Deck 20: Crustaceans

Question 1

The most accurate explanation of the management of nitrogenous wastes and ion balance in the crayfish is

A)the nitrogenous waste of crustaceans is excreted by the green glands and ion diffusion takes place by diffusion across thin areas of cuticle and the gills.
B)both ion balance and elimination of nitrogenous wastes is managed by the green glands.
C)hydrostatic pressure in the green glands forces fluid into the hemocoel and both ions,and nitrogenous wastes diffuse across thin areas of cuticle and the gills.
D)None of the choices is correct.
E)the nitrogenous waste of crustaceans is excreted by diffusion across thin areas of cuticle and the gills,while the so-called excretory organs regulate ion composition of the hemolymph.

Answer 1

E

Question 2

The "bailer" of a crayfish that draws water over the gill filaments is a part of the

A)second maxillae.
B)caudal furca.
C)third maxilliped.
D)first walking leg.
E)first swimmeret.

Answer 2

A

Question 3

How do crustacea differ from other arthropod groups?

A)They possess a telson tail
B)Only crustaceans have two pairs of antennae
C)Only crustaceans have chitinous exoskeletons
D)Only Crustacea possess a two-part body plan of cephalothorax and abdomen
E)A hemocoel is only found in Crustacea

Answer 3

B

Question 4

The generalized appendage of a crustacean has a basal portion or protopod that has a lateral ______ and a medial _________.

A)epiproct,underproct
B)flexor,extensor
C)exopod,endopod
D)endite,exite
E)tergum,sternum

Question 5

Which is a correct association of pigment and function in an arthropod compound eye?

A)Strong light-distal retinal pigment disappears
B)Strong light-each ommatidium is shielded from the others and sees only a limited area
C)Strong light-distal and proximal pigments separate
D)Dim light-each ommatidium is shielded from the others and sees only a limited area
E)Dim light-distal and proximal pigments fuse

Question 6

If crayfish are raised in a very clean aquarium that only has iron filings in the floor,and they are allowed to go through several molts so that an iron filing is now serving as a statolith,what would be the effect of a large magnet suspended above the aquarium?

A)There would be no effect at all.
B)The crayfish would swim sideways.
C)The crayfish would swim upside down.
D)The crayfish would be unable to detect food.
E)The crayfish would be blind.

Question 7

The various specialized body structures along the body of Malacostracans are thought to be derived from a common biramous appendage,which suggests

A)serial homology.
B)telsonization.
C)arthropodization.
D)analogous homology.
E)convergent evolution.

Question 8

The major body space in arthropods is the

A)coelom.
B)pseudocoelom.
C)hemocoel.
D)blastocoel.
E)telson.

Question 9

The segments of crustaceans are covered with a dorsal plate or _____________ and a ventral plate or ______________.

A)epiproct,underproct
B)flexor,extensor
C)endopod,exopod
D)endite,exite
E)tergum,sternum

Question 10

Crustacea are biramous,meaning they possess

A)a telson tail.
B)two large pincers.
C)two pair of antennae.
D)jointed appendages having two branches.
E)a body divided into two regions,the cephalothorax and abdomen.

Question 11

Medial and lateral processes on a crustacean limb are called __________ and __________ respectively.

A)epiprocts,underprocts
B)flexors,extensors
C)exopods,endopods
D)endites,exites
E)terga,sterna

Question 12

By lining up all the crayfish appendages,you would find that they possess

A)two pairs of abdominal swimmerets that are different in males and females.
B)a telson tail.
C)two large pincers.
D)two branches on all appendages.
E)All of the choices listed are crayfish appendages.

Question 13

The respiratory apparatus of a crayfish is

A)a set of gills under the carapace.
B)book lungs inside the carapace.
C)a set of gills along the underside of the tail.
D)tracheal tubes throughout the body.
E)a cluster of alveoli under the tail.

Question 14

Since the hemolymph of crustaceans leaves the heart by arteries,why is it considered an open rather than a closed system?

A)The hemolymph lacks any respiratory pigments.
B)The hemolymph flows through the hemocoel and returns via venous sinuses rather than enclosed veins.
C)The heart does not pump hemolymph but it moves by ciliary action instead.
D)The arteries "dead end" and the hemolymph must backflow through the arteries.
E)The hemolymph lacks any respiratory function.

Question 15

The first pair of walking legs in a crayfish,lobster,crab,and their relatives,that is enlarged with a terminal claw is the

A)protopodite.
B)statocyst.
C)cheliped.
D)pedipalp.
E)exopodite.

Question 16

The nerves of the eyes and the two pairs of antennae connect to the

A)statocyst.
B)supraesophageal ganglion.
C)subesophageal ganglion.
D)thoracic ganglion.
E)antennal glands.

Question 17

The tail fan of many malacostracans is

A)the rostrum.
B)the postcarapace.
C)the endopod.
D)a combination of uropods and telson.
E)a fusion of the last biramous appendages.

Question 18

The green glands form an effective "flood control" device in the freshwater crayfish by

A)forming a dilute,low-salt urine to unload the water that diffuses into the crayfish body.
B)forming a high-salt urine to unload the high salt built up in the crayfish body.
C)keeping the urine isosmotic to the blood.
D)keeping the interior hemocoel dry.
E)producing extra sodium and chloride ions to maintain the ionic balance.

Question 19

The photoreceptor cells in the crustacean compound eye are called

A)statocysts.
B)statoliths.
C)tactile hairs.
D)gastroliths.
E)ommatidia.

Question 20

What is the function of the green glands in the crayfish?

A)Secrete fluids to aid digestion
B)Increase oxygen absorption for respiration
C)Sensing vibrations in water
D)Reproduction
E)Excretion

Question 21

Marine crustaceans that are sessile,secrete calcareous plates and filter-feed are

A)ostracods.
B)barnacles.
C)copepods.
D)decapods.
E)isopods.

Question 22

The dorsal cuticle of the head of many crustaceans extends posteriorly to form a covering called the ___________________.

Question 23

Most appendages of crustaceans are two-branched,or _____________________.

Question 24

The organ in crayfish that functions in ion and water regulation and,to some extent,excretion is the ________ _________.

Question 25

The procuticle of crustaceans is often impregnated with __________________.

Question 26

Molting and subsequent ecdysis in crustaceans

A)involves production of a new cuticle and shedding of the old one.
B)is initiated by a stimulus perceived by the central nervous system.
C)involves a molt-inhibiting hormone produced by the X-organ of the eye stalk,and a molting hormone produced by the Y-organs near the mandibles.
D)cues on stimuli such as day length,temperature,or humidity.
E)All of the choices are correct.

Question 27

The appendages of a crayfish are examples of serial ___________________.

Question 28

When the juvenile that hatches from an egg resembles a miniature adult,the development is described as __________________.

Question 29

Androgenic glands in the amphipod function to

A)regulate ion balance.
B)stimulate expression of male characteristics.
C)control pigmentation for camouflage.
D)secrete digestive fluids.
E)control ecdysis.

Question 30

A characteristic unique to Crustacea is the possession of two pairs of _______________.

Question 31

The oldest ancestral and most widely-occurring larva in the Crustacea is

A)a juvenile resembling the adult.
B)the trochophore.
C)the veliger.
D)the nauplius.
E)a planula.

Question 32

Water fleas,which belong to the branchiopodan suborder ____________,often reproduce by parthenogenesis.

Question 33

A small group of hermaphroditic crustaceans that is unique in discharging both eggs and sperm through a common duct is the

A)maxillopoda.
B)cirripedia.
C)cephalocarida.
D)decapoda.
E)remipedia.

Question 34

The major body space in arthropods is called the ______________.

Question 35

Position sensors in the base of the first antennae of crayfishes are called _______________.

Question 36

The process which culminates with arthropods regularly shedding their exoskeleton because it has become too small for the growing body is called ___________________________.

Question 37

The group of Crustacea with the most ancestral features,including a long trunk with fairly uniform appendages,is the

A)maxillopoda.
B)cirripedia.
C)isopoda.
D)decapoda.
E)remipedia.

Question 38

Crustaceans have better-developed sense organs than do the annelids because they have _______ ________,delicate projections of cuticle distributed over the body,and especially the mouthparts.

Question 39

The order that has been successful invading terrestrial environments is the

A)amphipoda.
B)euphausiacea.
C)cladocera.
D)decapoda.
E)isopoda.

Question 40

The two joints of the protopod are the ______ ______ and medial endopod.

Question 41

How does the statocyst work to communicate position to the crayfish?

Question 42

The most diverse class of crustaceans is the __________________.

Question 43

What is the evidence that the major tagmata in crustaceans are not homologous?

Question 44

The excretory antennal glands in decapods are also called ________ _________.

Question 45

The individual units of compound eyes in crustaceans are called ________________.

Question 46

Why is the adaptive diversification of the Crustacea so great while that of other groups,such as the Annelida so much less?

Question 47

Discuss the evolutionary significance of the serial homology of crustacean appendages.

Question 48

Based on a count of individual organisms,a species in the copepod genus Calanus is likely the most abundant animal in the world.What features do copepods possess and what environmental factors contribute to this record status?

Question 49

The ancestral larval form of crustaceans is the __________.

Question 50

Describe the sequence of events that occur during molting and ecdysis in a crayfish and explain why a "soft craw" is vulnerable until it has hardened its shell.

Question 51

Why are barnacles considered crustaceans when they are anchored in one place as adults?

Question 52

Both clams and crabs are referred to in common terminology as "shellfish." However,zoologists do not consider them to be closely related.Provide a contrasting list of the differences between the crustacean decapods and the molluscan bivalves.

Question 53

Discuss how modulation in expression of the Distal-less gene determines the location of distal ends of arthropod limbs.What is the significance of this?

Question 54

In crustaceans,the molt-inhibiting hormone is produced in the ______________.

Question 55

Crustaceans and molluscs of course do have a common ancestor at some point.Draw a reasonable phylogeny that includes the molluscs,annelids and arthropods including the crustacea,and describe the distinguishing features on each branch.There are several legitimate phylogenies.

Question 56

How do the various pigments in the ommatidium work to provide images of variable field of vision or a continuous image in variable degrees of light and dark?

Question 57

Explain why pentastomids were placed in Ecdysozoa.

Question 58

Crustaceans are often referred to as the "insects of the sea." This is partially because crustaceans are so abundant in the sea,as insects are on land,and because insects never successfully invaded the marine environment.Discuss why crustaceans 1)are so abundant in the ocean,and 2)why they did not radiate extensively into terrestrial environments.

Question 59

In the parasitic barnacle order Rhizocephala,the larvae metamorphose into a _______ stage that injects cells into the hemocoel of the crab that grows into root-like processes throughout the crab body.