ZOO 137 - Invertebrate Zoology Phylum Info File -- Platyhelminthes

Kingdom Animalia
Subkingdom Metazoa (etymology: ______________________________________________)
Phylum Platyhelminthes (etymology: ________________________________________)

Class Turbellaria (etymology: ________________________________________)
(examples: ________________________________________________)

Class Trematoda (etymology: ________________________________________)
(examples: ________________________________________________)

Class Cestoda (etymology: __________________________________________)
(examples: ________________________________________________)

Things You Should Do Before Coming to the First Lab on Platyhelminthes

o Memorize the classification given above.
o Study Chapters 9 and 11 (but not 10)in Animals Without Backbones (note that there are many
drawings and photographs that will help you interpret the material you see in the lab)
o Complete exercises 20-25 in The Zoology Coloring Book (optional but highly recommended)

Things You Should Do During the Lab

We will devote two lab periods to the flatworms. During the first lab you should make as much progress as you can toward examining the materials specified below. During the second lab we will discuss the several parasitic flatworm life cycles you will need to know.

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

Planaria (w.m. and x.s.) - Compare with the model and PAZ Figs. 5.1, 5.2 and 5.3 . Be
able to distinguish the tissues, etc., labeled in these figures.
Bdelloura (w.m.) - This flatworm is a relative of Planaria. Can you identify its gut? eyespots? pharynx?
Clonorchis sinensis - a w.m. of a stained adult (compare with the model and PAZ Figs.
5.7 and 5.8. Be able to recognize all organs indicated in Fig. 5.8
except numbers 4, 10, 13, 15 and 16.
Fasciola hepatica - a w.m. of a stained adult. Note that unmounted adults are shown in
the life cycle demonstration on the front desk. Compare with PAZ Fig.
5.5 and be able to recognize the suckers, uterus, eggs and intestine.
Taenia pisiformis ("composite") - This slide contains three body sections: the scolex +
strobila, a section of immature proglottids, and a section
of mature proglottids. See PAZ Figs. 5.12 - 5.15. Be
able to recognize the structures in Figs. 5.12
and 5.14 (numbers 1-4 only).
T. pisiformis -- a w.m. of a cysticercus, the cyst stage that lies quiescent in the tissues of
its intermediate host. The living cyst was a spheroid, and when it was
mounted on the slide, it was mashed flat. Even so, you can very easily
make out the invaginated scolex inside the cyst.

o Examine the following five models with the idea of learning the organs and organ systems specified on the keys:

Clonorchis sinensis - the human (Asian) liver fluke
Planaria - a free-living flatworm
Dibothriocephalus latus - the fish tapeworm
Taenia pisiformis - a dog tapeworm (adult proglottids)
T. pisiformis - the scolex

o Examine the following demonstration specimens and slides:

Echinococcus granulosus -- - the adult (note how small it is; it consists of the scolex and
only three proglottids)

Schistosoma sp. (there are several species of schistosome blood flukes) - six slides depicting life history stages:

- the eggs (notice they have a spike; it perforates the vein to allow the parasite to
escape the body via feces or urine; the eggs cause to worst clinical
symptoms of schistosomiasis.)
- the miracidium larva
- the sporocyst
- the cercaria larva (notice its tail is forked)
- the adults (they mate for life; where does the female reside?)
- a liver section showing flukes (in x.s.) clogging the veins

Fasciola hepatica -- Loose specimens and five slides showing different life history stages:

- the adults (these are in a small jar to show you what they look like when they tumble
out of a sheep's liver! One of the prepared slides shows an adult stained
to show different organs.)
- the eggs
- the miracidium larva
- (the miracidium is followed by the sporocyst stage, of which there is no slide)
- rediae
- the cercaria larva (note its tail isn't forked)
- the metacercaria (this cyst occurs on vegetation; where does the metacercaria of
the human liver fluke hang out?)

(NOTE: There also will be several preserved tapeworms in jars.)

Things You Should Do After the Labs

o Using all sources available to you, make a list of ten important features, characteristics, etc. of the platyhelminths.

o Be sure to correlate what you've observed in lab with your readings and lecture notes.

o Review carefully the several life cycles you must know. These are Fasciola hepatica; Clonorchis sinensis; Schistosoma mansoni; Taenia solium; T. pisiformis, Taeniarhynchus saginatus; Dipylidium caninum, and Echinococcus granulosus. They will be tested heavily on all the examinations.