Name: _____________________
Date: __________
Unit 7 Notes #3 - Phylum Platyhelminthes: Flatworms
A) Body Plan: - All have _________________________________
-_________________________________: Concentration of sensory organs and
nervous tissue at the anterior end of the body (__________).
-Well-developed _____________ ____________ layer called the _______________
between the ectoderm and endoderm.
-Mesoderm includes:
________________________________________________________________
-Possess an _____________________: single opening (mouth/anus) to the
gastrovascular cavity; use mouth to ingest food and use mouth to expel undigested
wastes.
B) Diversity:
1. Class __________________: -_______________________
-Incomplete gut
-No suckers or hooks
-Ciliated epidermis
Example: _________________
2.Class ________________: -______________________
-Incomplete gut
-______________________
-Outer Cuticle (tegument)
Example: _________________
PLANARIA
FLUKE
3. Class___________________: -______________
-______________
-_____________ and ____________together form a
_____________ for attachment to host
-Body consists of repeating sections called ________________________
Example : _______________________
C) ________________Common To Most________________ Flatworms:
1) Parasitic flatworms often have suckers and hooks for attachments, form a
structure called a _____________.
2) ______________________(_______________) for protection so as
________________________________or destroyed by the host.
3) Loss of digestive system in some (tapeworms) – these will ____________________
________________ nutrients through ectoderm.
4) Complicated life cycle with the production of many eggs and/or offspring and
________________________________________________________
D) Characteristics Of Common Platyhelminthes Members:
1. _________________
a. Digestion: Feed on small animals and the remains of larger dead animals.
-____________/_____________ is located mid-way along the ventral surface
(_______________________) it acts to push food into the gastrovascular cavity.
-________________________ are present in the pharynx and gastrovascular cavity
(they secrete enzymes to digest food)
-Gastrovascular cavity will also circulate nutrients and oxygen to various parts of
the body.
-Indigestible wastes are eliminated out of the mouth.
b. Nervous : -__________________________________________________________
-A pair of _______________________________________________run the length of a
nervous system.
-Connect to a pair of _________________________________(a group of nerve cells)
in the anterior end.
-Show cephalization with a variety of sensory cells.
-Sensory cells are sensitive to ____________________and various _______________.
c._______________: -_______________________________________ are located
below the ectoderm.
-The outer layer of ____________muscle that constrict the worm, making it
____________and _____________.
-Next layer uses __________________ muscles to _____________the worm.
-There is also a third layer that runs ___________________ (___________________)
and makes the worm a little flatter.
d. Locomotion: -Body moves by co-ordinating its muscles and __________________
______________________trail that it secretes from glands in the epidermis.
-_________ on the ventral epidermis assists in gliding.
2. _____________
a. Digestion: -They are___________________.
-Mouth present in the middle of the
_________________________________
-The pharynx swallows the host’s tissues and bodily fluids (blood) into its
____________________________
b. Circulation and Respiration
-Gastrovascular cavity for circulation and respiration.
-They live in tissues that are well supplied with nutrients and oxygen by the host’s
blood.
c. ________________: - ____________________________but they lack most of the
special sensory cells found in Planaria.
d. ____________: -Similar to planaria, _________________on the ventral
epidermis
3. ___________________
a. Digestion: -Have___________________________________________________.
-Attach themselves to the lining of the host’s intestine by _______________________
_____________________
Tapeworm’s Scolex
-Worm feeds by absorbing digested food.
-Have a modified epidermis called a _______________, this thicker skin prevents
them from being digested.
b) Circulation: -Receive oxygen from blood vessels in the host’s intestine.
-When oxygen is not available, ____________________________________________
E) Reproduction In These Three Common Members of Platyhelminthes:
1. Planaria: -Reproduce ______________________________________________
-Missing parts will ______________________
-Can also reproduce ______________
-______________________ (contains both sexes in one individual), but requires
reciprocal exchange of sperm and eggs between two individuals.
2._______________: -Also hermaphrodites
-Complex life cycle with numerous larval stages that_________________________
_________________
3. ________________: - Constantly ______________new body sections
(_______________) posterior to its scolex.
-Each proglottid contains both male and female reproductive organs.
-Mature proglottids with __________________________________________________
_____________________________
-Often have larval stages that infect a number of different hosts
Advances of the Platyhelminthes Over the Cnidaria
1. Platyhelminthes have their ______________________________________________
and even had some simple systems.
2) Unlike the previous two Phyla (Porifera and Cnidaria), the ___________________
_______________________________with the development of the middle layer (the
mesoderm). The mesoderm has also provided for better muscle development and
thus has resulted in an animal that moves around more efficiently.
3) As a result of moving around, platyhelminthes have further __________________
__________________________
4) Cnidarians had a nerve net for conducting impulses, but the Platyhelminthes
have ___________________________________________into two longitudinal nerve
cords. (____________________________________________________).
LIVER FLUKE lifecycle