Deck 19: Trilobites, Chelicerates, and Myriapods

Question 1

The arthropods

A)make up more than three-fourths of all the known species of animals.
B)are more widely and more densely distributed throughout the world than members of any other phylum of animals.
C)are segmented eucoelomate protostomes with well-developed organ systems.
D)are limited in size and generally are smaller than 60 centimeters in length.
E)All of the choices are correct.

Answer 1

E

Question 2

The term "myriapod" includes

A)all arthropods,gastropods,and brachiopods.
B)just the millipedes and centipedes.
C)insects and their ancestors.
D)all arthropods except arachnids and crustaceans.
E)centipedes,millipedes,pauropods and symphylans but not insects.

Answer 2

E

Question 3

You could collect a sea spider

A)as an ectoparasite on a whale.
B)grazing in kelp beds.
C)from intertidal zones to over 6000 meters deep,especially in polar waters.
D)as an endoparasite in the gut of echinoderms.
E)in underwater webs in coral reefs.

Answer 3

C

Question 4

Members of the class Arachnida have

A)a cephalothorax and abdomen.
B)antennae.
C)mandibles.
D)five pairs of walking legs.
E)All of the choices are arachnid features.

Question 5

How do spiders eat?

A)A spider mashes and manipulates food with its fangs so it can be swallowed whole.
B)Food is soaked into silk threads which are then consumed.
C)Food is partly digested externally and the nutritive juices are sucked into the stomach.
D)Food is stored in a crop and ground up in a gizzard.
E)Food is swallowed whole.

Question 6

Which arachnid has a bite or sting that is neurotoxic and causes paralysis?

A)Scorpion
B)Brown recluse spider
C)Black widow spider
D)All arachnids have such a toxin and are dangerous if large enough to bite us
E)No arachnid has a dangerous neurotoxic bite

Question 7

Spider silk

A)is very strong but cannot be stretched without breaking.
B)is only produced by those orb web spiders that form webs to catch insects.
C)is formed as solid coiled threads internally that can be uncoiled and used whenever needed.
D)is used differently by different spider species.
E)All of the choices are correct.

Question 8

What makes the shell of a lobster so hard?

A)It contains chitin which is hard and inflexible.
B)The procuticle is impregnated with calcium salts.
C)It is due solely to a tanning process.
D)The procuticle and epicuticle are laminated.
E)The shell protein contains more lipid.

Question 9

Arthropods are successful because they have

A)a very efficient respiratory system.
B)highly developed sensory organs.
C)reduced competition through metamorphosis.
D)a protective exoskeleton that allows both protection and mobility.
E)All of the choices are correct.

Question 10

Chelicerate arthropods possess

A)pedipalps.
B)antennae.
C)mandibles.
D)three pairs of walking legs.
E)All of the choices are chelicerate features.

Question 11

The excretory system of insects and spiders works by

A)excreting wastes across the digestive system membrane.
B)active transport of just the waste molecules across the tubules.
C)transport of all ions and solutes across the tubule and retrieval of water and useful ions in the rectum.
D)excretion of only ions and wastes in the rectum.
E)packaging and sealing off toxic wastes until the organism dies.

Question 12

The correct order for layers of ectoskeleton from outside to inside is

A)endocuticle-epicuticle-exocuticle.
B)endocuticle-exocuticle-epicuticle.
C)exocuticle-endocuticle-epicuticle.
D)epicuticle-exocuticle-endocuticle.
E)exocuticle-epicuticle-endocuticle.

Question 13

Sea spiders

A)are extinct.
B)feed on fluids of soft-bodied animals such as cnidarians.
C)resemble crustaceans.
D)have an unusually large abdomen.
E)are marine arachnid spiders.

Question 14

Eurypterids

A)resembled insects.
B)are extinct.
C)are called sea spiders.
D)were very small aquatic scorpions.
E)were huge ancient scorpions that wandered on land.

Question 15

Spiders and insects have an excretory system composed of

A)permeable surface cuticle.
B)enclosed book lungs.
C)flame cells.
D)green glands.
E)malpighian tubules.

Question 16

A male spider inseminates a female spider by

A)normal abdomen to abdomen mating.
B)external fertilization where a male spider dances a female over a spermatophore packet.
C)injecting sperm with his pedipalps and then rapidly retreating before being eaten.
D)transferring sperm via silk.
E)avoiding the dangerous female spider altogether and fertilizing the eggs after they are laid in an egg case.

Question 17

Spiders breathe by means of

A)gills.
B)diffusion across the soft cuticle.
C)an extensive system of tracheae more complex than is found in insects.
D)book lungs or primitive tracheae.
E)coxal glands.

Question 18

Trilobites exist today as

A)freshwater dwellers.
B)terrestrial crustaceans.
C)aquatic insects.
D)horseshoe crabs.
E)fossils only;they are all extinct.

Question 19

Arthropods are

A)carnivorous.
B)herbivorous.
C)omnivorous.
D)both carnivorous and herbivorous.
E)All of the choices are correct.

Question 20

Horseshoe crabs

A)are,like their relatives the trilobites and eurypterids,now extinct.
B)are poisonous to humans.
C)live in freshwater habitats.
D)have a long,spine-like telson.
E)are adult forms of trilobites.

Question 21

The mites and ticks carry their mouthparts on a little anterior projection called the

A)hypostome.
B)rostrum.
C)capitulum.
D)pedipalp.
E)pectin.

Question 22

Chelicerates have six pairs of appendages that include a pair of pedipalps,four pairs of walking legs,and a pair of ____________________.

Question 23

For scorpions,mating is particularly risky for the male since the female can eat the male.Therefore,the male scorpion

A)uses the same procedure as male spiders.
B)holds the females pincers in a "dance" position,deposits a spermatophore on the ground and dances her over it.
C)transfers a spermatophore from between his body segments directly into hers.
D)fertilizes her by hypodermic insemination where the sperm is injected inside her body cavity.
E)still uses regular mating since this copulatory position keeps her facing away safely.

Question 24

You find a white,soft-bodied myriapod in the soil in a flower pot.It has long antenna but lacks eyes and fang-like claws.It most likely is a

A)pauropod.
B)symphylan.
C)centipede.
D)millipede.
E)None of the choices is correct.

Question 25

You are given a large tropical millipede to raise in a humid terrarium lined with soil and leaf litter.What should you feed it?

A)Insects
B)Sliced apples and dead soft plant tissues
C)Freshly cut wood
D)Fresh meat or dog food
E)All of the choices would be food for a millipede

Question 26

Male sea spiders have a subsidiary pair of legs called _____________ on which they carry developing eggs.

Question 27

Reproduction in millipedes is

A)external in moist moss or soil.
B)internal and the young are born live.
C)internal and the eggs are abandoned under rocks and rotting logs.
D)internal and eggs are laid in a nest and guarded by the female.
E)by asexual segmentation.

Question 28

Scabies mite (Sarcoptes scabei)infections

A)are harmless and live in human hair follicles.
B)cause intense itching.
C)are the causative agent of "chiggers."
D)are fatal infections because they carry Lyme disease.
E)are fatal infections because they carry Rocky Mountain Spotted Fever.

Question 29

Members of the subphylum ________________ were abundant during the Cambrian period.

Question 30

The Acari

A)have a distinct head,thorax,and abdomen.
B)are of great economic and medical importance.
C)are a limited and well known order of about 2,000 species.
D)are all terrestrial.
E)All of the choices are correct.

Question 31

Centipedes

A)are herbivorous.
B)have poison claws.
C)have five pairs of legs.
D)use gills for respiration.
E)are parthenogenetic and always oviparous.

Question 32

Scorpions

A)feed during the day.
B)are most common in the temperate areas of the world.
C)are docile animals that,in spite of their reputation,cannot harm humans.
D)are sensitive to surface waves produced by movement on the ground.
E)All of the choices are correct.

Question 33

Which is NOT a correct association of scorpion structures and functions?

A)Pectines-tactile organs to explore the ground
B)Spermatophore-a packet of sperm
C)Chelicerae-large six-jointed pincers
D)Cephalothorax-bears the appendages
E)Postabdomen-bears a tail with sting

Question 34

What carries the bacteria that cause Lyme disease?

A)Dermacentor sp
B)Boophilus annulatus
C)Trombicula sp
D)Demodex sp
E)Ixodes sp

Question 35

As the arthropod ancestors underwent "arthropodization,"

A)their circulatory system became closed.
B)their hemocoel took on a new function as a hydrostatic skeleton.
C)there was an expansion of surfaces for respiration and excretion.
D)Intersegmental septa became unnecessary.
E)a closed circulatory system became necessary.

Question 36

Pauropods lack

A)eyes.
B)tracheae.
C)a circulatory system.
D)spiracles.
E)All of the choices are lacking in pauropods.

Question 37

The tough,resistant,nitrogenous polysaccharide in the cuticle of arthropods is ________________.

Question 38

The millipedes

A)bear two pairs of legs on most body segments.
B)are very beneficial because they feed on insects.
C)are more active than centipedes because they have more legs.
D)have flattened bodies in contrast to centipedes.
E)lack spiracles and tracheae and therefore differ from centipedes.

Question 39

Groups of segments fused or combined into functional groups are called __________.

Question 40

You would be most likely to find a pauropod if you examined

A)the fur of a mammal,since they are parasites.
B)under a rock in a stream.
C)moist soil,leaf litter,or decaying debris.
D)inside the juicy tissues of a host plant.
E)an intertidal pool.

Question 41

__________ differ from all other arachnids in having complete fusion of the cephalothorax and abdomen.

Question 42

During mating in spiders,the male inserts his ____________ into the genital opening of the female.

Question 43

Most spiders feed on _________________________.

Question 44

Some mites,such as the _______ ________ or family Tetranychidae,are very destructive to plants.

Question 45

Why is the formation of the cuticular exoskeleton with jointed appendages considered central to the success of arthropod diversity?

Question 46

What features constitute "arthropodization" and what evidence exists that these features evolved once rather than several times independently?

Question 47

There are animal groups that have smaller individuals than arthropods and they have a few hundred or a few thousand species.And there are animal groups that contain much larger organisms,and they have a few hundred or a few thousand species.Why do the intermediate-sized arthropods have over a million species?

Question 48

Arthropodan cephalization is pronounced.Would this have anything to do with tagmatization? If an organism is highly cephalized does it always exhibit tagmatization? If an organism exhibits tagmatization,is it always highly cephalized?

Question 49

Another name for the harvestman is ________ ________.

Question 50

The excretory system of spiders and insects is a structure known as ________ ________.

Question 51

The arthropodan cuticle is not entirely hardened.Why not (think of the need to be mobile and flexible)?

Question 52

The mouthparts of ticks and mites are carried on an anterior projection called the __________.

Question 53

Four classes of myriapods are Chilopoda,Pauropoda,Symphyla and _____________.

Question 54

The exoskeleton is a "suit of armor" with muscles attached from inside.Yet the exoskeleton must be periodically shed.Describe the layers of the exoskeleton and the process of molting.

Question 55

Tactile organs on the ventral side of scorpions are ________________.

Question 56

Two poisonous spiders in the United States that are dangerous to humans are the black widow and the ______ _______.

Question 57

What is the evolutionary significance of arthropodization? Aren't tetrapods such as humans as successful as arthropods? Explain your reasoning.

Question 58

During the process of "arthropodization," the role of the coelomic compartments as a _________ ________ was lost.

Question 59

The parasitic or micropredatory arachnids belong to the order ________.

Question 60

Many millipedes defend themselves by secreting toxic or repellant fluids from _________ __________.

Question 61

There is a hypothesis that euryterid predation on early fish induced the selection for armor in these vertebrates.What kind of evidence would you require to show that there might be a causation here,rather than just a correlation in the fossil record?

Question 62

What are the various uses for spider's silk?

Question 63

Why are the Opiliones considered to be in a clade with the scorpions and not so closely aligned with the Acari?

Question 64

Discuss the ecological position of the spiders as a group.

Question 65

Insects are basically small creatures.How does a small organism retard water loss? Discuss both structural and physiological mechanisms.

Question 66

Discuss the importance of cuticular mechanoreceptors in the spiders.

Question 67

Outline the apparent reasons why arthropods have achieved such incredible diversity and abundance.

Question 68

Discuss the various functions of the exoskeleton.

Question 69

Discuss features of ticks that make them such excellent vectors of human arthropod-borne diseases.

Question 70

Do you believe our current understanding of the phylogeny of the arthropods is the correct one? Why or why not?

Question 71

Describe the bite of the chigger mite.How long are the nymphs actually attached,and why is it that some people have such intense reactions to their bites yet others have none?

Question 72

What is the evidence that suggests pycnogonids are more closely related to crustaceans than to other arthropods? Why is this evidence contrary to molecular evidence that suggests otherwise?