Arthropods (Chelicerates, Myriapods, Crustaceans)

Question 1

What are the characteristics of the Clade Ecdysozoa?

Answer 1

1) Have a outer body covering called cuticle
2) Molt a cuticle
3) Coelomate and Pseudocoelomate body plans
4) Most constrained Metazoan body plans

Question 2

What are the characteristics of the Phylum Nematoda?

Answer 2

1) Most constrained body plan - hydrostatic pressure
2) Elastic cuticle contains pseudocoel under pressure
3) Only longitudinal muscles - move thru tight spaces
4) Free-living and parasitic

Question 3

What is the body plan of Phylum Nematoda?

Answer 3

Highly constrained (all look identical)

• Must swallow against hydrostatic pressure
• No respiratory structure limits size (long and skinny)

Question 4

How does the body plan of Nematodes affect reproduction?

Answer 4

Mostly dioecious with internal fertilization

-Form shelled eggs internally allows embryo to form its own high pressure

Question 5

How do Nematode parasites differ from Platyhelminthes parasites?

Answer 5

Platyhelminth absorb food through their tegument

Nematode parasites must swallow their food because their cuticle is a barrier

Question 6

What are some examples of nematode parasites?

Answer 6

• Intestinal roundworms
• Hookworm (burrow through feet)
• Filarial worms (elephantitis)
• Guinea worms (driven to extinction by humans)

Question 7

What is the life cycle of the Guinea worm?

Answer 7

1) Human drinks contaminated water w/ coepepods
2) Coepepods die and release guinea worm larvae
3) Fertilized female worm migrates to skin, causes blister, and discharges larvae
4) Larvae are ingested by coepepod

Question 8

How many germ layers do Nematodes have?

Answer 8

Triploblastic but pseudocoelomate

Question 9

What is the mode of locomotion for Nematodes?

Answer 9

Longitudinal muscles work against pseudocoel to move in tight spaces, write when not in tight spaces

Question 10

What is the cuticle used for in the Phylum Arthropoda?

Answer 10

As an exoskeleton

Question 11

What is the Arthropod cuticle made of?

Answer 11

chitin and protein

Question 12

How does the Arthropod cuticle grow?

Answer 12

Ecdysis

Question 13

How are Arthropod jointed appendages attached?

Answer 13

With muscles attaching from inside to exoskeleton

Question 14

How do terrestrial Arthropods breathe?

Answer 14

Respiratory system of internal tracheids with openings called spiracles
-this restricts size of arthropods

Question 15

What are the three layers of the Arthropod cuticle made of?

Answer 15

Mostly chitin and protein

Question 16

How is the growth of Arthropods characterized?

Answer 16

Growth is discrete (not continuous) step function

Question 17

How is ecdysis controlled in Arthropods?

Answer 17

Hormonal control

Question 18

Explain the Ecdysis process in Arthropods.

Answer 18

Basement membrane secretes new cuticle from inside out

• Epidermis eats old exoskeleton
• Rest of Exoskeleton separates

Question 19

How do Arthropods move their limbs?

Answer 19

from the inside-out with muscles acting on the exoskeleton

Question 20

What are apodemes?

Answer 20

Where the muscles attach to inside arthropods

-allow the flexion of articulated jointed appendages

Question 21

What kind of body plan do arthropods have?

Answer 21

Metameric body plan of repeated segments

• each segment has repeated ganglia to control motion of paired appendages
• Most species have segments combined to form tagmata

Question 22

What kind of nervous system do arthropods have?

Answer 22

Mostly ventral nervous system

Question 23

How do arthropods digest their food?

Answer 23

Only midgut is absorptive - exoskeleton covers most of gut

Question 24

What kind of circulatory system do arthropods have?

Answer 24

Open circulatory system - hemocoel is present

Question 25

Where did insects evolve from?

Answer 25

Crustaceans

Question 26

What features do Sub-Phylum Chelicerata lack?

Answer 26

No Mandibles, antennae, or appendages for sperm delivery

Question 27

What six pairs of appendages do Chelicerata have?

Answer 27

Chelicerae
Pedipalps
4 Walking Legs

Question 28

How does sub-phylum Chelicerata respire?

Answer 28

Book gills or Book lungs

Question 29

What are the two marine taxa of sub-phylum Chelicerata?

Answer 29

Class Merostomata and Class Pycnogonida (sea spider)

Question 30

What terrestrial species are part of sub-phyhlum chelicerata?

Answer 30

Spiders, scorpions, ticks, mites

Question 31

What are the features of sub phylum chelicerata, class arachnida?

Answer 31

• Chelicerae are fangs
• Pedipalps for prey capture
• Extracorpeal digestions
• Complex courtship b/c they lack appendage

Question 32

What tagmata are present in sub phylum chelicerata?

Answer 32

Cephalothorax and abdomen with chelicerae and pedipalps

Question 33

What tagmata do Sub phylum Myriapoda have?

Answer 33

None, only head + segments

Question 34

What are the two classes of sub phylum myriapoda?

Answer 34

Diplopoda (Millipedes) and Chilopoda (Centipedes)

Question 35

What are the characteristics of sub phylum myriapoda class diplopoda?

Answer 35

Herbivores and Fungivores

-2 pairs of legs per segment

Question 36

What are the characteristics of sub phylum myriapoda class chilopoda?

Answer 36

Carnivores with poison fangs

-1 pair of legs per segment

Question 37

How many tagmata do Sub phylum Crustacea have?

Answer 37

2 tagmata

-Cephalothorax and abdomen

Question 38

What are Biramous appendages found on sub phylum crustacea?

Answer 38

Modified appendages for many functions

-defense, feeding, walking, swimming

Question 39

Do Crustaceans have mandibles?

Answer 39

yes

Question 40

Where are the antennae located on crustaceans?

Answer 40

On the first segment

Question 41

What is the earliest stage of crustacean reproduction

Answer 41

Nauplius larvae which turn into adult