Question 1

Which of the following is a key characteristic that distinguishes mollusks from other invertebrate phyla?

Accepted Answer

Presence of a hard shell made of calcium carbonate

Question 2

Chitons (Class Polyplacophora) are unique among mollusks because they have multiple plates on their dorsal surface. How many plates are typically found on a chiton, and what is their function?

Accepted Answer

8 plates; they provide flexibility and protection

Question 3

Which structure in gastropods is used for feeding and is often described as a 'rasping tongue'?

Accepted Answer

Radula

Question 4

Bivalves lack a radula. What is the primary reason for this anatomical difference compared to other mollusks?

Accepted Answer

They use filter feeding with cilia and gills instead of scraping food

Question 5

Cephalopods are known for their advanced nervous systems and complex behaviors. Which anatomical feature is most directly associated with their ability to move rapidly and evade predators?

Accepted Answer

Jet propulsion using the siphon

Question 6

Squids have a thin and flexible internal pen instead of a calcium carbonate shell. What is the main advantage of this adaptation?

Accepted Answer

It allows for greater speed and maneuverability in water

Question 7

Nematodes are classified as pseudocoelomates. What does this mean regarding their body cavity?

Accepted Answer

They have a body cavity that is not completely lined by mesoderm

Question 8

Some nematodes are parasitic. Which of the following is a common adaptation found in parasitic nematodes?

Accepted Answer

Production of a cuticle for protection against host defenses

Question 9

Annelids are segmented worms. What is the name of the repeating body unit that is responsible for segmentation in annelids?

Accepted Answer

Metamere

Question 10

Earthworms possess a clitellum. What is the function of the clitellum in earthworms?

Accepted Answer

It secretes mucus that holds mating earthworms together and forms the cocoon for eggs

Question 11

Leeches are annelids that produce anesthetics, anticoagulants, and vasodilators. What is the medical significance of these substances?

Accepted Answer

They allow leeches to feed on blood without detection and prevent clotting

Question 12

Which of the following best describes the respiratory system of bivalves?

Accepted Answer

They use gills to exchange gases and filter food particles from water

Question 13

A student observes a preserved specimen with a dorsoventrally flattened body, a reduced head, and visible suckers. Which annelid class does this specimen most likely belong to?

Accepted Answer

Class Hirudinea (leeches)

Question 14

Which equation best represents the process of gas exchange in aquatic bivalves?

Accepted Answer

$$O_2$$ \ (water) \rightarrow $$O_2$$ \ (blood)$$

Question 15

Which of the following is a major advantage of being monoecious (hermaphroditic) in earthworms?

Accepted Answer

Any two individuals can mate, increasing reproductive success

Question 16

Cephalopods such as squids and octopuses have highly developed eyes. What is the evolutionary advantage of this trait?

Accepted Answer

It allows them to detect prey and predators in complex environments

Question 17

Which of the following statements about nematode movement is correct?

Accepted Answer

Nematodes move by thrashing their bodies using longitudinal muscles

Question 18

A scientist discovers a marine animal with a closed circulatory system, a siphon, and tentacles with suckers. To which class does this animal most likely belong?

Accepted Answer

Class Cephalopoda

Question 19

Which of the following is a function of the adductor muscles in bivalves?

Accepted Answer

They close the two shells tightly for protection

Question 20

Earthworms are restricted to moist environments. What is the primary reason for this ecological limitation?

Accepted Answer

They respire through their skin, which must remain moist for gas exchange

Diversity and Anatomy of Invertebrate Animal Phyla: Mollusca, Nematoda, and Annelida

Study Guide - Practice Questions

Study Guide - Flashcards