chapter 34 hw bio 112 sp 17

At a celebratory dinner for a recent publication, a marine biologist ordered the lobster claw appetizer. What part did she order?

Cheliped

Why doesn't a tapeworm have a mouth on its scolex?

Endoparasites don't need a mouth

The excretory structures of terrestrial arthropods are slender projections from the digestive tract that are attached at the junction of the midgut and hindgut. These are called

Malpighian tubules.

The passage of an arthropod through stages from egg to adult is

metamorphosis.

Annelids and arthropods were once considered closely related. Some juvenile forms of arthropods resemble annelids (maggots and caterpillars). However, modern classification schemes separate them into distant groups. What feature suggests a fundamental difference between the two groups?

Whether growth is continuous or step-wise

Interoctopus communication is facilitated by

chromatophores.

You and your biology lab class take a field trip to a marine aquarium. Your guide is a marine biologist who studies squids. She explains to your class how squids are able to blend into their environment. She points out that squids have pouches of pigments embedded in their epithelium. The pouches are called

chromatophores.

Trochophores, the free-swimming larvae of many mollusks, are propelled through the water by

cilia.

Nauplius, a unique kind of larva, is characteristic of

crustaceans.

Which one of the following incorrectly matches a molluscan structure with its typical function?

ctenidia—secretion of the shell (when present)

In the Bryozoa and the Brachiopoda, the lophophore is a ciliated, circular or U-shaped structure that is used for both _________________ and __________________

gas exchange; feeding

Parasitic leeches possess a number of adaptations associated with blood-feeding. Evaluate the following statements about blood-feeding in leeches and determine if they are true or false.

1. All leeches are ectoparasites that suck blood from their hosts. False 2. The muscular pharynx acts directly to pump the blood from the host into the leech. True 3. Leeches secrete anticoagulant to keep the blood of their host flowing. True 4. Leeches avoid being detected when biting their host by injecting an anesthetic into the host's wound. True 5. Blood-feeding leeches often detect hosts by sensing gradients of nitrogen gas (N2) in the environment. False

In a tidepool, you discover a worm with a flattened body. What one feature would suggest that it is a nemertean rather than a platyhelminth?

A complete gut with mouth and anus

According to the modern classification scheme, which animal would be a spider's closest relative?

A roundworm

The evolution of jointed appendages has made __________ very successful

Arthropods

An entomologist observed a locust sitting on a branch pumping its abdomen like an accordion. What is the insect most likely doing?

Assisting gas exchange in the tracheal system

Select the mismatched pair of Phylum Mollusca classes and their examples.

Bivalvia—snails

A snail in your garden and an oyster are quite different in appearance. What would be evidence to justify grouping them together?

Both have a mantle capable of secreting calcium carbonate.

In what way are a human and a crab similar?

Both have muscles that pull against rigid skeletons.

Members of the class _______, which include octopuses, squids, and nautiluses, are highly intelligent.

Cephalopoda

In their basic body plan, mollusks have a visceral mass covered with a soft epithelium and a muscular ____ that is used in locomotion.

Foot

The molluscan class ________ includes the snails and slugs.

Gastropoda

In terms of the number of species, the most successful class of arthropods is

Hexapoda.

A _________ is a circular or U-shaped ridge around the mouth, bearing either one or two rows of ciliated, hollow tentacles

Lophophore

Which one of the following incorrectly matches a molluscan group with a feature characterizing that group?

Nudibranchs—extensive gills in mantle cavity

Brachiopods develop as protostomes, but they show ______ cleavage.

Radial

Inside its beak an octopus has a rasping tongue that is used to tear apart food. Which gastropod structure is this analogous to?

Radula

Annelids are characterized by serial ________.

Segmentation

In many arthropods, body segments have become fused into functional groups called _____.

Tagmata

Pinworm is a nematode parasite that lives in the human rectum, and causes itching in the anal area. What best explains the itching symptom?

The itching induces the person to scratch, helping to spread the parasite to another person.

Elephantiasis is a human disease that is caused by a parasitic nematode that lives in the circulatory system. What causes the massive swelling of tissue that has given the disease its name?

The worms block the lymph vessels which causes the swelling.

Barnacles are sessile filter feeders but unlike bivalves they have internal fertilization. How do they solve this problem?

They are hemaphrodites with especially long penises.

Many parasitic flatworms have complex lifecycles involving several host organisms. For Asian liver flukes, humans are the final host. What would result if humans were not available for a population of Asian liver flukes?

They could not reproduce.

A spider and an insect are both arthropods, but they have some different characteristics. Choose the descriptions that are true for BOTH a spider and an insect. Check all that apply

They have an open circulatory system. They have a chitinous exoskeleton. They molt. They are members of Ecdysozoa.

Which feature is an evolutionary novelty of hexapods?

Wings

A marine biologist makes a presentation about crustaceans to your biology class. He explains that he has recently received an NSF grant to study sessile crustaceans. You are only aware of one group of sessile crustaceans. This crustacean must be

a barnacle.

A marine biologist visits your biology class and begins his talk entitled, "Life as a Trochophore." A friend seated next to you asks, "What is a trochophore?" You explain that a trochophore is

a term used to describe a larval form of either the phylum Mollusca or Annelida.

The medicinal leech, once used to withdraw "unhealthy" blood from patients, produces ____________ to ensure blood flow from the host?

anticoagulants

In some arthropods tagmatization has produced a combination of head and thorax known as a

cephalothorax.

Members of the phyla Annelida and Mollusca belong to the spiralian group Lophotrochozoa because they both possess a ______________ and a have marine representatives that undergo a ciliated larvae stage called a _______________.

coelom; trochophore

Which of the following organs of cephalopods resemble those of the vertebrates?

eyes

Rotifers are often called wheel animals because they are radially symmetrical.

false

The scolex of a tapeworm contains the mouth and the anterior neural ganglia.

false

Chelicerae function as

fangs or pincers.

The arthropods are the most successful group of animals; several key features explain their success. Check all of the features that one would use to classify members into this phylum.

growth takes place through ecdysis a rigid exoskeleton made of chitin jointed appendages segments specialized into functional tagmata

A biologist has been studying a mollusk that does not have a shell. It lives in the marine environment. Of the examples given below, which one did the biologist study?

octopus

Compound eyes are composed of independent visual units called

ommatidia.

Which one of the following insect organ systems has placed the greatest limitation on their body size?

respiratory system

The partitions that separate the segments of the annelid body are known as

septa.

In arthropods, locomotion is accomplished by muscles that work against

the exoskeleton.

Examples of mollusks that live on land are the Multiple Choice

snails and slugs.

An invertebrate biologist is conducting research with crabs. Her interest is ecdysis. This implies that she studies

the molting process.