Mollusks WorksheetRead pages 585-593 and answer the following questions

1. How long ago did the mollusks evolve? They evolved 600 million years ago.2. In what range do mollusks live? From deep ocean trenches to mountain brooks to the

tops of trees.3. Why are such different creatures classified together in one phylum? They all have a

trochophore larva and they are soft bodies animals that have an internal or external shell

4. What is the mollusk larva called? Trochophore larva5. Which other phylum also develop this same kind of larva? Phylum Annelida6. What does this indicate about mollusk evolution? Mollusks and Annelids are closely

related7. List some other reasons why mollusks are grouped together. Mollusk bodies have 4

basic parts;Foot, mantle, visceral mass and shell

8. Fill in the table below:Part DescriptionFoot Soft muscular structure that usually contains mouth and structures

associated with feedingShell Protective structure made of CaCO3(calcium carbonate)Visceral mass Contains the internal organsMantle Thin delicate layer that covers the mollusk body like a cloak

and secretes calcium carbonate for the shell.

9. What is a radula? The rasping tongue found in mollusks10. How is the radula used by a) carnivores? b) herbivores?

They use it to bore They use the radula to scrape algae off holes in the shells of rocks other mollusks

11.What do filter feeders use to gather food? They use their gills.12.Compare and contrast open and closed circulatory systems.

Same: Different:Carry blood In open circulatory systems blood does not always stay in blood vesselsDistribute O2 & nutrients while in closed circulatory systems blood always stays in blood vessels

13.Complete the table below about mollusk reproduction:Internal Fertilization External Fertilization

Where it takes place Inside the body Outside the bodyDescription of how it is done

Cephalopod fertilization takes place inside the female’s bodyHermaphroditic gastropods pair up and fertilize each other’s

Eggs and sperm are released into open water in enormous numbers

eggsOrganisms that use this form of reproduction

SnailsTentacled mollusks

Bivalves

14.In the diagram below:a. Colour the gut blueb. Colour the lungs red c. Colour the tentacles green d. Colour the eyes purplee. Colour the reproductive organs yellow f. This type of organism is called a/an _Hermaphrodite___g. Can you locate a major design flaw in this body design? The anus is near the respiratory pore

15.Describe the lifestyle of most bivalves. They live on the bottom of the ocean and burrow in sand or mud.

16.How do bivalves make pearls? If a grain of sand gets caught between the mantle and shell, the mantle glands cover it with mother of pearl. After many years the grain of sand gets completely coated and is called pearls.

17.Label the diagram of a clam below:

18.Describe the appendages of cephalopods. They have eight flexible tentacles equipped with round sucking disks that are used to grab and hold fish and other prey. In addition to the tentacles squids also have two long arms with suckers on the end.

19.Describe movement in cephalopods. They use jet propulsion by drawing water into their mantle cavities that they then force out through their tube like siphon.

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20.Decide of the organisms listed below are gastropods, bivalve, cephalopods or other (leave blank)

Organism Gastropod Bivalve Cephalopod

Nudibranch Cuttlefish Slug Clam Sea hares Mussel ChitonsOctopus Snail Shipworms Scallop Abalone Oyster