Question 1

The common ancestor of the protostomes had a coelom.What does this suggest?

Accepted Answer

D

Question 2

Which mollusk group can be described as having several calcium carbonate plates along their dorsal side?

Accepted Answer

Chitons have several calcium carbonate plates along their dorsal side, which overlap like shingles on a roof. Bivalves typically have two shells that are hinged together, gastropods have one coiled shell, and cephalopods have a soft-bodied mantle with a hard external shell (in some species).

Question 3

The body cavity type for arthropods and mollusk can best be described as _____.

Accepted Answer

Arthropods and mollusks have a reduced coelom, as their primary body cavity is a hemocoel, which is part of an open circulatory system.

Question 4

When considering the wormlike phyla within the protostomes,which feature is most useful in distinguishing groups?

Accepted Answer

Feeding structures or mouthparts are a key feature used to distinguish the various wormlike phyla within protostomes, such as Annelida, Nematoda, and Platyhelminthes. The type of body cavity (A) and presence or absence of a hemocoel (B) are less helpful in distinguishing these groups, as these features can vary within each phylum or even within different species in the same phylum. While a hydrostatic skeleton (D) is present in some wormlike phyla, it is not a defining characteristic that can distinguish between them.

Question 5

If you wanted to identify an unfamiliar protostome with a limbless,wormlike body,which characteristic would not be helpful in differentiating one species from another?

Accepted Answer

A hydrostatic skeleton is a common feature among many wormlike organisms and does not provide specific information to differentiate between species.

Question 6

What do all the Lophotrochozoa phyla discussed in the text have in common?

Accepted Answer

The answer of What do all the Lophotrochozoa phyla discussed...

Question 7

Which of the following do Nematoda and Arthropoda have in common?

Accepted Answer

Both Nematoda and Arthropoda grow by shedding their outer covering, which is known as molting.

Question 8

The presence of a lophophore in a newly discovered species would suggest which of the following?

Accepted Answer

A lophophore is a specialized feeding structure used for suspension feeding, indicating the species is likely a suspension feeder.

Question 9

You find an animal and believe it is a new species of Nemertean.Which line of evidence would support your hypothesis?

Accepted Answer

Nemerteans are a phylum of worms that are characterized by their proboscis, which is a long, muscular tube that they use to capture prey.

Question 10

Which of these mollusk features substitutes for the coelom by providing a space for organ development and circulation of bodily fluids?

Accepted Answer

The answer of Which of these mollusk features substitutes for...

Question 11

Here is a statement from the text:
"The ability to live in terrestrial environments evolved independently in arthropods (at least twice),mollusks,roundworms,and annelids." What logical conclusion would you make from this statement?

Accepted Answer

The statement mentions that the ability to live in terrestrial environments evolved independently in multiple groups, suggesting that a common aquatic ancestor gave rise to these groups.

Question 12

Among protostomes,which morphological trait has shown the most variation?

Accepted Answer

The type of body cavity has shown the most variation among protostomes. Some have a true coelom, some have a pseudocoelom, and some have no body cavity (acoelomate). The other traits listed (type of symmetry, number of embryonic tissue types, and direction of gastrulation) are more consistent within the protostome group.

Question 13

Which one of these mollusk groups can be classified as suspension feeders?

Accepted Answer

Bivalves, such as clams and oysters, are known as suspension feeders because they filter organic material from the water that passes through their gills. They do not actively hunt or scavenge for food like other mollusks, but rely on filtering small particles from the water for sustenance.

Question 14

The protostome developmental sequence arose just once in evolutionary history,resulting in two main subgroups Lophotrochozoa and Ecdysozoa.What does this finding suggest?

Accepted Answer

The fact that the protostome developmental sequence arose just once in evolutionary history and resulted in two main subgroups (Lophotrochozoa and Ecdysozoa) suggests that the division of these two groups occurred after the protostome developmental sequence appeared. This implies that the protostomes are a monophyletic group. Option A is incorrect because it suggests that the two subgroups have a common ancestor that was a deuterostome, which is not true. Option B is incorrect because it suggests that the protostomes are a polyphyletic group, which contradicts the fact that the protostome developmental sequence arose just once in evolutionary history. Option D is incorrect because it refers only to the lophotrochozoans, whereas the question is about the protostomes as a whole.

Question 15

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

The presence of cilia in the larvae for feeding and locomotion is a characteristic of flatworms, not roundworms. This indicates that the new species is more closely related to flatworms than roundworms.

Question 16

Which of the following attributes is true for both arthropod exoskeletons and mollusk shells?

Accepted Answer

Both arthropod exoskeletons and mollusk shells help retain moisture in terrestrial habitats, providing protection against desiccation.

Question 17

The major evolutionary split of protostome animals was based on _____.

Accepted Answer

The major evolutionary split of protostome animals is based on the way that the organism grows, distinguishing between ecdysozoans, which molt their exoskeleton, and lophotrochozoans, which grow incrementally.

Question 18

Figure 33.1
 
-Refer to Figure 33.1.Suppose new molecular analyses indicated that the phylum Annelida had diverged from the arthropod lineage after Onychophora and Tardigrada.What would this imply about protostome evolution?

Accepted Answer

Segmentation evolved only once within protostomes; the annelid lineage gained and then lost the ability to molt.

Question 19

A _____ is comprised of a mouth surrounded by ciliated tentacles.

Accepted Answer

A lophophore is a ring of ciliated tentacles that surround the mouth of certain animals, such as brachiopods, bryozoans, and phoronids. This structure is used for feeding and capturing small particles in the water.

Question 20

In adult arthropods,the hemocoel performs which of the following functions?

Accepted Answer

The hemocoel in adult arthropods is a primary body cavity that provides space for internal organs to grow and function, as it is part of their open circulatory system.

Quiz 33: Protostome Animals