NAME:
UNSEGMENTED WORMS
DATE:
PHYLUM PLATYHELMINTHES
PHYLUM NEMATODA
BLOCK:
Why do we call Platyhelminthes and Nematoda UNSEGMENTED WORMS?
PHYLUM PLATYHELMINTHES (FLATWORMS)
-
‘Platy’ means _______________ and ‘helminthes’ refers to
___________________.
-
Flatworms are flattened ________________________ and are usually
no more than a few millimeters thick. But flatworms can get extremely
long – the record is set by a tapeworm found to be 39 meters long!!!
-
Flatworms have _________________ symmetry.
-
They also have an easily distinguishable __________________ and ________________ end.
-
Flatworms are found in ______________________ environments.
-
There are 3 Classes of flatworms:
o Class _____________________ - planarians and marine flatworms
o Class _____________________ - flukes
PARASITIC
o Class _____________________ - tapeworms
Mr. Lau
Page 1 of 7
Biology 11
FEEDING
Please label this planarian:
-
Free-living planarians have a gastrovascular cavity with just
_________ opening. At the end of this opening, there is a
muscular tube called a ____________________ where the
____________ is.
-
The gastrovascular cavity branches off and forms
____________________.
-
Planarians are either _________________________ or
scavengers.
-
Most flukes and tapeworms are parasitic so feeding is
much simpler. These parasites may feed on
_______________ or already digested food from the
____________________ of the host. These animals can
attach themselves to a host with ________________
and/or ________________. These structures are found
on the ______________ or head of a tapeworm.
Draw the scolex of a
Draw the scolex of a tapeworm:
tapeworm:
-
Because of the parasitic lifestyle the digestive tract that is
much ____________________.
Mr. Lau
Page 2 of 7
Biology 11
RESPIRATION, INTERNAL TRANSPORT, AND EXCRETION
Why can flatworms rely on diffusion for respiration and waste removal?
Planarians also have _____________________ that get rid of excess ____________________.
There cells are precursors to the kidneys found in vertebrates.
RESPONSE
-
We can easily identify the _____________ end of a planarian because of a process called
_____________________ where a head is formed. This head contains a rather simple
_______________. From this structure, a ladder-like network of _______________ run along
the body
-
How is the environment detected by a flatworm (planarian)?
-
Parasitic cestodes and trematodes do not have much need for a nervous system since their
lifestyle is very ___________________.
SUPPORT SYSTEM AND MOVEMENT
What 2 things do planarians use to move around?
Mr. Lau
Page 3 of 7
Biology 11
REPRODUCTION
-
Planarians are ________________________ and can produce both ___________________ and
____________________.
Outline SEXUAL reproduction in planarians:
Outline ASEXUAL reproduction in planarians:
How do people become infested with parasitic flatworms?
How do tapeworms reproduce? What structures are involved?
Mr. Lau
Page 4 of 7
Biology 11
PHYLUM NEMATODA (ROUNDWORMS)
-
Nematoda = thread-like
-
Roundworms are probably the most abundant of all multicellular animals – chances are, you make contact with a
roundworm everyday!
-
There are both free-living and ______________________
species of roundworms living in all types of environments.
-
For the first time, we see the anatomical features of a tube
within a tube body plan (a pseudocoelom).
FEEDING
What do roundworms eat?
How is the digestive tract of a roundworm different from that of a flatworm?
How are roundworms harmful to certain agricultural products?
Mr. Lau
Page 5 of 7
Biology 11
RESPIRATION, INTERNAL TRANSPORT, AND EXCRETION
Once again, respiration (oxygen), waste excretion (ammonia and
carbon dioxide), and internal transport (of nutrients) depend on
diffusion to move through body walls or within the body.
RESPONSE
-
Roundworms have several ____________________ which are groups or clusters of nerve cells.
Nerves extending from these clusters run the length of the body and transmit sensory
information and control of movement.
SUPPORT SYSTEM AND MOVEMENT
-
The fluid-filled pseudocoelom acts as a ____________________________ skeleton.
-
Roundworms have strips of muscle down the length of their body.
How does movement of a roundworm on land differ from movement of a roundworm in water?
REPRODUCTION
Roundworms generally have ______________________sexes and reproduce sexually. Thus, each sex
has a different set of reproductive organs. Fertilization takes place ______________ the body of the
female.
Mr. Lau
Page 6 of 7
Biology 11
Outline the stages of the life cycle of a common parasitic roundworm, the human ascarid (Ascaris
lumbricoides):
Stage
What happens?
Where does this happen? What
parts of the human body are
involved?
1
2
3
4
5
ROUNDWORMS AND US
Identify and describe some diseases caused by roundworms.
Mr. Lau
Page 7 of 7
Biology 11