Question 1

Which of the following best explains why segmentation is considered an evolutionary advantage in annelids and arthropods?

Accepted Answer

Segmentation enables specialization of body regions, allowing for more efficient movement and organ function.

Question 2

A marine biologist discovers a new invertebrate species with the following characteristics: bilateral symmetry, three germ layers, a body cavity completely lined with mesoderm, and a closed circulatory system. To which group does this organism most likely belong?

Accepted Answer

Coelomates

Question 3

Which of the following is a key difference between protostome and deuterostome development?

Accepted Answer

Protostomes develop a mouth from the blastopore, while deuterostomes develop an anus from the blastopore.

Question 4

Which of the following structures is unique to members of the phylum Mollusca and is responsible for secreting the shell?

Accepted Answer

Mantle

Question 5

A student is examining a cross-section of a sponge under the microscope. Which cell type is responsible for generating water flow and capturing food particles?

Accepted Answer

Choanocytes

Question 6

Which of the following best describes the digestive system of a flatworm (Platyhelminthes)?

Accepted Answer

A gastrovascular cavity with a single opening

Question 7

Which of the following is a shared derived characteristic (synapomorphy) of the phylum Cnidaria?

Accepted Answer

Presence of cnidocytes

Question 8

Which of the following best explains why pseudocoelomates, such as nematodes, are evolutionarily significant?

Accepted Answer

They possess a body cavity not completely lined by mesoderm, allowing for a hydrostatic skeleton and more efficient movement.

Question 9

Which of the following is a correct comparison between the excretory systems of Platyhelminthes and Annelida?

Accepted Answer

Platyhelminthes use protonephridia (flame cells), while Annelida use metanephridia for excretion.

Question 10

Which of the following best describes the evolutionary advantage of a hydrostatic skeleton in soft-bodied invertebrates?

Accepted Answer

It allows for movement through the contraction of longitudinal and circular muscles against a fluid-filled cavity.

Question 11

A researcher is studying an animal with the following features: radial symmetry, two germ layers, and a gastrovascular cavity. Which phylum does this animal most likely belong to?

Accepted Answer

Cnidaria

Question 12

Which of the following is a distinguishing feature of the alimentary canal compared to the gastrovascular cavity?

Accepted Answer

The alimentary canal has two openings, allowing for unidirectional food processing.

Question 13

Which of the following is true regarding the nervous system evolution in invertebrates?

Accepted Answer

Cnidarians possess a nerve net, while more complex invertebrates like annelids have a ventral nerve cord and cerebral ganglia.

Question 14

Which of the following reproductive strategies is most likely to be found in sessile aquatic invertebrates such as sponges?

Accepted Answer

Asexual reproduction by budding or fragmentation

Question 15

Which of the following best explains why the evolution of a coelom was a significant step in animal evolution?

Accepted Answer

It allowed for the development of more complex and specialized organs by providing a fluid-filled space for organ suspension and movement.

Question 16

Which of the following is a correct pairing of animal phylum and its defining characteristic?

Accepted Answer

Porifera – presence of choanocytes

Question 17

Which of the following best describes the function of Malpighian tubules in arthropods?

Accepted Answer

They remove nitrogenous wastes from the hemolymph and help conserve water.

Question 18

A zoologist is comparing the respiratory systems of different invertebrate phyla. Which of the following is true?

Accepted Answer

Many aquatic annelids exchange gases directly through their skin, while terrestrial arthropods use tracheal systems.

Question 19

Which of the following statements about animal symmetry is correct?

Accepted Answer

Radial symmetry is typically found in animals that are sessile or planktonic, such as cnidarians.

Question 20

Which of the following best describes the evolutionary relationship among major animal phyla?

Accepted Answer

They share a common ancestor and are related through descent with modification, as shown in cladograms based on shared derived characteristics.

Invertebrate Animals: Structure, Function, and Evolutionary Diversity

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