Flatworms
1. Give the correct phylum name for each type of
unsegmented worm.
a) Flatworms: PLATYHELMINTHES
b) Roundworms : NEMATODA -Aschelminthes
2. What type of symmetry do all flatworms have?
BILATERAL
3. Most flatworms exhibit cephalization, but what
does this mean?
The gathering of sensory organs and central
nervous structures up to the anterior (front) end
of the body.
4. What is the difference between a “parasitic”
worm and a “free living” worm?
A “Free Living” organism does not depend on a
Host. Parasites need to feed off of a living host,
harming the host in the process.
5. How do flatworms get oxygen for their cells and
excrete metabolic wastes like ammonia and
carbon dioxide?
They rely on diffusion of goods and wastes with
the fluids (water,blood, food in gut) they are
surrounded by.
6. What are ocelli, and what function do they
serve?
They are light sensitive eye spots that can detect
light.
7. Many flatworms are hermaphroditic, describe
what this means.
They have both male and female reproductive
structures in the same individual.
8. Do most hermaphroditic worms use selffertilization? Most don’t.
9. Name the most common members of Class
Turbellaria:
PLANARIA
10. Name the most common members of Class
Trematoda:
FLUKES – blood, liver, intestinal
11. What takes place inside the “Primary” host of
a parasitic worm?
The parasite reaches adulthood and is now
capable of sexual reproduction.
12. If blood flukes live in the blood of their hosts,
how do the fertilized eggs of a blood fluke leave
their primary host?
The worms break open small blood vessels lining
the intestinal tract and spill out the eggs. These
eggs then leave with the gut with the feces.
13. The fertilized eggs of a blood fluke hatch to
form what?
Very small swimming larvae.
14. Give an example of an intermediate host of a
blood fluke?
SNAIL, CLAM, SLUG
15. Describe how a blood fluke would get from its
intermediate host into the blood stream of its
primary host?
Larvae reproduce asexually so that many burst
out of the intermediate host then the secondary
larvae enter the primary host via skin or food.
16. List the range of symptoms that a person
infected with a blood fluke may suffer.
General sickness, becoming very weak and
anemic. Often leads to premature death over
time.
17. What causes swimmer’s itch, and why don’t
those people with “swimmer’s itch” suffer the
same extreme of symptoms of those people
mentioned above?
Some blood flukes in North America use water
fowel (geese, ducks) as their primary host. The
larvae try to burrow into human skin. However,
they are not adapted to live in humans.
18. What are the most common members of Class
Cestoda?
TAPEWORMS
19. Describe a Scolex and what is its purpose?
A scolex is a collection of hooks and suckers used
to attach to the host’s gut wall.
20. How do tapeworms obtain their nutrients?
They absorb pre-digested nutrients directly
through their ectoderm - TEGUMENT
21. What name is given to the divided regions of a
tapeworm that burst open to release fertilized
eggs? PROGLOTTIDS
22. What organs are found inside a proglottid?
Both male and female reproductive structures are
in each segment.
23. What forms when a tapeworm larva
burrows into the muscle of an intermediate host?
A painful “CYST”
24. Describe how humans can get tapeworms?
When an organism (human) eats incompletely
cooked encysted meat products.