the big 8 phyla

Question 1

classes of porifera

Answer 1

calcarea: calcarous sponges. skeleton of monaxouid,triaxonida or tetracoid spicules. not dividible into megascleres and microscleres
hexatinellida: six rayed silceous spicules (also tetrazonid forms). megascleres + microscleres
demospongiae: differentiated tetranoxined spicules and/or spongin fibres

Question 2

classes of cnidaria

Question 3

class of cnidaria

Answer 3

hydrozoa: usually colonial, sustrate attached, polyp has gastrovascular cavity w/o mesenteries. medusa has velum
scyphozoa: dominant medusa, larval metamorphosis, medusa by asexual budding. quadridiate symmetry by mesenteries. no velum.
cubozoa: medusa dominant, velum like structure, bell (4 flattened sides + simple margin). each polyp produces medusa by metamorphosis
anthrozoa: no medusa, biradial summetry. enteron divided by mesentries (>4)

Question 4

the 8 phyla

Answer 4

porifera
cnidaria
mollusca
platyhelminthes
annelida
nematoda
arthropoda
echinodermata

Question 5

hydriod reproduction

obelia

Answer 5

colonial marine hybrid
unisexual
external fertilisation in sea
single fertilised egg develops into a polyp
asexual reproduction to produce a colony

gastrozooids: feeding polyps with tentacles at tip
gonozooids: reproductive polyps proximal to gastro zooids

Question 6

scyphozoan reproduction

aurelia aurita

Answer 6

polyp fro mscyphinstoma develops from the planula larva, then metamorphosis into the strobilla and ephyra
like polyp pumps

Question 7

cuboza life cycle

Answer 7

each polyp produces a single medusa by complete metamorphosis

Question 8

classes of mollusca

Answer 8

polyplacophorans
cephlapods
gastropods
bivalves

Question 9

bivalves

Answer 9

• gill lamellae for respiration + feeding
• vs attached
• vestigeal head lacking eyes, tentacles nad radula
• mantle fused to become inhalant and exhalant siphon
• ctenidia used for feeding + gas exchange
• hinge ligaement joins shells
• ## periastracum: outer horny layer protecting CaCO3

Question 10

polyplacophorans

Answer 10

• chitons
• dorsal shell of 8 articulated plates
• lack eyes +tentacles
• slow movement
• rolls into ball as defence

Question 11

gastropods

Answer 11

• snails, slugs, limpets, whelks, nudibranchs
• univalve either coiled or uncoiled
• torsion
• body may be secondariy detorted
• reduced or absent shell

Question 12

cephlapods

Answer 12

• squid, octopus, cuttlefish, nautlis
• marine predators
• molluscan foot modified into tentacles/arms or siphon for propulsion and respiration
• complex nervous system and eyes
• chromatophores in skin for communciation and crypsis

Question 13

classes of platyhelminthes

Answer 13

tuberllaria
trematoda
monogenea
cestoda

Question 14

tuberllaria

Answer 14

-mostly free living
ocelli
mouth in centre with pharynx on either side
unsegemented

Question 15

trematoda

Answer 15

-tapeworm
no digestive system–> nutrients abosrbed through body wall
attach via scolex
complex life cycles

Question 16

monogenea

Answer 16

• flukes with a single host
• poterior hook for attachment (ospisthaptor)
• mouth at one end rather than in the centre

Question 17

cestoda

Answer 17

• flukes w/2 or more hosts
• two simple suckers, one atnerior and one central (distinguishing)
• not truly segmented

Question 18

classes of annelida

Answer 18

polycheata and clitellata

Question 19

polycheata

Answer 19

• well defined head (nuchal organ, filter feeders of pharynx everted to catch prey)
• parapodia (paried) with chaetae

Question 20

clitellata

Answer 20

clitellum: thickening of epidermis at genital pores that secretes egg cocoon, circular and longitudinal muscle, coalemic fluid functions as hydrostatic skeleton
earthwroms: hermaphordites, egg cocoon from clitellum
leeches: anterior and posterior luckers, lack coelomic compartment

Question 21

nematoda

Answer 21

• round worms
• pseudocolom
• ecydycozoa
• lack circular muscles –> undulating locomotion
• roundworms, hookworms, heart worms
• complete digestive system
• ganglia and nerve cells

Question 22

arthropod subphyla

Answer 22

crustacea
hexapods
chelicerata
myrapods

Question 23

crustacean classes

Answer 23

branchipoda
maxillapoda
malacotraca

Question 24

hexapod classes

Answer 24

entognatha
insecta

Question 25

chelicerata classes

Answer 25

Arachnida
Pycnogonida

Question 26

myriapod classes

Answer 26

chilopoda –> centipedes (poison claws)
diplopoda –> millipedes

Question 27

echinodermata

Answer 27

helethuroidea: sea cucumbers
crinoidea: sea lillies
asteroidea: star fish
ophiurodea: britlle stars
echinidae: sea urchins