Name___________________________________ Period ___________ Date _____________________
Platyhelminthes Lab
(and review)
In parts 1-4 you will compare cross-sections of four different Phyla: Porifera, Cnidaria, Platyhelminthes,
and Nematoda (we haven’t studied the last one yet). You should be able to observe, identify, and
appreciate the differences between:
 Monoblastic vs Diploblastic vs Triploblastic
 Acoelomate vs Pseudocoelomate
In parts 5-7 you will observe whole mounts of three of the major Classes of Platyhelminthes: Trematoda,
Cestoidea, and Turbellaria. You should be able to observe, identify, and appreciate the importance of the
closed intestine, pharynx, and major reproductive organs.
PART 1: Porifera cross section
1.
Draw the sponge.
2.
Label the: spongocoel, radial canal, ostia, choanocytes,
mesoglea.
3.
Which type of canal system does this sponge exhibit?
4.
Is this animal Mono-, Diplo-, or Triplo-blastic?
5.
How/where does this animal digest food?
PART 2: Cnidaria cross-section
1.
Draw the anemone.
2.
Label the: epidermis, gastrodermis, gastrovascular cavity, mesoglea.
3.
What body form does this specimen exhibit: polyp or
medusa? What is the difference?
4.
Is this animal Mono-, Diplo-, or Triplo-blastic?
5.
How/where does this animal digest food?
1
PART 3: Platyhelminthes cross-section
1.
There are THREE cross-sections of this specimen on the slide, taken progressively further from the head
to tail region. You will need to observe all three to fully appreciate the animal’s structure.
2.
Draw the planarian.
3.
Label the: epidermis, intestine, pharynx, muscles.
4.
Is this animal Mono-, Diplo-, or Triplo-blastic?
5.
6.
How/where does this animal digest food?
Is this animal an Acoelomate or Pseudocoelomate?
What is the difference?
PART 4: Nematoda cross-section
1.
This is an Ascaris worm, from the Phylum Nematoda. We haven’t studied them yet, but you can still
notice some important structures.
2.
There are TWO cross-sections on this slide: one
from a male and the other from a female worm.
3.
Draw the Nematode.
4.
Is this animal Mono-, Diplo-, or Triplo-blastic?
5.
Is this animal an Acoelomate or
Pseudocoelomate?
2
PART 5: Taenia – tapeworm whole specimen
1.
Tapeworms are composed of hundreds of repeating
compartments called proglottids. This slide has two
proglottids separated from the whole worm.
2.
Draw a proglottid.
3.
To which Class does this specimen belong?
4.
What does “gravid” mean?
5.
Where does this Class usually live?
PART 6: Planaria whole specimen
6.
Draw the planarian.
7.
Label the: pharynx, intestine, eye spots.
8.
To which Class does this specimen belong?
9.
Where does this Class usually live?
PART 7: Fasciola – whole specimen
1.
Draw the worm.
2. Label the: ventral sucker, oral sucker.
3.
What is the purpose of the two suckers?
4.
To which Class does this specimen belong?
5.
Where does this Class usually live?
3
1. How is reproduction in Porifera, Cnidaria, and Platyhelminthes similar?
2. How many cell layers are Porifera, Cnidaria, and Platyhelminthes as embryos? Why does this matter?
3. What major advancements do Platyhelminthes show compared to Cnidaria?
a.
b.
c.
d.
4. What major similarity do Cnidarians show compared to Platyhelminthes in terms of digestion? What major
difference is there?
4