phylum annelida and mollusca

Question 1

What are lower coelomates also called?

Answer 1

Protostomes.

Question 2

What are the characteristics of lower coelomates?

Answer 2

They have a true coelom, complete digestive tract, and well-developed nervous, excretory, and circulatory systems.

Question 3

Name three examples of lower coelomates.

Answer 3

Annelids, Molluscs, Arthropods.

Question 4

What is the function of the coelom?

Answer 4

It acts as a fluid-filled space that cushions internal organs and allows independent organ movement.

Question 5

How does the coelom help in movement?

Answer 5

It serves as a hydrostatic skeleton in soft-bodied animals.

Question 6

What role does the coelom play in organ development?

Answer 6

It provides space for gonads to develop.

Question 7

How does the coelom aid in material transport?

Answer 7

Coelomic fluid transports food, oxygen, and waste between cells.

Question 8

What is a major challenge of living on land?

Answer 8

Preventing dehydration in the absence of a surrounding water medium.

Question 9

How do land animals prevent dehydration?

Answer 9

They have body coverings that minimize fluid loss, and internal respiratory structures like lungs and tracheal tubes.

Question 10

Why do land animals need support structures?

Answer 10

To counteract the pull of gravity in the absence of buoyancy from water.

Question 11

How do molluscs and arthropods support their bodies?

Answer 11

They have a tough exoskeleton.

Question 12

How do vertebrates support their bodies?

Answer 12

They have an internal endoskeleton.

Question 13

Why do many land animals engage in internal fertilization?

Answer 13

To protect gametes and embryos from drying out.

Question 14

What is metamerism?

Answer 14

The division of the body into repeated segments.

Question 15

What external feature marks annelid segments?

Answer 15

Circular rings called annuli.

Question 16

What is the function of chaetae or setae in annelids?

Answer 16

They aid in movement and provide traction.

Question 17

Where do annelids live?

Answer 17

Marine, freshwater, and damp soil environments.

Question 18

What are the three main classes of annelids?

Answer 18

Polychaeta, Oligochaeta, Hirudinea.

Question 19

What is a unique feature of polychaetes?

Answer 19

They have parapodia with many setae.

Question 20

What are the two morphological groups of polychaetes?

Answer 20

Sedentary polychaetes and Errant polychaetes.

Question 21

What is a common example of an oligochaete?

Answer 21

Earthworm (Lumbricus terrestris).

Question 22

How do earthworms move?

Answer 22

By peristaltic contractions of their circular and longitudinal muscles.

Question 23

What is the role of the clitellum in earthworms?

Answer 23

It secretes mucus during reproduction and forms a cocoon for fertilized eggs.

Question 24

What is a key difference between leeches and other annelids?

Answer 24

Leeches lack setae and have suckers for movement.

Question 25

What is the scientific name of the medicinal leech?

Answer 25

Hirudo medicinalis.

Question 26

What are the main body parts of mollusks?

Answer 26

Head, muscular foot, and visceral mass covered by a mantle.

Question 27

What is the radula used for in mollusks?

Answer 27

It is a tongue-like structure with teeth used for feeding.

Question 28

What is torsion in gastropods?

Answer 28

A 180-degree twisting of the visceral mass.

Question 29

What adaptation allows some gastropods to breathe on land?

Answer 29

The mantle functions as a lung (pulmonate respiration).

Question 30

What are examples of bivalves?

Answer 30

Clams, mussels, scallops, oysters.

Question 31

What is pearl production in bivalves?

Answer 31

A protective reaction where the mantle secretes layers of nacre around an irritant.

Question 32

Which mollusks belong to the class Cephalopoda?

Answer 32

Squids, octopuses, cuttlefish, nautiluses.

Question 33

What is unique about cephalopods compared to other mollusks?

Answer 33

They have a closed circulatory system and highly developed nervous system.

Question 34

Why are mollusks economically important?

Answer 34

They provide food, pearls, lime for poultry, and some act as intermediate hosts for parasites.

Question 35

What defines a protostome?

Answer 35

An animal in which the mouth develops before the anus during embryonic development.

Question 36

What are the key features of lower coelomates?

Answer 36

They are triploblastic, bilaterally symmetrical, and have a complete digestive tract.

Question 37

How does the coelom contribute to locomotion?

Answer 37

It provides a hydrostatic skeleton for movement in soft-bodied animals.

Question 38

How does the coelom aid in circulation?

Answer 38

The coelomic fluid distributes nutrients, oxygen, and waste products between tissues.

Question 39

How do terrestrial animals reduce water loss?

Answer 39

Through specialized body coverings like exoskeletons, scales, or waterproof skin.

Question 40

Why is the location of respiratory surfaces important?

Answer 40

To prevent excessive water loss, many land animals have internal respiratory structures like lungs or tracheae.

Question 41

What is the function of the septa in annelids?

Answer 41

Septa divide the coelom into compartments, allowing independent muscle movement.

Question 42

What is a hydrostatic skeleton?

Answer 42

A fluid-filled structure that provides support and aids in movement.

Question 43

What is the prostomium in annelids?

Answer 43

The first body segment that contains sensory structures but not the mouth.

Question 44

What is the pygidium in annelids?

Answer 44

The last body segment that contains the anus.

Question 45

What are the key features of Polychaeta?

Answer 45

They have parapodia, numerous setae, and are mostly marine.

Question 46

What are parapodia used for?

Answer 46

Locomotion, respiration, and sometimes burrow maintenance.

Question 47

What is an example of a sedentary polychaete?

Answer 47

Tube-dwelling worms like feather duster worms.

Question 48

What is an example of an errant polychaete?

Answer 48

Clam worms (Nereis spp.).

Question 49

What do oligochaetes feed on?

Answer 49

Decaying organic matter, leaves, and other detritus.

Question 50

What is the importance of earthworms to soil?

Answer 50

They aerate the soil and enhance nutrient cycling.

Question 51

What do leeches feed on?

Answer 51

Some are carnivorous, others are bloodsucking parasites.

Question 52

How do leeches consume blood?

Answer 52

They use sharp jaws and secrete anticoagulants to prevent clotting.

Question 53

How many living species of Mollusca exist?

Answer 53

Over 90,000 known species.

Question 54

What is the mantle in mollusks?

Answer 54

A specialized tissue that secretes the shell in many mollusks.

Question 55

What is the largest class of mollusks?

Answer 55

Gastropoda, with over 70,000 species.

Question 56

What is the primary mode of movement in gastropods?

Answer 56

Using a muscular foot that secretes mucus for gliding.

Question 57

How do bivalves feed?

Answer 57

They are filter feeders, using gills to capture food particles from the water.

Question 58

What is the main structural characteristic of bivalves?

Answer 58

They have two hinged shells (valves).

Question 59

What is the largest invertebrate?

Answer 59

The giant squid (Architeuthis spp.), which can reach 60 feet in length.

Question 60

How do cephalopods move?

Answer 60

Using jet propulsion by expelling water through a siphon.

Question 61

What are chromatophores in cephalopods?

Answer 61

Pigment cells that allow cephalopods to change color for camouflage or communication.

Question 62

What type of circulatory system do cephalopods have?

Answer 62

A closed circulatory system, unlike other mollusks.

Question 63

What are pearls made of?

Answer 63

Layers of nacre secreted by the mantle of bivalves around an irritant.

Question 64

Which mollusk is commonly used in pearl culture?

Answer 64

The oyster species Meleagrina.

Question 65

How do mollusks benefit agriculture?

Answer 65

Some mollusk shells are used as a source of lime for poultry feed.