ZOO Ch.14,16,18 Flatworms, roundworms, mollusks

Because shells require it, land snails are limited to soils that contain some level of

Calcium

The cephalopoda are a derived version of the standard molluscan body plan. click those characteristics below that add complexity for most of members of the class (do not click standard molluscan features).

Complex eyes, Closed circulatory system, Beaklike jaws, and skin pigment cells (for changing color)

How could you become infected with adult tapeworm?

Eating insufficently cooked pork

members of the class cephalopoda are very different from all other molluscs. They have a closed circulatory system, highly specialized photoreceptors, possess very large brains, display elaborate color patterns, and are very active animals. Which of the following statements are true and may help explain the uniqueness of the cephalopods?

Elaborate color pattern displays are the result of the evolution of the use of color change in courtship displays.

a completely new combination of characteristics is revealed in the group that contains the flatworms and their distinct relatives. This group is called the Lophotrochozoa. Click on the characteristics or terms below found in this group.

Flatworms, Bilateral symmetry, Triploblastic, If cut lengthwise down the middle, the two halves of the body would mirror each other, and lacks a mesoderm-lined body cavity.

A filarial worm which infects dogs, particularly common in the United States, is

Heartworm

If the main disease symptom is anemia (low red blood cell count), the most likely nematode parasite is

Hookworm

which of the following statements is NOT TRUE of cephalopods?

Most have color vision

which of the following statements is NOT correct about nematodes?

Nematodes are all carnivores but may be free-living or parasitic

The newest clam shell is built

On the inside so the inside nacreous layer is the newest

Platyhelminthes are

All choices are correct

Torsion

All of the choices are correct

gaseous exchange in gastropods may involve

All of the choices are correct.

the radula

All of the choices are correct.

Cultured pearls are made by

Placing an irritating particle under the shell mantle

Most cephalopods have an ink gland that secretes ______________, a dark fluid containing melanin, to confuse enemies.

Sepia

Based on recent molecular analyses, which of the animals listed below likely share ancestral predecessors with the Mollusca?

Tapeworms (flatworms)

where would you locate the coelomic cavity when dissecting a mollusk such as a clam?

The cavity around the heart, the kidneys, and the lumen of the gonads forms the limited coelom

which of the following statements about planaria is NOT true?

The rudimentary circulatory system has a small central heart

what is there about snails and other members of their class that makes them different from the other members of this phylum?

Their bodies twist 180 degrees bringing the posterior most part of the body just behind the head.

the parasite found in the U.S. where people contract it by eating poorly cooked pork, bear meat, etc is

Trichinella

while wading in the ocean, you find a shelled animal using its radula to graze algae off of rocks. As you approach and try and pick it up you find it tightly suction-cupped to the rocks. Additionally, you notice that it has a body protected by eight armored plates (valves). This would be enough evidence to come to the conclusion that you have found a member of the class Polyplacophora.

True

Clams burrow by using

a foot

the nervous system of a freshwater planarian consists of

a simple brain of ganglion cells leading to a ladder-type nerve network

Since flatworms and ribbon worms lack a coelom or a pseudocoel, they are termed _____________ animals.

acoelomate

Animals with three well-defined germ layers and that have one solid mass of tissue rather than tissues and organs nestled inside a body cavity are

acoelomate and triploblastic

The central axis around which the shell of a snail coils is called the

columella

A farmer in a rice paddy in Asia becomes infected with the liver fluke by

eating infected fish that is undercooked or uncooked.

Platyhelminthes have

flame cells

the name "hookworms" is due to the fact they

have an anterior end that curves dorsally like a hook

Elephantiasis is an enlargement of legs, arms, scrotum, and other tissues caused by

microscopic nematodes that reproduce and clog lymph glands, causing infection and limbs to swell

if an individual turbellarian contains organs of both sexes, it is termed ________ or hermaphorditic.

monoecious

Elephantiasis is transferred by

mosquitoes injecting larval worms into the bloodstream

Turbellarians have light-sensitive organs called ___________.

ocelli

Much of the success of nematodes is due to their

outer, noncellular, collagenous cuticle

the _______ is the layer in the outside of the clam is mussel shell that provides protection that acidic water and may be colored to hide the clam in the mud.

periostracum

Most common helminth parasite in the United States is

pinworm

the mild nematode infection somewhat common among children in the southern U.S., and transmitted as eggs from anal to oral regions by the hands is

pinworm

the main reproductive body "segment" of the cestode is called the _________

proglottid

The tongue-like, rasping organ in the head of many molluscs is the _____________.

radula

imagine a situation where you were living near a volcano and suddenly you saw the air fill up with ash from an eruption. Certain types of environmental disturbances have a similar, though less catastrophic and more long term, impact on bivalves. All of the events listed can negatively impact bivalves. Which one of the events, from a clam's point of view, represents a roughly equivalent event as the volcanic ash?

removal of riverbank vegetation so that silt and clay erosion from soil moves with rainwater into the river.

The holdfast of a tapeworm is its _______________.

scolex

The region used for attachment of a tapeworm is called the

scolex

The long chains of bags of eggs, which hang behind the head of a tapeworm, is called a

strobila

The cephalopod nervous system is best described as

the most advanced among molluscs

because they have three germ layers, flatworms and ribbon worms are __________.

triploblastic

the ___________ is the oldest part of the shell and growth occurs in the concentric rings around it.

umbo

which of the following is NOT a factor that protects North Americans from many parasitic worm infections?

we have superior drugs and surgeons.

Build-a-mollusca box

Ahead connected to foot, Cape like mantle, Dorsal mass with digestive organs, Gills, Mantle cavity, Heart located in Coelom, and rows of rasping teeth.