Chapter 11 - Molluscan Success

Let me know if I am missing something that you'd like on here or if you disagree with one of my definitions since they were self found

gastropoda

stomach-foot

snails, slugs, limpets, nudibranchs

bivalvia

two shells

clams, oysters, mussels, and scallops

cephalopoda

head foot

squids, octopuses, cuttlefish, and chambered nautiluses

stomach

holds food before it passes to the cecum (SQUID)

beak

hard, sharp jaws that shred and tear food (SQUID)

tentacle

pair of appendages longer than the arms; used to capture prey and bring it closer to its arms and mouth (SQUID)

arm

one of eight similar appendages that hold/manipulate prey while its being eaten (SQUID)

buccal bulb

muscular structure in the mouth opening; house the beak and radius; food passes through it to esophagus (SQUID)

esophagus

food tube (SQUID)

superior mandibular muscle

largest muscle to operate beak (SQUID)

testis

male gonads (SQUID)

ovaries

female gonads

chromatophores

pigmented spots that change color in response to stimuli (SQUID)

siphon

pushes water in and out of the mantle, propels squid (SQUID)

mantle

muscular tube that surrounds organs (SQUID)

gills

feathered, highly vascularized organs for gas exchange (SQUID)

branchial hearts

pair of hearts that pumps deoxygenated blood from the body to the gills (SQUID)

systemic heart

central heart that pumps blood to the body (SQUID)

intestine

end of digestive system that empties into anus (SQUID)

collar/fin

edge of mantle around squids ventral end (SQUID)

caecum

small sac that connects to stomach; absorbs nutrients (SQUID)

ink sac

silvery organ responsible for releasing ink (SQUID)

penis

male organ for transmission (SQUID)

kidney

waste is transferred from blood (SQUID)

funnel retractor muscle

helps to support/position funnel during jet locomotion (SQUID)

excurrent siphon

a tube through which water/waste exits the mantle cavity of a bivalve (CLAM)

mantle

area that holds air, water, and organs (CLAMS)

heart

circulation of blood throughout the body of the clam (CLAM)

palp

used to guide food towards/into the mouth (CLAM)

incurrent siphon

a tube through which water/food enters the mantle cavity (CLAM)

anterior retractor muscle

pulls the foot back into the shell/opens shell (CLAM) front

gills

filters water in order to produce oxygen so the clam can live (CLAM)

gonad

releases sperm/egg into the water, and produces gametes (CLAM)

mouth

where food goes in in order to be properly digested (CLAM)

coelom

body cavity (CLAM)

posterior adductor muscle

muscle that aids in closing the shell (CLAM) back

valve

a hard protective layer that protects against predators (CLAM)

anterior adductor muscle

muscle that aids in closing the shell (CLAM)

pearly layer

the shiny layer/inner-most (CLAM)

hinge

joins the two halves together (CLAM)

foot

used for moving and attaching itself to areas - giant muscle (CLAM)

umbo

large muscle that holds together the two shells of a clam - oldest part (CLAM)

horny layer

outside layer of a clam - hard - camouflage (CLAM)

gut

transports waste, completes digestion, absorbs nutrients, forms feces (CLAM)

posterior retractor muscle

pull the foot back into the shell - opens shell (CLAM) back

digestive gland

used for digestion after passing the mouth - like a liver - secretes mucus and enzymes to break down food (CLAM)

polyplacophora

many plated

chiton

scaphopoda

shovel foot

tooth shells/tusk shells

monoplacophora

one plated

deep sea limpets

solenogastres

marine like subrates

lack shell

crawl on ventral foot

minute calcareous spicules

carnivores

caudofoveata

deep sea

worm like

feed on foraminifera

lack shell, foot, and nephridia

120 species

evolutionary perspective of molluscs

• triploblastic (endo, meso, ecto)

• coelomate (body cavity)

• very successful

• relationships with other animals

  • lophotrochozoa (lophophore/feeding tube or trochophore/larval stage)

true

T OR F

the body of a mollusc has two parts: a head-foot and visceral mass

true

T OR F

the mollusc’s mantle secretes a calcareous shell, and covers the visceral mass

false - does

T OR F

the mantle cavity does not aid in excretion, gas exchange, elimination of digestive wastes, and release of reproductive products

false - bilateral

T OR F

a mollusc has radial symmetry

true

T OR F

a mollusc has trochophore larvae, spiral cleavage, and schizocoelom formation

false - decreased

T OR F

a mollusc is coelom increased

true

T OR F

molluscs have an open circulatory system (minus cephalopods)

true

T OR F

molluscs have a special feeding tube called a radula

false - some are separate sexes and some are hermaphrodites

T OR F

all molluscs are hermaphrodites

head foot

• elongate

• mouth

• foot for attachment and locomotion

visceral mass

• dorsal to head foot

• organs of digestion, circulation, reproduction, excretion

mantle

• enfolds body

• secretes shell

mantle cavity

gas exchange, excretion, elimination of digestive wastes and reproductive products

radula

• supported by odontophore

• rasping food

35,000 species

how many species are there of gastropods?

torsion

causes the animals anus and mantle to end up above its head

shell coiling of gastropods

• earliest fossils, one plane

• modern, asymmetrical

  • more compact

  • internal organs asymmetrical and sometimes no longer paired

locomotion of gastropods

• flattened foot

• cilia propel over mucous trail

  • muscular waves (peristalsis)

feeding/digestion of gastropods

• most scrape algae and attached organisms

• herbivores, predators, scavengers

• digestive tract

  • ciliated

  • food incorporated into mucous mass called protostyle

gas exchange of gastropods

• one or two gills in mantle cavity

• land snails (pulmonates)

open circulatory system of gastropods

• blood bathes in tissues and sinuses

• heart - single ventricle and single auricle

• functions

  • transports nutrients, wastes, and gases

  • hydraulic skelton

nervous system of gastropods

six ganglia plus nerve cords

sensory structures of gastropods

• eyes at base of ends of tentacles

• statocysts in foot

  • osphradia in mantle cavity

excretion of gastropods

• single nephridium

  • result of shell coiling

• discharges into mantle cavity or adjacent to mantle cavity (pulmonates)

• ammonia (aquatic species)

• uric acid (pulmonates)

dioecious reproduction for gastropods

external fertilization

eggs shed singly or in masses

some dioecious marine species

monoecious reproduction for gastropods

copulation for internal fertilization

sperm transfer may be mutal or one way

eggs shed in strings/masses

bivalves

what class are filter feeders

by capturing their food with their tentacles and arms

how to cephalopods feed

true

T OR F

the class of polyplacophora feed on attached algae

a muscular foot, visceral mass, and mantle

what three body parts do all molluscs have in common?

siphon

squids use their ________ to fire a jet of water which allows them to swim very quickly

closed

sense

complex

cephalopods have a ______ circulatory system, well-developed ______ organs, and a _______ brain.

mucus trail

defense mechanism of gastropods

inking

defense mechanism of cephalopods

hard outer shell

defense mechanism of bivalves

digestion of gastropods

crystalline style and gastric shield

evolved in response to predatory lifestyles

how did molluscs evolve?

they are not similar

how to molluscs compare to other invertebrates/vertebrates