ZOO 137 - Invertebrate Zoology Phylum Info File - Nematoda

Kingdom Animalia -- Subkingdom Metazoa
Phylum Nematoda (etymology: ____________________________________________)
(We will not deal with the classes of Nematoda.)

Things You Should Do Before Coming to the Lab on Nematodes

o Study Chapter 13 in Animals Without Backbones
o Complete plates 26 and 28-30 in The Zoology Coloring Book (optional but highly recommended)

Things You Should Do During the Lab

o Examine each of the following prepared slides at your desk:

Ascaris (x.s.) - This slide has a section through both male and female. Be able to
distinguish all the tissues and structures in PAZ Figs. 6.7 (a) and (b). Note
that in (b) guideline 10 indicates the ovary, not the oviduct
Trichinella spiralis- w.m. of a larval cyst in the muscle of its host. See PAZ Fig. 6.8 for
details. Each cyst contains a single, coiled worm. When the cyst was
sectioned to make the slide, the knife cut through the coiled worm in
several places giving the false appearance that the cyst contains
several worms.

o Study the model of Ascaris. This model depicts both sexes. Be aware of sexual differences. What are they?

o Examine the following demonstration specimens and slides:

Preserved specimens of dissected Ascaris - note the difference between sexes and
information in PAZ Fig. 6.2.
Preserved specimens of plants infected by root knot nematodes. Many roundworms are
serious pests of plants. (You can't see the worms; they're inside the "knots.")
A preserved meat sample containing cysts of Trichinella.
Slides illustrating some parasitic nematodes:
- Trichinella spiralis - w.m. of the adults (note the companion slide of its larva
mentioned above)
- Necator americanus -- w.m. of the adults and larvae
- Wuchereria bancrofti -- w.m. of infective larvae (microfilariae) in a blood sample

o Take careful notes on the life cycles of the following human parasites, which I will discuss during the lab period:

Ascaris lumbricoides -- human intestinal roundworm
Wuchereria bancrofti -- a microfilarial worm causing Bancroft's microfilariasis,
a.k.a. "elephantiasis"
Enterobius vermicularis -- pinworm
Necator americanus -- the American hookworm
Trichinella spiralis - the trichina worm

Things You Should Do After the Lab

o Using all sources available to you, make a list of ten important features, characteristics, etc. of the nematodes. Don't forget the pseudocoelom, their unusual body wall structure (involving the cuticle, epidermis and muscles) and tube-within-a-tube architecture.