Download Ch. 33 1. Which of the following regarding sponges is true? a

Ch. 33
1. Which of the following regarding sponges is true?
a. Sponges only live in marine environments
b. Choanocytes capture food particles then deliver them to other cells in the
sponge
c. Sponges are considered uniblastic
d. An individual sponge can produce both sperm and eggs
e. Amoebocytes help power the flagellum of the choanocytes
2. What exactly is the mesohyl of a sponge?
The mesohyl is he gelatinous “middle matter that separaes the outer layer
(epidermis) from the inner layer (consists of amoebocytes, choanocytes, and
spicules) in the body of a sponge.
3. How does exactly does a cnidocyte function?
Inside of the cnidocyte there is a specialized type of cnidae called a
nematocyst, which houses stinging thread. When a trigger is stimulated, the
thread shoots out and punctures then poisons its prey.
4. In the lifecycle of Obelia a planula settles and develops into a new polyp.
Eventually, budding results in many interconnected polyps. Is each individual
polyp considered a separate organism or is the whole colony of polyps one large
organism?
Each individual polyp is considered a separate organism. The budding is a
type of asexual reproduction that results in a large number of interconnected
polyps.
5. What is zooxanthellae?
Zooxanthellae is a type of algae that forms a symbiotic relationship with
certain types of cnidarians. In this relationship, the zooxanthellae provide
products of photosynthesis in exchange for certain nutrients from the
cnidarians.
6. True or False: Flatworms are acoelomates therefore they do not go through
triploblastic development.
False, animals that go through triploblastic development can still be
acoelomates. Flatworms do go through tripoblastic development.
7. How does a planarian reproduce?
Asexually through fission during which a parent separates head end from tail
end and each develops into a new planarian. Planarians are hermaphrodites
and can sexually reproduce through cross fertilizaiton.
8. A researcher observing the life cycle of a certain blood fluke. The researches
notices that this blood fluke has just reproduced sexually. What type of host is this
researcher observing?
Blood flukes reproduce sexually in human hosts.
9. How does a tapeworm obtain nutrients from its host?
The tapeworm uses the hooks and suckers on its scolex hold itself onto the
intestines of its host. It then just absorbs nutrients with its body surface.
10. Which type of lophotrochozoan does parthenogenesis. What exactly is
parthenogenesis?
Rotifers are the type of lophotrocozoan that does parthenogenesis.
Parthenogenesis refers to the type of asexual reproduction during which a
species of only females produce more females from unfertilized eggs. Under
certain conditions, a female will produce eggs that become males also so that
sexual reproduction can occur. This sexual reproduction leads to eggs that
will remain dormant for however long necessary and then those eggs will
develop into a new female generation.
11. Brachiopods look similar to clams. What is the difference?
The two halves of a brachiopod shell are arranged differently than the two
halves of a clam or other hinge-shelled mollusc.
12. Both Ectoprocta and Brachiopoda are lophophorates. What does this mean? Do
lophophorates have a coelom?
If they are lophophorates that means that they have a lophophore. A
lophophore is a crown of ciliated tentacles around the mouth of these
organisms that helps draw in food towards the mouth. Yes, lophophorates do
have a coelom.
13. What are the three main parts of the body of a mollusc? What does each part do?
Foot- helps with movement
Visceral mass- contains all major organs
Mantle- a fold of tissue that drapes over the visceral mass and can secrete a
shell in shelled molluscs.
14. True or False: A chiton has a segmented body?
False. The shell of the chiton is segmented, however, the body is not
segmented.
15. True or False: The formation of a shell in a gastropod is separate process from
torsion.
True. Torsion is the process during which the visceral mass rotates up to 180° resulting in the anus being near the head. The formation of the shell is a separate process.