Module 3

Question 1

Lophotrochozoa

Answer 1

Phylum Mollusca

Phylum Annelida

Question 2

Phylum Mollusca Characteristics

Answer 2

• Found in freshwater, saltwater, terrestrial
• found in temperate, tropical, subtropical
• Triploblasts
• Eucoelomates
• Bilateral symmetry

Question 3

Parts Of phylum Mollusca

Answer 3

The Mantle: dorsal layers of tissue, secretes shell

The mantle cavity: space between mantle and organs, gills located here

Ctenidia: Gills, water moves throughout them

Counter current exchange system: way of situating water and blood movement opposite each other

Visceral mass: internal tissues and organs

Radula: in most Mollusca, can have teeth associated with it

Foot: muscular, variety of purposes, pedal waves, locomotion, anchoring, feeding, digging

Question 4

The Mantle

Answer 4

The shell,

3 layers:
Periostracum ( thin outer layer)
Prismatic ( thick layer, organic but also has calcium carbonate
Nacreous layer

Univalves vs bivalves

Question 5

Subphylum Aculifera

     Class Aplacophora

Answer 5

Only live in the ocean, small, Vermaphorm, calcareous spicules, don’t have a foot, cilia, don’t have gills, hermaphroditic and gonochoristic
External fertilization, has mouth with radula

Question 6

Subphylum aculifera

Class polyplacophora

Answer 6

Chiton, only live in the ocean, flat bodies, 8 overlapping plates secreted by the mantle, giant foot to attach to substrate and move, herbivore, ctinedia, eye spots

Question 7

Subphylum Conchifera

Class Monoplacophora

Answer 7

• Univalved shell, only in the ocean, small, muscular foot, gonochoristic, radula

Question 8

Subphylum Conchifera

Class Scaphopoda

Answer 8

Tusk shell, univalves, marine, foot is used to dig into sediment, mantle tissue is ciliated, simple nervous system

Question 9

Subphylum Conchifera

Class Gastropoda

Answer 9

vary in size, enclosed in a univalves shell that is coiled clockwise, operculum, foot, carnivores, radials, tentacles, ctenidia,

Question 10

3 Groups in Class Gastropoda

Answer 10

Prosobranchs, Opisthobranchia, Pulmonates

Question 11

Prosobranchs

Answer 11

welks, conchs, cone snails, limpets

Gills in front of heart, anterior mantle cavity, proboscis ( mouth that is modified) , siphon (pulls in water) , internal fertilization, most basal group, heavy shell, foot is powerful, open circulatory system

Question 12

Opisthobranchia

Answer 12

sea hares, sea slugs, nudibranchs

gills in back of heart, tentacle, gill plume or create, often have a second pair of tentacles, don’t really have a shell, hermaphroditic, internal fertilization, oviparous, use nematocysts to defend itself

Question 13

Pulmonates

Answer 13

terrestrial gastropods, do not have gills, highly vascularized mantel cavity ( use it like a lung for gas exchange, pneumostome ), hermaphroditic with internal fertilization, oviparous, exchange sperm

Question 14

Subphylum Conchifera

Class Bivalvia

Answer 14

mostly saltwater but also terrestrial, range in size, likes shallow water, flattened body plan, head is highly reduced, has a foot, sessile, omnivores, variable nervous system, fertilization is external and gonochorisitic except for scallops

Question 15

3 Groups of Class Bivalvia

Answer 15

Prosobranchs, lamellibranchs, septibranchs

Question 16

Protobranchs

Answer 16

deep water clams, strictly in the ocean, substrate feeders (burrow deep in sediment), most basal group

Question 17

Lamellibranchs

Answer 17

scallops, mussels, oysters, clams

filter feeders, more surface area in ctenidia, byssal threads (bundle of threads of filaments from foot, helps anchor bivalves), have 2 siphons,

Question 18

Scallops (Lamellibranchs)

Answer 18

hermaphroditic, free living, have small holes that direct water through to direct movement, adapted to have eyes

Question 19

Septibranchs

Answer 19

only in the ocean, can create suction with their gills into mantle, more active approach to feeding, carnivores

Question 20

Subphylum Conchifera

Class Cephalopoda

Answer 20

Octopus, Squid, Cuttlefish

calcareous pen, foot is highly modified into tentacles, most derived group, closed circulatory system, complex nervous system, gonochorisitc with internal fertilization, chromatophores ( camouflage cells, Iridophores, color change voluntary and involuntary), Ink sacs (used to confuse predators, extension of the hindgut, mucus and melanin) Have chambered eyes ( cornea, sense, iris)

Question 21

Molluscs Overview

Answer 21

extracellular digestion (filter feeding or substrate feeders)

Respiration ( ctenidia, diffusion, pulmonates)

open circulatory system except for cephalopods

nervous system is variable

univalves or bivalves

Locomotion varies

Question 22

Phylum Brachiopoda

Answer 22

a lot of extinct species, out competed by bivalves, lamp shells, marine, solitary, triploblastic eucoelomates, bivalved

Question 23

Distinct parts of phylum Brachiopoda

Answer 23

lophophore ( ring of tentacles around the mouth)

Pedicle ( for water excretion)

Question 24

Phylum Brachiopoda

Class Articulata

Answer 24

shells hinged with interlocking teeth, shells composed of calcium carbonate

Question 25

Phylum Brachiopoda Class Inarticulata

Answer 25

2 hinged shells do not interlock, shell composed of calcium phosphate

Question 26

Phylum Annelida

Answer 26

range in size, humid habitats, free living, segmented, bilateral symmetry, thin outer epidermis, chitinous chaetae

Question 27

Phylum Annelida Class Clitellata

Answer 27

leeches, oligochaete worms most are terrestrial, motile, hermaphroditic, can perform asexual reproduction, direct development, clitellum participates in reproduction

Question 28

Phylum Annelida Class Polychaeta

Answer 28

mostly In saltwater, range from sessile to motile, live in tubes, parapodia with many chaetae, gonochoristic, indirect development

Question 29

Class Polychaeta 3 groups

Answer 29

Siboglinid, Echiurans, Sipunculans

Question 30

Siboglinid

Answer 30

tube worms, live in extreme environments, secrete their tubes, anterior cephalic lobe, long unsegmented trunk with organ, short segmented posterior region with lots of hooked setae

Question 31

Echiurans

Answer 31

large burrowing worms in the shallow oceans, anterior proboscis with cilia, unsegmented trunk with long coiled digestive tract, burrow, do not have a tube for support, not segmented

Question 32

Sipunculans

Answer 32

Anterior, retractable, introvert with mucus covered tentacles, unsegmented trunk with U shaped digestive system, small burrowing worms but sometimes occupy others tubes and shells, occur at a range of depths, tentacles

Question 33

Annelid Comparison

Answer 33

Clitellata vs Polychaeta Feeding: substrate filter and fluid , filter Respiration: Diffusion, gills and tentacles Circulation: closed, closed except for sipunculans Response to Stimula: a lot of mechanoreceptors, sensitive to touch and photoreceptors Support: hydrostatic skeleton or tubes, movement by peristalsis Reproduction: Direct, Indirect