Animal biodiversity 3 - invertebrates

Question 1

what are the 3 defining features of the phylum mollusca?

Answer 1

1) muscular foot for locomotion
2) visceral mass containing internal organs
3) mantle - fold of tissue covering the visceral mass

Question 2

what are the 3 classes within the phylum mollusca?

Answer 2

1) gastropoda
2) bivalvia
3) cephalopoda

Question 3

what does gastropoda include?

Answer 3

snails. limpets, slugs

Question 4

what does the mantle cavity serve as in terrestrial snails?

Answer 4

lungs allowing them to breathe

Question 5

how do gastropoda move?

Answer 5

rippling motion of foot or by cilia

Question 6

what is the radula used for?

Answer 6

to graze on algae or bore holes in shells of prey

Question 7

what is torsion?

Answer 7

during development the visceral mass rotates 180 degrees moving male cavity(anus) over head

Question 8

how does the process of torsion take place and why might it be useful?

Answer 8

• retractor muscles on right side grow earlier than on left hand side so it moves -possible balance aid or safety from predators

Question 9

what are in the group bivalvia?

Answer 9

clams and oysters

Question 10

describe the shell of bivalvia?

Answer 10

divided into 2 halves - hinged at mid dorsal line

Question 11

where are the body and foot located in bivalvia and what is the foots use?

Answer 11

flattened inside the shell - foot used for digging or anchoring

Question 12

how do bilvalvvia feed?

Answer 12

they have gills adapted for filter feeding and gas exchange

Question 13

why are the head and radula (teeth) lost in bilvalvia?

Answer 13

because they have a sedentary lifestyle

Question 14

what are in the group cephalopods?

Answer 14

sqiuds and octopus

Question 15

in cephalopods what is the foot like?

Answer 15

modified into a siphon for propulsion or tentacles for feeding

Question 16

what is the cephalopods circulatory system?

Answer 16

3 hearts with blood blood due to high levels of copper

Question 17

3 features of cephalopods

Answer 17

1) complicated eye design with no blind spot
2) chromotophores which change colour for camouflage
3) well developed CNS and brain

Question 18

which of the 3 groups is most successful in terms of species diversity

Answer 18

gastropods

Question 19

what is the main feature of ecdysozoas giving them their name?

Answer 19

ecdysis- the shedding of their exoskeletons allowing them to grow in size

Question 20

what are the 2 groups of ecdysozoas?

Answer 20

1) Nematoda - round worms

2) Anthropoda - lobsters, spiders, insects

Question 21

what is a pseudocoel?

Answer 21

body cavity which is not the production of gastrulation

Question 22

what is the job of the pseudocoel and cuticle in nematoda?

Answer 22

act as hydrostatic skeleton

Question 23

what is nematoda reproductive strategy?

Answer 23

sexual reproduction with internal fertilisation

Question 24

what are 3 features of anthropoda body structure?

Answer 24

1) hard jointed exoskeleton or cuticle made of chitin an protein
2) segments fused in groups forming regions called tagma
3) appendages for specialised functions allowing efficient body plans

Question 25

3 features of anthropoda internal system?

Answer 25

1) open circulatory system - organs bathed in fluid
2) 3 guts
3) dorsal heart

Question 26

what are the 4 potential origins of insect wings?

Answer 26

• heat absorption in terrestrial ancestor
• gliding from vegetation to ground
• gills in aquatic ancestor
• swimming fins in aquatic ancestor

Question 27

what are the 5 anthropod sub groups?

Answer 27

1) trilobites (extinct)
2) Chelicerates ( spiders, ticks, horseshoe crabs)
3) crustacea ( lobsters and crabs)
4) Uniramia hexapods (insects )
5) chilopoda/diplopoda (millipedes and centipedes)

Question 28

what is a cephalothorax?

Answer 28

fused head and thorax

Question 29

what is the difference between the 4 of the anthropoid sub groups body sections?

Answer 29

trilobites - loads of segments not grouped together
Chelicerates - cephalothorax and abdomen
crustacea - head, thorax, segmented abdomen (3 mouth part appendages)
chilopoda/diplopoda - loads of little segments - paired segments are fused
hexapoda -3 sections: head thorax and abdomen

Question 30

how do insects carry out gas exchange?

Answer 30

well developed traheal system in which tubes lead to every cell in the body, spiracles regulate air flow and water loss

Question 31

how do cephalopods hunt?

Answer 31

they are active predators which use their tentacles to grasp prey and their beak like jaws inject an immobilising poison

Question 32

what is the difference between nematoda and annelids?

Answer 32

nematodes do not have a segmented body

Question 33

3 features of nematodes?

Answer 33

1) coelom not fully bound by mesoderm
2) cuticle shed during growth
3) lacks circulatory system nutrients transported via fluid in pseudocoel

Question 34

what was the result of the evolutionary changes of arthropods?

Answer 34

great diversification and efficient body plan that permits the division of labour among different regions

Question 35

3 important features of class insecta

Answer 35

1) sophisticated sensory organs including complex eye
2) well developed nervous system, allows complex behaviour
3) one or two pairs of wings derived from cuticle out-folding

Question 36

which arthropod group has the most sub species?

Answer 36

hexapoda