Question 1

Which of the following is a synapomorphy unique to the phylum Porifera (sponges)?

Accepted Answer

Presence of choanocytes with flagella

Question 2

What is the primary function of spicules in sponges?

Accepted Answer

Support and defense of the sponge's body

Question 3

Which of the following statements best explains why ctenophores are not grouped with cnidarians?

Accepted Answer

Ctenophores lack stinging cells and instead use colloblasts to capture prey

Question 4

A researcher discovers a new aquatic organism with the following features: multicellularity, choanocytes, spicules, and no true tissues. To which group does this organism most likely belong?

Accepted Answer

Phylum Porifera

Question 5

Which class of cnidarians is characterized by the absence of a medusa stage and the presence of endosymbiotic dinoflagellates?

Accepted Answer

Anthozoa

Question 6

Which of the following best describes the feeding mechanism of choanoflagellates and sponge choanocytes?

Accepted Answer

They use a collar of microvilli to trap food particles from water currents generated by their flagella

Question 7

Which of the following is a key evolutionary innovation that first appears in ctenophores but not in sponges or cnidarians?

Accepted Answer

A complete gut with separate mouth and anus

Question 8

A marine biologist observes a colonial organism with both medusa and polyp forms, living as a free-floating colony. To which class does this organism most likely belong?

Accepted Answer

Hydrozoa

Question 9

Which of the following statements about cnidarian nervous systems is correct?

Accepted Answer

Cnidarians possess a diffuse nerve net rather than a centralized nervous system

Question 10

Which of the following best explains how most corals in the class Anthozoa can thrive in nutrient-poor waters?

Accepted Answer

They form endosymbiotic relationships with photosynthetic dinoflagellates

Question 11

Which of the following is a defining feature of the phylum Ctenophora?

Accepted Answer

Presence of colloblasts for prey capture

Question 12

Which of the following is true regarding the body plan of sponges?

Accepted Answer

They have an inner layer of choanocytes and an outer layer containing collagen and spicules

Question 13

Which class of cnidarians is known for having complex eyes and highly potent venom that can cause cardiac arrest in humans?

Accepted Answer

Cubozoa

Question 14

Which of the following is a correct sequence of evolutionary innovations in early animal evolution?

Accepted Answer

Multicellularity → Collagen → Blastula → Choanocytes → Spicules → Diploblasty → Radial symmetry

Question 15

Which of the following best describes the difference between the gut of a cnidarian and a ctenophore?

Accepted Answer

Cnidarians have a two-way gut, while ctenophores have a complete gut with separate mouth and anus

Question 16

Which of the following is NOT a feature of choanoflagellates?

Accepted Answer

Presence of true tissues

Question 17

A student is examining a microscopic slide and observes cells with collars and flagella, but no evidence of multicellularity. Which group is the student most likely observing?

Accepted Answer

Choanoflagellates

Question 18

Which of the following is a unique feature of the class Scyphozoa among cnidarians?

Accepted Answer

Asexual reproduction via strobilation/budding

Question 19

Which of the following statements about the evolutionary relationships among non-bilaterian animals is supported by current evidence?

Accepted Answer

Ctenophores independently evolved a complete gut and a primitive CNS

Question 20

Which of the following best explains why the structure and shape of sponge spicules are important in biology?

Accepted Answer

They are used as taxonomic features to distinguish sponge species

Non-Bilaterian Animals: Porifera, Ctenophora, and Cnidaria

Guida di studio - Domande di pratica

Study guide - Flashcard