Unit 8
Phylum Platyhelminthes
Phylum Platyhelminthes
(8 days)
Enduring Understanding:
 The student will be able to understand that members of Phylum Platyhelminthes are phylogenetically important transitional animals
between radial animals and more complex bilateral animals. The four major classes of flatworms classified under Phylum
Platyhelminthes are Class Turbellaria, Class Monogenea, Class Trematoda, and Class Cestoidea.
Essential Questions
 What are the various representative
organisms found in Phylum

Platyhelminthes? (1 day)
 What are the general characteristics of
flatworms? (2 days)
 What does triploblastic germ layer
mean in relation to flatworms? (2 days)
 What types of flatworms cause disease 
in humans? What are their methods of
reproduction and lifecycles? (2 days)
 How do flatworms fit into the

evolution of organisms in the animal
kingdom? What types of characteristics
did they develop and where do they fit

in phylogenetically? (1 day)
SC.912.L.15.1 Explain how the scientific
theory of evolution is supported by the
fossil record, comparative anatomy,
comparative embryology, biogeography,
molecular biology, and observed
evolutionary change.
SC.912.L.15.3 Describe how biological
diversity is increased by the origin of new
species and how it is decreased by the
natural process of extinction.
SC.912.L.15.4 Describe how and why
organisms are hierarchically classified and
based on evolutionary relationships.
SC.912.L.15.6 Discuss distinguishing
characteristics of the domains and
kingdoms of living organisms.
 SC.912.L.15.7 Discuss distinguishing
characteristics of vertebrate and
representative invertebrate phyla, and
chordate classes using typical examples.
 The student will understand the
biological contributions from Phylum
Platyhelminthes.
 The student will be able to compare
and contrast the anatomy and
physiology of Phylum Platyhelminthes
with previously studied phyla.
 The student will be able to identify
representative organisms found in
the four major classes of flatworms:
Class Turbellaria, Class Trematoda,
Class Monogenea, and Class
Cestoidea.
 The student will be able to summarize
the life cycles of some representative
animals in Phylum Platyhelminthes,
such as C. sinensis (Chinese liver
fluke), Schistosome sp. (blood fluke),
Taenia sp. (pork tapeworm), and
Taeniarhynchus saginatus (beef
tapeworm).
 The student will be able to explain
the various parasitic relationships
between members of Phylum
Platyhelminthes and humans, such as
Schistomiasis, Swimmer’s Itch, and
Cysticercosis.