Quiz: Introduction to Mollusca Biology — 9 Fragen

1. Which of the following best describes the main body regions of a mollusk?

A. Anterior, posterior, dorsal, ventral

B. Cephalothorax and abdomen

C. Head-foot, visceral mass, mantle

D. Segmented body with jointed appendages

Answer: (C)

Erklärung

The main body regions of a mollusk include the head-foot (sensory and locomotor functions), visceral mass (containing most organs), and mantle (which secretes the shell). These regions are characteristic of molluscan anatomy.

2. Which molluscan class was described by H. G. Matthews and A. L. Newman in 1962 as having the most advanced nervous system among mollusks?

A. Polyplacophora

B. Gastropoda

C. Cephalopoda

D. Bivalvia

Answer: (C)

Erklärung

Cephalopods are known for their highly developed nervous system and complex brains, as highlighted by Matthews and Newman in 1962, setting them apart from other molluscan classes.

3. What is the primary composition of the mollusk shell, and which part secretes it?

A. Chitin, secreted by the foot

B. Calcium phosphate, secreted by the visceral mass

C. Calcium carbonate, secreted by the mantle

D. Silica, secreted by the radula

Answer: (C)

Erklärung

Most mollusk shells are composed of calcium carbonate, which is secreted by the mantle tissue. This shell provides protection and structural support.

4. In mollusks, which reproductive characteristic is true for the majority of species?

A. Most are hermaphroditic

B. Most are dioecious

C. All have external fertilization

D. Reproduction involves live birth in most cases

Answer: (B)

Erklärung

The majority of mollusks are dioecious, meaning they have separate sexes, although some species are hermaphroditic; this is a key reproductive trait among molluscs.

5. Which class of mollusks is characterized by having a highly developed nervous system and closed circulatory system?

A. Gastropoda

B. Cephalopoda

C. Bivalvia

D. Polyplacophora

Answer: (B)

Erklärung

Cephalopods, such as squids and octopuses, possess a highly developed nervous system and a closed circulatory system, which are adaptations for their active predatory lifestyle.

6. What is the main structural component secreted by the mantle of mollusks to form their shells?

A. Silica

B. Calcium carbonate

C. Chitin

D. Limestone

Answer: (B)

Erklärung

The shell of mollusks is primarily composed of calcium carbonate secreted by the mantle, providing protection and structural support.

7. Which of the following is NOT typically a primary component of the molluscan body plan?

A. Mantle

B. Radula

C. Exoskeleton made of chitin

D. Foot

Answer: (C)

Erklärung

Mollusks do not have an exoskeleton made of chitin; instead, they have a calcium carbonate shell, and their body plan includes the mantle, radula (except bivalves), and foot.

8. In which classes of mollusks is the circulatory system open?

A. Cephalopoda and Polyplacophora

B. Gastropoda and Bivalvia

C. Cephalopoda and Bivalvia

D. Polyplacophora and Bivalvia

Answer: (B)

Erklärung

Gastropods and bivalves have an open circulatory system, where hemolymph bathes the organs directly, whereas cephalopods have a closed system for efficient oxygen transport.

9. What larval stages do mollusks go through during their development?

A. Egg and nymph stages

B. Trochophore and veliger stages

C. Caterpillar and chrysalis stages

D. Larva and pupa stages

Answer: (B)

Erklärung

Mollusks develop through planktonic larval stages called trochophore and veliger, which are important for dispersal and development.