralis causes trichinosis
larvae encysted in striated muscle
cysts formed by host immune response
larvae passed to another organism when undercooked meat is eaten
in new host, cyst digested in stomach releasing worm, then adult develops in intestine
adult worms deposit larvae in lymph vessels and wall of intestine
larvae migrate throughout body
larvae that make it to muscle encyst in their new host

12. Phylum: Nematoda
Trichinella spiralis causes trichinosis
humans can get from eating undercooked pork
most damage of infection is when 1/2 billion larvae bore through the body at once
severe cramping, fever, anemia, weakness
some victims may have permanent muscular damage; others may die
prevention: thoroughly cook pork, freeze pork
rare in developed countries

13. Phylum: Nematoda
Trichinella spiralis
causes trichinosis

14. Phylum: Nematoda
Filaria worms
significant in human disease
intermediate host (vector) is arthropod
definitive host is a vertebrate
cause of...
elephantiasis in humans
heartworm in dogs

15. Phylum: Nematoda
Filaria worms:
Wuchereria bancrofti causes the disease elephantiasis
found in tropical and subtropical areas
spread by bite of certain mosquitoes
adult worms live in lymphatic system
accumulate to large numbers and block lymph flow
causes fluid accumulation, swelling, especially in the lower extremities

16. filaria worms cause the disease elephantiasis

17. Just FYI:

18. Phylum: Nematoda
Filaria worm causes heartworm in dogs
intermediate host = mosquito
definitive host = dog
fatal to dog

19. Phylum: Rotifera pseudocoelomate “Radiata” Deuterostomia Protostomia
Porifera
Cnidaria
Chordata
Mollusca
Ctenophora
Phoronida
Annelida
Ectoprocta
Arthropoda
Rotifera
Nematoda
Brachiopoda
Nemertea
Echinodermata
Platyhelminthes
“Radiata”
Deuterostomia
Protostomia
Bilateria
Phylum: Rotifera
pseudocoelomate
Eumetazoa
Metazoa
Ancestral colonial
flagellate

20. Kingdom: Animalia Phylum: Rotifera microscopic (50µm - 2mm long)
usually free-living, in moist soil or aquatic environments
corona
double crown of cilia at anterior end
look like rotating wheels when they beat
draw water current into mouth for feeding & locomotion
foot
at posterior end
when feeding, attaches to surface
nearby cement gland generates the adhesive
mastax
complicated muscular pharynx
seven hard jaw-like structures crush food

21. Kingdom: Animalia Phylum: Rotifera pseudocoelemate
complete digestive system
have excretory and reproductive systems
no circulatory or respiratory system
reproduction can be sexual or by parthenogenesis
parthenogenesis- in some species females produce 2 different kinds of diploid eggs, female and male, that develop without fertilization to diploid adults
in some species, eggs can develop as dwarf males that cannot even feed themselves, only survive long enough to produce sperm to fertilize females (sexual dimorphism- sexes take on 2 different forms)

22. cilia beat in opposite directions to create current
Kingdom: Animalia
Phylum: Rotifera
cilia beat in opposite directions to create current
(cement glands)

23. The Table for Nematoda:
Symmetry: bilateral
Segmentation: none
Mesoderm present: yes, triploblastic, has only longitudinal muscles
Type of body cavity: pseudocoelomate; fluid filled pseudocoel enclosed by cuticle forms hydrostatic skeleton
Ciliated larva: have larva that molt (shed cuticle as they grow)
Protostome: no? (this is under debate among scientists, newer molecular evidence may revise this)
Cleavage/cells: determinate
Nervous system: present; 2 nerve cords (dorsal & ventral)

24. The Table for Nematoda:
Digestive system: complete one-way system (mouth & anus); pharynx usually muscular; some heterotrophs but mostly parasites
Excretory system: yes, excretory ducts and pores to eliminate waste, some have gland cells and/or canal systems, too
Reproductive system: sexes usually separate (dioecious); male reproductive tract opens to rectum forming common exit called the cloaca; female reproductive tract opening separate from digestive tract
Circulatory system: none
Members: hookworms, pinworms, common roundworm, trichinella
Habitat: moist soil; the most numerous inhabitant of the soil; also found in aquatic environment; some parasites
Relationship to other phyla: N/A

25. The Table for Rotifera:
(If nothing is listed for a category, assume it is the same as for Nematoda.)
Reproductive system: sexual or by some by parthenogenesis (produce diploid eggs that grow to diploid adult without fertilization); some exhibit sexual dimorphism producing degenerate dwarf males that live only long enough to fertilize eggs
Members: rotifers
Habitat: freshwater and marine environments, moist soil
Relationship to other phyla: cuticle suggests rotifers are close relatives of roundworms