Squids & Octopus (Cephalopoda) Quiz

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Questions and Answers

What is the primary function of the radula in snails?

To filter particles of food from water

To grasp and manipulate food (correct)

To secrete the shell

To burrow into the sea bottom

What is unique about the respiratory system of pulmonates?

They have a book-lung for respiration

They have a lung for respiration (correct)

They have gills for respiration

They use their radula for gas exchange

What is the composition of the shell in snails?

Protein and keratin

Silica and calcium carbonate

Calcium carbonate only (correct)

Chitin and calcium carbonate

What is the larval stage of snails?

Ciliated trochophore Signup and view all the answers

What is the primary mode of feeding in bivalves?

Filter-feeding using gills Signup and view all the answers

What is the characteristic feature of the circulatory system in mollusks?

Open circulatory system with a haemocoel Signup and view all the answers

Where does the larval stage of Trichinella occur?

In pigs Signup and view all the answers

What is the function of radula in snails and chitons?

It is used for scraping algae off rocks Signup and view all the answers

What is a characteristic of chitons?

They have a row of gills around their foot Signup and view all the answers

What is the location of the adult Trichinella parasite in humans?

In skeletal muscle cells Signup and view all the answers

What is a feeding behavior of some Molluscs?

Drilling through shells of prey Signup and view all the answers

How do some land-dwelling Molluscs breathe?

Using a lung Signup and view all the answers

What is the primary mode of locomotion for squids and octopuses?

Jet propulsion by squirting water out of their mantle cavity Signup and view all the answers

Which of the following is a characteristic of annelids?

Tubular body divided into segments with a hydrostatic skeleton Signup and view all the answers

What is unique about the circulatory system of squids and octopuses?

They have a double circulation with three hearts Signup and view all the answers

What is the main function of the parapodia in polychaetes?

Crawling over the sea bottom Signup and view all the answers

What is the main difference between polychaetes and earthworms?

One has parapodia and the other does not Signup and view all the answers

What is the function of the radula in squids and octopuses?

To cut up food into small pieces Signup and view all the answers

Study Notes

Cephalopoda (Squids & Octopuses)

Advanced active predators with a streamlined body and stabilizing fins
Fast swimmers using jet propulsion, squirting a jet of water out of the mantle cavity
Excellent eyesight and very large brain, making them highly intelligent
Well-developed closed blood system with a double circulation and three hearts
Foot replaced by 10 tentacles covered in suckers to hold slippery fish
Inject poison to kill fish, then cut them up with a pair of jaws and use radula to pull pieces into the mouth

Annelida (Segmented Worms)

Tubular body divided into segments, an adaptation for burrowing
Burrow using a hydrostatic skeleton, with a water-filled coelom enclosed in two layers of muscles
Well-developed closed blood system with arteries, veins, and five hearts
Have a dorsal brain, ventral nerve, and ganglia in each segment
Excretion by metanephridia
Breathe through the skin
Have a clitellum that aids in reproduction

Annelid Classes

Polychaeta: most primitive, live in the sea, and crawl over the sea bottom using parapodia and chaetae on each segment
Oligochaeta (Earthworms): live on land or in freshwater, adapted for burrowing, and have no parapodia and no head

Mollusca (Snails)

More advanced phylum with a coelom and true gut
Characteristics:
- Shell of CaCO3
- Body divided into: head, foot, mantle (secretes shell), and visceral mass
- Radula: a chitin rod covered in rows of teeth, used for feeding
- Only sexual reproduction (dioecious): egg → ciliated trochophore larva
- Advanced nervous system (brain + separate nerves), but primitive blood system (open blood circulatory system with haemocoel)

Molluscan Classes

Bivalves: mainly live in the sea, burrow in the sea bottom using a wedge-shaped foot, and have a shell with 2 valves completely enclosing the body
Chitons (Polyplacophora): most primitive, live in the sea, and have a shell consisting of 8 plates
Snails (Gastropoda): large diverse group, crawl using a large flat foot, and have a distinct head with tentacles and eyes

Nematoda (Round Worms)

Trichinella has its larval stage in pigs (secondary host), and can enter humans through eating infected pork
The adult is an intracellular parasite inside a skeletal muscle cell, and secretes chemicals to:
- Cause the skeletal muscle cell to expand
- Attract blood vessels to the cell to improve its O2 supply

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Description

Test your knowledge on squids and octopus, advanced active predators with unique features like jet propulsion, excellent eyesight, and intelligence. Learn about their anatomy, behavior, and adaptations for survival in the quiz.