Arthropods

Question 1

What subphyla exist in the arthropoda?

How are they organised?

Answer 1

• Chelicerata (A)
• Myriapods (B)
• Crustacea (paraphyletic) (C)
• Hexapods (D)
• Trilobites (extinct) (E)

(E, A,(B,C,(A)))

(B,C,(A)) = Madibulata

Question 2

Describe the generalised structure of arthropod?

Answer 2

• segmented
• joint appendages
• exoskeleton cuticle
• circulatory system
• ventral nerve cord
• musculature
• through gut

Question 3

What are the different cuticles called that make up the arthropod skeleton?

Answer 3

Ventral side: Sternite

Dorsal side: Tergite

Appendage interface: Plurite

Question 4

Describe the arthropod circulatory system.

Answer 4

Heart on dorsal side

Hemocele fills body cavity to help nutrient and gas exchange to all body parts

Question 5

Why do most arthropods have heterogeneous segmentation?

Answer 5

Segments have been:

• lost
• fused
• specialised

Question 6

What is tagmosis?

Answer 6

The grouping of segments with similar function /structure over evolutionary time

Tagmosis occurred independently between insects, crustacean and chelicerates

Question 7

What distinct body areas have been made due to tagmosis?

Answer 7

• Head region
• thorax
• abdomen

OR

• Cephalothroax
  (fused head and thorax)

Question 8

What appendage muscles do arthropods have?

Answer 8

• Flexor allow appendage to be bent
• Extensor muscle allow appendage to be extended
• Protractor muscles appendage to be pulled away from body
• Retractor muscles appendage to be pulled towards body

Question 9

What is ecdysis?

Answer 9

The process of moulting

Stages:
- Pre-moult
(new cuticle developes under dead-old cuticle)

• Moult
  (shedding of old cuticle)
• Post-moult
  (new moult gets harder through sclarotization)
• Inter-moult
  (periods between moulting)

Question 10

Describe the structure of Myriapods.

Answer 10

• head and trunk region
• single antennae
• open tracheae
  (thus limited to humid environments)

Question 11

Describe the general structure of Chaliserates.

Answer 11

• two tagmata
  cephalothorax and abdomen
• compound eyes

Question 12

What are the many uses of silk to spiders?

Answer 12

• reproduction
  (sperm web)
• feeding
• sensing
• locomotion
• dispersal
  (spiderlings produce silk from spinnerets and balloon around)

Question 13

What are the six major classes of crustacea?

Answer 13

• Maxillopoda (polypheytic)
  Tongue worm
  Fish lice
• Ostracoda
  Sea shrimp
• Branchiopoda
  Fairy shrimp
  Water fleas

- Malacostraca (and Maxillopoda)
Crabs
Krill
Woodlice
Barnicles
(the rest of the maxillopods)

• Remipedia
• Cephalocarida

Question 14

What is the general crustacea body plan?

Answer 14

• two paired antennae
• metamorphosis
  (with nauplius larvae)
• No general body plan
  (but at least two tagmata)

Question 15

What is the standard tagmosis of malacostraca?

Answer 15

• Head, thorax, abdomen

- Appendages on each

Question 16

What is the general hexapod body plan?

Answer 16

• 3 tagmata
  (head, thorax, abdomen)
• tracheal system
  (abdominal spiracles, waxy cuticles, hyperosmotic excreta)

Question 17

What are the two main classes of hexapod?

Answer 17

• Enthognatha

- Insecta (Ectognatha)

Question 18

What are the two Insecta subclasses?

Answer 18

• Apterygota (wingless)

- Pterygota (winged, 2 in adult)

Question 19

What are the four major superorders of the pteragota

Answer 19

• Paleoptera
  Mayflies
  Dragonflies
  Damselflies
• Polyneoptera
  Grasshopper
  Termites
  Mantises
• Paraneoptera
  True bugs
  Lice
• Holometabola
  Major four

Question 20

What is the mode of development in the holometabola?

Answer 20

holometabolous development

• Egg
• Larva
• Pupa
• Adult

Question 21

What are the major four

Answer 21

Lepidoptera
Hymenoptera
Coleoptera
Diptera

Question 22

What is hemimetablous development?

Answer 22

• Egg
• Nymph
• Adult

Question 23

What are the different specialised appendages of insect?

Answer 23

Curosial foreleg
(walking)

Saltartory hind leg
(jumping)

Fossorial forelegs
(digging)

Natatorial hing leg
(swimming/diving)

Raptorial foreleg
(catching)

Question 24

What are the different specialised mouth parts of insect?

Answer 24

Chewing

Lapping

Siphoning

Piercing

Question 25

What are the different specialised wings of insect?

Answer 25

Elytra
(beetles)

Hemielytra
(leathery, true bugs)

Membranous wings

Scaly wings

Fringed wings

Tegmina
(protection in grasshopper)

Holteers
(flies)

Communication
(stridulation)

Question 26

How is powered flight achieved?

Answer 26

Power stroke
(down and forwards)

Recovery stroke
(up and backwards)

Question 27

Describe the musculatrure involved in dragonfly powered flight.

Answer 27

Elevator muscles contract, depressor muscles relax → wing up

Elevator muscles relax, depressor muscles contract → wing down

Question 28

Describe the musculatrure involved in flies powered flight.

Answer 28

Indirect muscles that don’t attack to wing.

• Indirect Vertical flight muscles→Recovery stroke
  (They pull on the roof of the thorax → wings rise and thorax widens/lengthens.
  This stretches the longitudinal muscles)
• Indirect longitudinal flight muscles → power stroke
  (They pull the anterior and posterior ends of the thorax →wings lowers and thorax narrow/shortens)

(steering achieved by direct muscles)

Question 29

What is ametaboly?

Answer 29

No metamorphosis

Question 30

How do we define success as a species?

Answer 30

Evolutionary parameters

• Clade longevity
• Number of species
• Species distribution

Ecological parameters

• Ecological diversity
• Dominance
• Impact on ecosystems