Question 1

A brachiopod can be distinguished from a bivalve by the presence of

Accepted Answer

A brachiopod can be distinguished from a bivalve by the presence of a lophophore, which is a feeding structure that consists of tentacles with cilia that are used for suspension feeding. Bivalves do not have a lophophore, but instead use their gills for filter feeding. Both brachiopods and bivalves have two hinged shells, and neither have a distinct head or a digestive system with a separate mouth and anus.

Question 2

You find what you believe is a new species of animal.Which of the following characteristics would enable you to argue that it is more closely related to a flatworm than it is to a roundworm?

Accepted Answer

A flatworm is an acoelomate, meaning it lacks a true coelom or body cavity while a roundworm is a pseudocoelomate, meaning it has a body cavity that is partially lined with mesoderm. Therefore, if the new species also lacks a coelom, it is more closely related to a flatworm than a roundworm. The other characteristics (A, C, and D) do not distinguish between flatworms and roundworms.

Question 3

The heartworms that can accumulate within the hearts of dogs and other mammals have a pseudocoelom,an alimentary canal,and an outer covering that is occasionally shed.To which phylum does the heartworm belong?

Accepted Answer

Heartworms belong to the phylum Nematoda, which are characterized by a pseudocoelom, an alimentary canal, and an outer covering that is occasionally shed. Platyhelminthes (A) are flatworms, Arthropoda (B) are insects, and Annelida (E) are segmented worms, none of which have the same characteristics as heartworms. Acoela (D) are a subgroup of flatworms and also do not fit the characteristics of heartworms.

Question 4

Nematode worms and annelid worms share which of the following features?

Accepted Answer

The answer of Nematode worms and annelid worms share which...

Question 5

A student observes a wormlike organism crawling about on dead organic matter.Later,the organism sheds its outer covering.One possibility is that the organism is a larval insect (like a maggot).However,it might be a member of the phylum ________,and one way to distinguish between the two possibilities is by looking for ________.

Accepted Answer

The answer of A student observes a wormlike organism crawling...

Question 6

A terrestrial mollusc without a shell belongs to which clade?

Accepted Answer

Terrestrial molluscs without a shell are typically gastropods, such as slugs and snails. Chitons, bivalves, and cephalopods all have some form of shell.

Question 7

What would be the most effective method of reducing the incidence of blood flukes in a human population?

Accepted Answer

Blood flukes require freshwater snails for part of their life cycle, so reducing the snail population would directly impact the incidence of blood flukes in a human population. A, C, D, and E are important measures for preventing other diseases, but do not have a direct impact on blood flukes.

Question 8

Which of the following organisms would you expect to have the largest surface-area-to-volume ratio? Assume that all of the following are the same total length.

Accepted Answer

A platyhelminth, also known as a flatworm, has a flattened body shape that leads to a high surface-area-to-volume ratio. This is because their body volume is relatively small compared to their surface area. In contrast, mollusks, annelids, and arthropods have more cylindrical body shapes with a larger volume relative to their surface area.

Question 9

If a lung were to be found in a mollusc,where would it be located?

Accepted Answer

Mollusks that have lungs will have them located in the mantle cavity. The mantle cavity is a chamber that is located between the body of the mollusk and the mantle, which is a fold of tissue that covers the organs. The gills are also located in the mantle cavity.

Question 10

While sampling marine plankton in a lab,a student encounters large numbers of fertilized eggs.The student rears some of the eggs in the laboratory for further study and finds that the blastopore becomes the mouth.The embryo develops into a trochophore larva and eventually has a true coelom.These eggs probably belonged to a(n)

Accepted Answer

The presence of a blastopore that becomes the mouth, development into a trochophore larva, and the development of a true coelom are all characteristic of molluscs. Therefore, these eggs likely belong to a mollusc.

Question 11

Which of the following is a characteristic of nematodes?

Accepted Answer

Nematodes have only longitudinal muscles, which allow them to wriggle and thrash about, but not move in a wave-like motion like other organisms with circular muscles.

Question 12

Infection with which parasite might cause excessive elasticity in human skeletal muscles?

Accepted Answer

Trichinella worms can cause a condition called trichinosis, which occurs when the larvae of the parasite invade skeletal muscle cells and form cysts. This can lead to inflammation, pain, and excessive elasticity in the muscles.

Question 13

Humans most frequently acquire trichinosis by

Accepted Answer

Trichinosis is a parasitic disease caused by the roundworm Trichinella spiralis. The most common way humans acquire it is by eating undercooked pork that contains the larvae of the worm.

Question 14

Planarians lack dedicated respiratory and circulatory systems because

Accepted Answer

Planarians have a gastrovascular cavity that serves as a respiratory and circulatory system, and none of their cells are far away from this cavity or from the external environment. Mesoderm is not necessary for the development of these systems, as seen in animals such as insects that lack mesoderm but still have specialized respiratory and circulatory systems. Flame bulbs are involved in excretion rather than respiratory or circulatory functions. The pseudocoelom does not play a major role in respiratory or circulatory functions.

Question 15

Parasitism is one of the most widespread life strategies ever to evolve.Which of the following is consistent with this finding?

Accepted Answer

Parasites that do not generally kill their hosts can feed on the same host throughout the host's normal life span and do not have competition from decomposers. This allows them to spend less energy and require fewer structural adaptations, as they do not need to constantly search for new hosts. Additionally, parasites may feed on only certain tissues or organs of their host, rather than all tissues, like predators do.

Question 16

Which mollusc clade includes members that undergo embryonic torsion?

Accepted Answer

Gastropods are the only mollusc clade that includes members that undergo embryonic torsion, which is a twisting of the body during development that results in the anus and mantle cavity being placed above the head. This unique characteristic is only found in gastropods, such as snails, slugs, and whelks.

Question 17

The larvae of many common tapeworm species that infect humans are usually found

Accepted Answer

The larvae of many common tapeworm species that infect humans, such as Taenia saginata and Taenia solium, are encysted in the muscles of animals, particularly cows and pigs. When humans consume undercooked meat from infected animals, they can become infected with the tapeworm larvae.

Question 18

Which of the following is found only among annelids?

Accepted Answer

A clitellum is a feature unique to annelids, particularly within the subclasses Oligochaeta (which includes earthworms) and Hirudinea (leeches). It secretes a cocoon for the eggs, distinguishing these creatures from others listed.

Question 19

A radula is present in members of which clade(s)?

Accepted Answer

Radula, a tongue-like organ with rows of teeth, is present in both chitons and gastropods. Bivalves lack a radula, and cephalopods have a modified radula known as a beak.

Question 20

How many of the following can be used to distinguish a nematode worm from an annelid worm?
1)type of body cavity
2)number of muscle layers in the body wall
3)presence of segmentation
4)number of embryonic tissue layers
5)shape of worm in cross-sectional view

Accepted Answer

The answer of How many of the following can be...

Quiz 33: An Introduction to Invertebrates