Week 7: Lecture 8: Arthropods 1

Question 1

Arthro

Answer 1

joint

Question 2

Poda

Answer 2

feet

Question 3

Arthropoda

Answer 3

most diverse of all the animal groups

Question 4

Environment of arthropods

Answer 4

mainly terrestrial

Question 5

Symmetry of arthropods

Answer 5

bilateral symmetry

Question 6

Body cavities of arthropods

Answer 6

coelomates

Question 7

Do arthropods have an exoskeleton?

Answer 7

yes

Question 8

Segementation in arthropods?

Answer 8

yes, segmented body, paired jointed appendages

Question 9

Respiratory, excretory, blood and sensorial systems in arthropods

Answer 9

well developed

Question 10

Reproduction in arthropods

Answer 10

sexual, with separate sexes

Question 11

What is the exoskeleton made of in arthropods

Answer 11

chitin and proteins

Question 12

Is the exoskeleton hard in arthropods?

Answer 12

yes

Question 13

What segregates the exoskeleton in arthropods?

Answer 13

the epidermis

Question 14

Chaetae

Answer 14

Bristle which aid movement

Question 15

Advantages of the exoskeleton in arthropods

4

Answer 15

1. independent from the environment
2. protection
3. reduce water loss (can live in drier environments)
4. more efficient locomotion

Question 16

Disadvantages of the exoskeleton in arthropods?

3

Answer 16

1. limits growth (needs to be shed)
2. limits gas exchange (need for respiratory organs)
3. limits movement

Question 17

What happens when an arthropod has grown to the extent of the exoskeleton

Answer 17

it must moult it

Question 18

Four stages of moulting the exoskeleton

Answer 18

1. intermoult
2. premoult
3. moult
4. postmoult

Question 19

Intermoult

stage 1 of moulting the exoskeleton

Answer 19

endocuticle unattaches from the epidermis

Question 20

Premoult

stage 2 of moulting the exoskeleton

Answer 20

all parts of the exoskeleton are reabsorbed

Question 21

Moult

stage 3 of moulting the exoskeleton

Answer 21

new exoskeleton produced,

the old epicuticle and exocuticle are disgarded

Question 22

Postmoult

stage 4 in moulting of exoskeleton

Answer 22

the new exoskeleton streches as the animal grows

Question 23

Gas exchange in aquatic arthropods

Answer 23

gills, extract oxygen from water

Question 24

Gas exchange in terrestrial arthropods

Answer 24

1. book lungs in scorpians and spiders

2. trachea in insects and millipedes

Question 25

Gas exchange in small arthropods

Answer 25

through the skin

Question 26

Three types of sensorial organs (receptors) in arthropods

Answer 26

mechanoreceptors
chemoreceptors
photoreceptors

Question 27

Mechanoreceptors

Answer 27

detect touch and vibrations

Question 28

Chemoreceptors

Answer 28

detect smell and taste

Question 29

Photoreceptors

Answer 29

ocelli and compound eyes

Question 30

Ocelli eyes

Answer 30

simple eyes

Question 31

Fertilisation in arthropods

Answer 31

mainly internal

Question 32

Pre-adaption

Answer 32

character present becomes useful

Question 33

Adaptations to life on land

6

Answer 33

1. exoskeleton and jointed appendages are pre-adaptive
2. reduced water loss by evaporation
3. reduced activity under dry conditions
4. gills replaced by tracheae or book lungs
5. excretion of nitrogen as uric acid or guanine, instead of ammonia
6. internal fertilisation and caring for young are pre-adaptive