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Flashcards in Lecture 5 RH Deck (94)
1

What is so special about arthropods?

First animals to colonize land

They are the most diverse animal phylum (900000 species)

2

What are the key features of arthropods?

triploblastic

bilateral symmetry

Ecdysozoan protostomes

Coelomate

Chitinous exoskeleton

Metameric, heteronomous, tagmatisation

Paired, jointed appendages

Most are highly cephalised

Most reproduce by internal fertilization

3

What are ecdysozoan protostomes?

Protostomes that molt and dont undergo spiral cleavage

4

What is heteronomous segmentation?

Segments are different

5

What is homonomous segmentation?

All segments are the same

6

What is tagmatisation?

Multiple segments fused into distinct body regions.

7

Why is tagmatisation significant?

Allows specialization of segments for different purposes

8

What is the exoskeleton of arthropods made of?

chitin in some species of crustaceons it is reinforced with calcium or wax layer

9

What is the function of the arthropod exoskeleton?

Protection against predators and dessication

Structural support

10

Where do legs arise from in arthropods?

Paired jointed appendages are modified as legs

11

How is the exoskeleton's rigidity overcome in arthropods when growing?

Molting

12

What kind of muscles do arthropod limbs have?

Antagonistic muscles

13

What is the problem with molting?

Molting is an energy and time consuming process which can get an arthropod killed

14

What are tracheae?

Hollow internal tubes and invaginations of cuticle

15

What is the function of tracheae?

Deliver oxygen to tissues

16

How is water loss reduced in arthropods?

Spiracles are closed by valves in some species to reduce water loss

17

What are wings made from?

Evaginations of cuticle

18

What are some features of the head of highly cephalised arthropods?

Well-developed central ganglia

Image-forming eyes (Compound eyes with units called ommatidia)

Antennae and antennules form mecahanosensory organs and chemosensory organs

Vibration sensors

19

What are the subphyla of arthropods?

Trilobita (extinct)

Crustacea: crabs, lobsters, shrimp, barnacles

Chelicerata: Horseshoe crabs, spiders, scorpions, ticks, mites

Myriapoda: centipedes, millipedes, pauropods, symphylans

Hexapoda: insects, collembolans, proturans

20

What are the anatomical features of trilobites?

Biramous appendages, 1 pair of antennae

21

What are the anatomical features of crustaceons?

Biramous appendages, 2 pairs of antennae, naupilius larvae

22

What are the anatomical features of chelicerata?

uniramous appendages and no antennae

23

What are the anatomical features of myriapodae?

uniramous appendages 1 pair of antennae

24

What are the anatomical features of Hexapodae?

Uniramous appendages, 1 pair of antennae, no abdominal appendages

25

Which group of arthropods is most diverse?

Insects followed by chelicerates

26

What are the features of subphylum crustacea?

45000 described species

Great diversity in body forms and ecological niches

Mostly aquatic, some terrestrial

Display all types of feeding modes (predator, scavenger, herbivore, suspension feeder, deposit feeder) life styles

An important food group for humans

27

What are the traits of a generalized crustacean?

3 tagmata, or can have fused cephalothorax

Carpace variable

Head appendages

28

What are the typical crustacean head appendages?

antennules

Antennae

Mandibles

1st Maxillae

2nd Maxillae

29

What are the typical thorax appendages in crustaceanss?

up to 3 pairs of maxillipedes

Often 5 pairs of pereopods

30

What are the typical abdominal appendages?

6 pairs of pleopods

Telson and uropods

31

What are pereopods functional for?

Walking legs

32

What are maxillipeds?

Important limbs for manipulating food

33

What are pleopods functional for?

Swimming legs

34

Where do claws arise from?

pereopods

35

What are telson and uropods required for?

swimming

36

What are the appendage rami of crustaceans?

Exopod

Endopod

37

Where are the gills typically located on sea dwelling crustaceans?

exopod

38

What is autonomising the leg?

Dropping the leg off in reaction to predator grasping it

39

What body systems does a crustacean have?

Complete digestive tract with gastric mill (teeth like structures at the opening of the stomach)

Open circulatory system: hemocoels (reduced coelom), heart ostia

Excretory system (metanephridia in head aka green glands)

Nervous system with brain and segmental ganglia

*muscles and exoskeleton inside the stomach to assist digestion

40

Where is the anus located in crustaceans?

The very posterior end

41

What is a hemocoel?

remnant of coelom which has blood accumulating forming sinuses

42

Where are gills located in crustaceans?

on legs outside of the body

43

How do crustaceans sense balance?

Statocysts on uropods

44

Do crustaceans have compound eyes?

Yes

45

How do crustaceans reproduce?

Internal fertilization (often with gonopod but highly variable)

Fertilized eggs are often brooded by females

46

Are crustaceans mono or dio ecious?

Dioecious

47

What larva do crustaceans produce?

nauplius (free swimming or in egg)

then the following can be the next stages:

Copepodite (copepods)

Cyprid (barnacles)

Zoea (crabs and other decapods)

Megalopa (crabs and other decapods)

48

What is the life cycle of a prawn?

1) Fertilized eggs are released offshore

2) Nauplius stage followed by protozoea and mysis

3) Juveniles return to inshore nursery areas

4) Adults then go offshore to lay their eggs

49

What are the classes of crustaceans?

Class malacostraca (includes decapoda, euphausiacea, stomatopoda, amphipoda, and isopoda)

Class Branchiopoda (contains fairy shrimp, water fleas, tadpole, and clam shrimp)

Class Maxillopoda (Contains Barnacles, tongue worms, ostracods, seed shrimp)

50

What are the features of decapods?

2 tagmata (cephalothorax + abdomen)

3 maxillipeds

5 Pereopods (first 3 can chelate)

Pleopods are variable

Serial homology: Body segments are homologous

Occupy all habitats and feeding modes (deposit feeder, suspension feeder, predator, herbivore, scavenger)

51

What are the sexual dimorphisms in crabs?

Males have a narrow abdomen and pleopods modified as gonopods

Females have a wide abdomen and pleopods used to carry fertilized eggs

52

What are the features of subclass cirripedia (barnacles)?

All marine and sessile

Free-living species are filter feeders

Calcareous plates

"Mantle cavity"

6 pairs of thoracic cirri.

Reduced body (uncephalised and no abdomen)

53

What is the life cycle of barnacles like?

1) Sexual reproduction results in nauplius larva which becomes a cyprid larva and loses antennae.

2) Cyprid larvae finds a rock and attaches to surface

3) Cyprid larva metamorphoses and produces a shell around it

54

Are barnacles hermaphrodites?

Yes

55

Are barnacles mono or dio ecious?

Monoecious

56

What do barnacles do to mate considering that they are sessile?

They have an extensible penis which can grow to reach the female.

57

What are the features of parasitic crustaceans?

Most show greatly reduced body form

They parasitise a wide range of animals including other crustaceans

All have typical crustacean larva

58

What is a defining feature of crustaceans?

The nauplius larval stage

59

How do the limbs adapt to the different environments crustaceans live in?

Different crustaceans use different specialized limbs to swim around

60

What are crustacean adaptations to allow walking?

Pereopods with varying degrees of specialization

61

What are crustacean adaptations to allow burrowing?

Amphipod can create a specialized limb out of their amphipod or their uropod in order to burrow

62

How do suspension feeders modify their limbs for feeding?

In copepods: Maxilliped and 2nd maxilla are specialized for feeding.

In Decapods: 2nd antennae

Euphasids and branchiopods use pereopods

63

How are limbs adapted to swimming?

In fairy shrimp and euphasid: Pereopods or pleopods move in waves of power and recovery strokes

In decapods: 5th pereopods form swimming legs and in some cases uropods form flippers

Copepods flick antennae

64

What is modified for scavengind and deposit feeding?

Pereopods in some decapods

2nd antennae in gnathopods

Specialized stabbing pereopods in some

65

What are the characteristics of the phylum hexapoda?

uniramus appendages

1 pair of antennae

3 tagmata

3 pairs of legs on thorax

Various head appendages

abdominal appendages are mostly absent

Waxy cuticle

Tracheae for gas exchange

malpighian tubules for excretion

Wings

66

How do insects excrete their wastes?

Malpighian tubes

67

What are chelipods?

Crab claws which are modified pereopods

68

What are the main physiological adaptations to life on land in insects?

Malphigian tubes with efficient resorption of water

Tracheae which deliver oxygen directly to muscles

Valves in tracheae which close to reduce water loss.

69

What are chewing mouthparts?

Strong mandibles with toothed plates

Maxillae to manipulate food

70

What are chewing mouthparts needed for?

Predation, herbivory, or scavenging

71

Which insects typically have chewing mouthparts?

Grasshopper

Dragonfly

Beetle

Cockroach

Termite

Biting Flies

72

How do piercing and sucking mouthparts work?

Needle-like labium or stylet modified from maxillae and mandibles.

Tubular labrum for sucking while saliva flows out through hypopharynx

Used to pierce flesh or plant cells

73

Which animals typically have piercing and sucking mouthparts?

Moquitos

Cicadas

Aphids

Lice

Some flies

74

How do sucking mouthparts work?

Feed on energy rich liquids (eg nectar)

They are long and just suck

75

Which insects have sucking mouthparts?

Butterflies and moths have no mandibles

Honey bees use labial palps and maxillae

76

How do lapping mouthparts work?

Labium is modified into absorptive pads

Used for scavenging on any liquids

Biting flies use mandibles to cut flesh and make it bleed before lapping it up.

77

What are some leg modifications in insects?

Hair on bee legs collect pollen

Mole cricket can dig with legs

Grasshopper has strong legs for jumping very high

78

What are some antennae modifications in insects?

Some are modified for sensing chemicals, vibrations, air currents, surfaces

79

What are some wing modifications in insects?

Most insects have 2 pairs of wings

Beetle have wing covered by a pair of elytra

Flies have wings and halteres

80

What are the features of wings of insects?

They are formed by the evagination of cuticle with top and bottom membrane

Veins move to alter shape of wing

Wings pivot on side plate of exoskeleton

Compression of thorax causes wings to flap

Elasticity of exoskeleton can be used to increase beat frequency.

81

What is a hemimetabolous life cycle?

Gradual change between instars

82

What is holometabolism?

Complete metamorphism

83

Why is it advantagous for separate stages of a lifecycle in insects?

Each stage of the life cycle specializes for a certain function.

84

At what taxonomic level are insects separated?

Order

85

Which orders are most commonly used by biologists?

Blattaria (cockroaches)

Coleoptera (beetles, fireflies, weevils)

Diptera (flies, mosquitos)

Hymenoptera (ants, bees, wasps)

Lepidoptera (Butterflies, moths)

Odonata (dragonflies)

86

What is happening to pollinating insect populations?

They have been declining in numbers causing a decline in number of plants that depend on these insects

87

What is causing colony collapse disorder?

Common pesticides are causing brain damage to bees and this disrupts their function.

88

What are the features of myriapods?

Uniramous appendages

1 pair of antennae

2 tagmata

Waxy cuticle

Tracheae, spiracles cannot be closed

Malpighian tubules

89

What do malpighian tubules do?

Help them produce highly concentrated excretions

90

What are the features of chilopoda (centipedes)?

1 pair of legs per segment

Last pair of legs is sensory or defensive

Repugnatorial glands

Maxilliped on 1st trunk segment has forciple

91

What is a maxilliped?

Maxillae like legs for manipulating food

92

What is a forcipule?

Stabbing legs

93

What are repugnatorial glands?

Defensive glands that secrete a chemical that is caustic

94

What are the features of diplopoda (millipedes)?

Diplosegments (fused segments)

1st trunk segment without legs

2nd - 4th segments with 1 par of legs each

Remaining segments with 2 pairs of legs each

Repugnatorial glands

Harder cuticle than that in centipeds