Answers Ws 26-4
Unsegmented Worms
p. 570-574
1.
Two phyla of unsegmented worms are. Platyhelminthes and Nematoda
2.
Define unsegmented.
Bodyies not divided into segmements
3.
Which phyla do flatworms belong to?
Platyhelminthes
4.
What does Platyhelminthes mean? Flat worm
5.
Define cephalization.
Development of an anterior end (head)
6.
Give the possible size of these worms.
Max few mm thick, up to 20m long
7.
How are flatworms more developed then the phyla porifera and cnidaria? More developed organ systems
8.
What do they eat? Free living forms are: Carnivores, scavengers (dead organisms)
9.
Where can they live?
Streams, lakes, oceans
10.
What is a pharynx? Tube which sucks up food
11.
Function? Puts food into gastrovascular cavity
12.
What does the gastrovascular cavity attach to?
intestine
13.
What happens inside the intestine? Enzymes break down the food into usable molecules
14.
How do the cells get their nutrients? Diffusion of nutrients out of the intestine
15.
Where does the waste go? Out the mouth
16.
What can the parasitic flatworms eat?
Blood, tissue fluids, or pieces of cells inside the body of their host
17.
What is a common flatworm parasite?
tapeworms
18.
How do tapeworms live?
Live within the intestines of their host. They absorb the food that has already been broken down by
their host
19.
Why do flatworms lack a circulatory or respiratory system?
They are so flat that diffusion can do the job to transport thing to
and away
20.
What is the function of the flame cells?
Help get rid of extra water (primitive kidneys)
21.
Which system is much more developed compared to the phyla porifera and cnidaria?
Nervous systems
22.
Describe the nervous system of a free-living flatworm.
Simple brain with long nerve cords running down the body,
shorter nerve cords run across the body
23.
What type of flatworm is shown on p 571? Planaria
24.
Describe 2 different sensory cells in a planaria
ocelli (light detection), chemoreceptors (chemical detection for food and
water flow)
25.
Explain fg 26-26. the planaria injured its head. It regenerated an extra head and will eventually form 2 complete new orgnaims
26.
Why do parasitic flatworms not have a well developed nervous system? They do not need to really do anything except eat and
reproduce while staying put in the intestine of their host
27.
Describe how free-living flatworms move.
Cilia & muscle cells to twist and turn for rapid reactions
28.
Fg 26-27. What is the class represented?
Turbellaria
(marine types vs fresh water types)
29.
Define hermaphrodite.
Have both male and female reproductive organs
30.
Briefly explain sexual reproduction in free-living flatworms.
Each worm delivers sperm to the other worm and fertilizes their
own eggs with the other’s sperm
31.
Describe 2 methods of asexual reproduction. Fission (spitting apart) & regeneration (the worm breaks into small pieces and each
piece develops into a new worm)
32.
How is parasitic flatworm reproduction different then free-living forms? There is no asexual reproduction, only sexual
33.
What class does the planaria belong to?
Turbellaria
34.
“General question” What is the “life style” of the class Turbellaria?
Most are free living, a few are parasitic
35.
What is the largest size?
60 cm
36.
What class does a Fluke belong to?
Trematoda
37.
What is their “life style”? parasitic
38.
The 2 “types” of flukes are?
Internal or external parasites
39.
Where do the external parasitic flukes live? Skin, mouth, gills, other outside parts of the host
40.
Where do the internal parasitic flukes live?
Blood and organs
41.
Define multiple host.
2 or more host animals involved during the reproduction of the fluke
42.
Where do blood flukes primarily live?
Blood, especially inside the vessels of the intestine
43.
What is a common genus? Schistosoma
44.
Define primary host.
Place were the adult is found here and sexual reproduction occurs here
45.
How many eggs can flukes produce?
Up to 100 000 times more then free living flatworms
46.
Where do the eggs end up going?
Burst the intestinal blood vessels and flow out the intestine with the host’s feces
47.
Why do developed countries not have as much of a problem with parasitic flukes as compared to underdeveloped countries?
Sewage sanitation kills most of the eggs at sewage treatment plants which undeveloped countries do not have: the sewage is used
as fertilizer or dumped into rivers and streams
48.
What do they hatch into?
Eggs hatch into swimming larva which burrow into snails
49.
What the function of the intermediate host for the fluke?
Provides a place where the larva can “hide out” and reproduce
asexually producing new worms that break out and swim around in the water
50.
How do the resulting worms get back inside the human?
Attach to Primary host skin, eat their way into blood vessels
51.
Where do they live as adults?
intestine
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52.
53.
54.
55.
What 2 methods, both directly or indirectly, can cause a human to die as a result of fluke infection? Fluke effect the proper
functioning of the organs or other diseases overwhelm the body due to the weakened condition of the fluke infected host
Why do we not worry about blood flukes in Vancouver?
It is too cold, most live in the tropics
What is “swimmers itch”? blood flukes are trying to burrow into your skin
Why is this a not a problem?
Our skin and insides are the wrong type; blood fluke dies
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