Question 1

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

Accepted Answer

A) The initial pore formed in the gastrula stage becomes the anus. 
B) They are suspension feeders. 
C) They grow by shedding their outer covering. 
D) They are lophotrochozoans. 
E) They have the same kind of unique,ciliated larvae.

Question 2

Figure 33.2
Use the following information when answering the corresponding question(s).
Many terrestrial arthropods exchange gases with their environments by using tracheae,tubes that lead from openings (called spiracles)in the animal's exoskeleton or cuticle directly to the animal's tissues.Some arthropods can control whether their spiracles are opened or closed;opening the spiracles allows the carbon dioxide produced in the tissues to travel down the tracheae and be released outside the animal.Klok et al.measured the carbon dioxide emitted over time (represented by VCO₂)by several species of centipedes.Figure 33.2 presents graphs of their results for two species,Cormocephalus morsitans and Scutigerina weberi.(C.J.Klok,R.D.Mercer,and S.L.Chown.2002.Discontinuous gas-exchange in centipedes and its convergent evolution in tracheated arthropods.Journal of Experimental Biology 205:1019-29. )
 
-Compare the graphs in Figure 33.2 of CO₂ emission for Cormocephalus morsitans and Scutigerina weberi.What hypothesis can you make about each centipede's habitat?

Accepted Answer

A) 
C) morsitans lives in a habitat that provides more carbon dioxide than does S.weberi. 
B) 
C) morsitans lives in a habitat with more predators than does S.weberi. 
C) 
C) morsitans lives in a colder habitat than does S.weberi. 
D) 
C) morsitans lives in a drier habitat than does S.weberi.

Question 3

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

Accepted Answer

A) the type of body cavity 
B) the presence or absence of a hemocoel 
C) feeding structures or mouthparts 
D) hydrostatic skeleton

Question 4

You find a multi-legged animal in your garden and want to determine if it is a centipede or a millipede.You take the animal to a university where a myriapodologist quickly tells you that you've found a centipede.Which of the following may have allowed her to make this distinction?

Accepted Answer

A) segmentation 
B) poison-filled glands 
C) the total number of legs 
D) egg-laying 
E) molting

Question 5

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

A) Segmentation evolved only once within protostomes. 
B) The annelid lineage gained and then lost the ability to molt. 
C) The annelid lineage gained and then lost jointed limbs. 
D) Segmentation evolved only once within protostomes;the annelid lineage gained and then lost the ability to molt. 
E) Segmentation evolved only once within protostomes;the annelid lineage gained and then lost jointed limbs.

Question 6

Which one of these groups does not molt?

Accepted Answer

A) Crustaceans 
B) Arthropods 
C) Mollusks 
D) Chelicerata 
E) Nematoda

Question 7

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

Accepted Answer

A) bivalves 
B) gastropods 
C) chitons 
D) cephalopods

Question 8

What is not true of all arthropods?

Accepted Answer

A) They metamorphose during development. 
B) They have jointed limbs. 
C) They grow by molting. 
D) They have segmented bodies. 
E) They have an exoskeleton or cuticle.

Question 9

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) what kind of mouthparts the organism had 
B) whether the organism metamorphosed into a different form 
C) whether the organism moved using a hydrostatic skeleton 
D) whether the organism's body was divided into segments

Question 10

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

Accepted Answer

A) They feed using lophophores,specialized ciliated structures. 
B) They have trochophore larvae,which swim with the aid of a ring of cilia. 
C) They have members that reproduce sexually and members that reproduce asexually. 
D) They grow by shedding an exoskeleton or cuticle.

Question 11

You find a wormlike animal while scuba diving and want to determine whether it is a nudibranch,a polychaete,or a turbellarian.Which of the following would allow you to definitively classify the organism into one of those categories?

Accepted Answer

A) bristle-like structures on tiny appendages 
B) a coelom 
C) the ability to swim 
D) bright coloration 
E) sexual reproduction

Question 12

In your laboratory,you examine a vial of freshwater from a local pond.You notice several unfamiliar small (less than one millimeter in length)animals and decide to study them.You observe that the animals have a coelom,eat microscopic food particles,reproduce by parthenogenesis,and offspring do not undergo any larval stages.What else would you expect to observe about this organism?

Accepted Answer

A) a corona 
B) a lophophore 
C) a scolex 
D) chaetae 
E) a mantle

Question 13

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

Accepted Answer

A) nature of the body cavity 
B) presence or degree of segmentation 
C) number of germ layers present in embryonic development 
D) method of feeding 
E) way that the organism grows

Question 14

Which of the following organisms would you expect to have the largest surface-area-to-volume ratio?

Accepted Answer

A) a rotifer 
B) a mollusk 
C) an annelid 
D) an arthropod 
E) a platyhelminth

Question 15

Figure 33.2
Use the following information when answering the corresponding question(s).
Many terrestrial arthropods exchange gases with their environments by using tracheae,tubes that lead from openings (called spiracles)in the animal's exoskeleton or cuticle directly to the animal's tissues.Some arthropods can control whether their spiracles are opened or closed;opening the spiracles allows the carbon dioxide produced in the tissues to travel down the tracheae and be released outside the animal.Klok et al.measured the carbon dioxide emitted over time (represented by VCO₂)by several species of centipedes.Figure 33.2 presents graphs of their results for two species,Cormocephalus morsitans and Scutigerina weberi.(C.J.Klok,R.D.Mercer,and S.L.Chown.2002.Discontinuous gas-exchange in centipedes and its convergent evolution in tracheated arthropods.Journal of Experimental Biology 205:1019-29. )
 
-Look at the graph for Scutigerina weberi (note the scale of the y-axis)in Figure 33.2.What is the best interpretation of these results?

Accepted Answer

A) The centipede had its spiracles open the entire time. 
B) The centipede had its spiracles closed the entire time. 
C) The centipede had its spiracles open when CO₂ emission peaked and closed when CO₂ emission was low. 
D) The centipede had its spiracles closed when CO₂ emission peaked and open when CO₂ emission was low.

Question 16

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

Accepted Answer

A) provides space for the internal organs to grow and function 
B) forms a cavity to protect the visceral mass of organs 
C) acts as a hydrostatic skeleton for mobility 
D) secretes the exoskeleton

Question 17

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

Accepted Answer

A) type of symmetry (bilateral vs.radial vs.none) 
B) type of body cavity (coelom vs.pseudocoelom vs.acoelom) 
C) number of embryonic tissue types (diploblasty vs.triploblasty) 
D) direction of gastrulation (protostome vs.deuterostome)

Question 18

Upon close inspection of movement in annelids and nematodes,you would notice an obvious difference.Nematodes tend to wriggle back and forth,while annelids tend to contract along their length as their girth swells and then thin out as they stretch.What anatomical feature explains this type of movement?

Accepted Answer

A) The annelids possess longitudinal muscle fibers that the nematodes lack. 
B) The nematodes lack circular muscle fibers. 
C) Nematodes lack a coelom. 
D) Annelids have a highly specialized nervous system capable of more complex movements.

Exam 33: Protostome Animals