Question 1

Which of the following best distinguishes Ecdysozoa from Lophotrochozoa?

Accepted Answer

Ecdysozoans undergo molting (ecdysis) of a cuticle or exoskeleton during growth, while Lophotrochozoans do not.

Question 2

Which adaptation has most directly enabled multiple protostome lineages to successfully transition from aquatic to terrestrial environments?

Accepted Answer

Development of structures to minimize water loss, such as a waxy cuticle or shell.

Question 3

Which of the following is a key reason why the water-to-land transition has occurred multiple times independently in protostome evolution?

Accepted Answer

Terrestrial habitats offered new ecological opportunities and reduced competition.

Question 4

Which feature is shared by all members of the Lophotrochozoa?

Accepted Answer

Presence of either a lophophore or a trochophore larva during development.

Question 5

A scientist discovers a small aquatic animal with a ciliated structure called a corona used for feeding and locomotion. To which phylum does this animal most likely belong?

Accepted Answer

Rotifera

Question 6

Which of the following best describes the modular body plan of arthropods and its significance in their evolutionary diversification?

Accepted Answer

The segmentation and specialization of body regions (tagmata) allowed for the evolution of diverse appendages and functions.

Question 7

Which of the following is NOT a characteristic of the phylum Mollusca?

Accepted Answer

Presence of chaetae for locomotion.

Question 8

Which morphological feature is unique to the class Cephalopoda within the Mollusca?

Accepted Answer

A beak-like jaw and highly developed nervous system.

Question 9

Which of the following best explains why nematodes are considered ecdysozoans?

Accepted Answer

They molt a collagen-based cuticle as they grow.

Question 10

A researcher is studying an animal with the following characteristics: segmented body, chaetae, and a hydrostatic skeleton. To which phylum does this animal most likely belong?

Accepted Answer

Annelida

Question 11

Which of the following is a key difference between holometabolous and hemimetabolous insects?

Accepted Answer

Holometabolous insects undergo complete metamorphosis with a pupal stage, while hemimetabolous insects do not.

Question 12

Which of the following is an example of a holometabolous insect?

Accepted Answer

Butterfly

Question 13

Which of the following best describes the ecological role of bivalves within the Mollusca?

Accepted Answer

They are filter feeders that play a key role in aquatic nutrient cycling.

Question 14

Which of the following statements about arthropod body plans is correct?

Accepted Answer

Arthropods have a segmented body divided into tagmata, such as head, thorax, and abdomen.

Question 15

Which of the following is a defining feature of the Chelicerata within the Arthropoda?

Accepted Answer

Presence of chelicerae (specialized mouthparts) and a cephalothorax.

Question 16

Which of the following best explains the evolutionary advantage of metamorphosis in insects?

Accepted Answer

It allows larvae and adults to occupy different ecological niches, reducing competition for resources.

Question 17

Which of the following is a characteristic of tardigrades (water bears)?

Accepted Answer

They can survive extreme environmental conditions by entering a cryptobiotic state.

Question 18

Which of the following best describes the function of the mantle in mollusks?

Accepted Answer

It secretes the shell and forms a cavity for respiration and excretion.

Question 19

Which of the following is a key difference between the body plans of annelids and nematodes?

Accepted Answer

Annelids are segmented and have chaetae, while nematodes are unsegmented and lack chaetae.

Question 20

A marine biologist finds an animal with a soft, unsegmented body, a muscular foot, and a radula. Which class within the Mollusca is this animal most likely to belong to?

Accepted Answer

Gastropoda

Protostome Animals: Structure, Diversity, and Evolution

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