Question 1

The photoreceptor cells in the crustacean compound eye are called

Accepted Answer

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

Question 2

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?

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The answer of Discuss how modulation in expression of the...

Question 3

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

Accepted Answer

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

Question 4

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

Accepted Answer

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

Question 5

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.

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The answer of Both clams and crabs are referred to...

Question 6

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

Accepted Answer

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

Question 7

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

Accepted Answer

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

Question 8

Crustacea are biramous,meaning they possess

Accepted Answer

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 9

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

Accepted Answer

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 10

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?

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The answer of How do the various pigments in the...

Question 11

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

Accepted Answer

The answer of In crustaceans,the molt-inhibiting hormone is produced in...

Question 12

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

Accepted Answer

The answer of What is the evidence that the major...

Question 13

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?

Accepted Answer

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 14

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

Accepted Answer

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.

Question 15

The respiratory apparatus of a crayfish is

Accepted Answer

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 16

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

Accepted Answer

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 17

The major body space in arthropods is called the ______________.

Accepted Answer

The answer of The major body space in arthropods is...

Question 18

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

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The answer of The organ in crayfish that functions in...

Question 19

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

Accepted Answer

The answer of When the juvenile that hatches from an...

Question 20

How do crustacea differ from other arthropod groups?

Accepted Answer

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

Exam 20: Crustaceans