Biology 11- Mollusks

response of Bivalvia

• no cephalization, simple nervous system

• simple sense organs (ocelli, statocysts, touch receptors)

Feeding of Bivalvia

• herbivores, carnivores, filter feeders

• food and water move through incurrent siphon and towards the gills and mouth

• plankton gets stuck in sticky mucus and cilia

respiration of Bivalvia

gills located inside mantle cavities

internal transport system of Bivalvia

• open circulatory system

• two “kidneys” lie below the heart or filter blood

• blood works way through tissues in open spaces (cavities)

movement in Bivalvia

• larvae are free swimming

  • adults are sessile

excretion in Bivalvia

• anus empties into the excurrent siphon (remove waste and H2O) 

• Solid waste passes through anus in feces 

• Ammonia is filtered from the blood by Nephridia 

reproduction in Bivalvia

• External fertilization 

• Eggs and sperm released in enormous numbers 

• Hermaphrodites pair and fertilize each other's eggs at the same time 

• **oysters can change sexes and produce eggs sometimes and sperm other times 

response of Cephalopoda

• No brain 

• consists of many fused ganglia. 

• Very intelligent and can remember information 

• Advanced eye  

• Can learn

feeding of Cephalopoda

Uses a powerful beak and radula to tear apart prey 

respiration of Cephalopoda

Gills located inside mantles cavities 

internal transport system of Cephalopoda

• Small internal shell or no shell at all 

• Squid's internal shell is a thin, flexible rod called a PEN 

• closed circulatory system

  • blood always found in vessels

movement in Cephalopoda

Most have 8 tentacles with suction cups to capture prey

excretion of Cephalopoda

• Solid waste passes through anus in feces 

• Ammonia is filtered from the blood by Nephridia 

Reproduction of Cephalopoda

• internal fertilization in the female

Feeding of Gastropod

• uses radula to feed

  • carries hundred of tine teeth

• place the tip of the radula on food and pull the skin back and forth

• carnivores use radula to drill through shells

• herbivores use radula to scrape algae

Internal transport system of Gastropod

• Open circulatory system 

• Blood doesn't always travel inside blood vessels 

• works its way through the tissues in open spaces called CAVITIES 

Movement of Gastropods

Move with a broad, muscular foot located on their stomach which contracts 

Excretion of Gastropods

• Solid waste passes through anus in feces 

• Ammonia is filtered from the blood by Nephridia 

Reproduction of Gastropods

• Internal fertilization in the female 

• Hermaphrodites pair and fertilize each other's eggs at the same time 

Response of Gastropods

• 6 pairs of ganglia connected by major nerve chord

• decently well-developed

Trochophore

special mollusk larva

Mantle

thin tissue layer that covers the body

visceral mass

soft portion of organism that contains internal organs

Mollusk

soft-bodied animals that have an internal or external shell

shell

made by glands in the mantle that secrete CaCO3

how do Gastropods protect themselves?

• hide under things

• ink

• swim away

• shell

• poisonous chemicals

• nematocysts

How do cephalopods protect themselves?

• release ink/smoke screen

• camouflage

• speed/jet propulsion

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