Q: Which of the following equations best represents the calculation of Degree Heating Weeks (DHW) used to predict coral bleaching?

$\sum_{i=1}^{n} (T_i - T_{mean}) \times \frac{1}{7}$

Question 1

Which of the following statements best describes the organization of Porifera (sponges)?

Accepted Answer

They are multicellular but lack true tissues and organs.

Question 2

What is the primary function of choanocytes in sponges?

Accepted Answer

Generating water currents and capturing food particles.

Question 3

Which of the following is TRUE regarding the embryonic development of sponges?

Accepted Answer

Sponges do not produce a gastrula and lack true germ layers.

Question 4

Cnidarians are classified as diploblastic organisms. What does this mean?

Accepted Answer

They have two germ layers: ectoderm and endoderm.

Question 5

Which structure in cnidarians acts as both a mouth and an anus?

Accepted Answer

Single opening at the mouth

Question 6

What is the main ecological significance of coral reefs formed by cnidarians?

Accepted Answer

They provide habitat for approximately 25% of marine species.

Question 7

Which cell type in cnidarians contains the stinging organelle used for prey capture?

Accepted Answer

Cnidocyte

Question 8

A scientist observes a marine animal with radial symmetry, two tissue layers, and a gastrovascular cavity. Which phylum does this animal most likely belong to?

Accepted Answer

Cnidaria

Question 9

Which of the following best explains why sponges are considered filter feeders?

Accepted Answer

They draw water through pores and trap food particles with choanocytes.

Question 10

Coral bleaching is most likely to occur when which of the following conditions is met?

Accepted Answer

Degree Heating Weeks (DHW) exceeds 8 within a 12-week period.

Question 11

Which of the following is a key difference between the polyp and medusa forms in cnidarians?

Accepted Answer

Polyps are sessile, while medusae are free-swimming.

Question 12

Which of the following equations best represents the calculation of Degree Heating Weeks (DHW) used to predict coral bleaching?

Accepted Answer

$\sum_{i=1}^{n} (T_i - T_{mean}) 	imes \frac{1}{7}$

Question 13

Which of the following is a plausible consequence of widespread coral bleaching for human populations?

Accepted Answer

Loss of food sources, tourism revenue, and coastal protection.

Question 14

Which of the following statements about sponge reproduction is correct?

Accepted Answer

Sponges can produce both eggs and sperm, often in the same individual.

Question 15

Which of the following is NOT a characteristic of Cnidarians?

Accepted Answer

Presence of a coelom

Question 16

Which of the following best describes the role of zooxanthellae in coral reefs?

Accepted Answer

They are photosynthetic protists that provide nutrients to corals.

Question 17

A student claims that sponges are closely related to choanoflagellates. Which evidence supports this claim?

Accepted Answer

Both possess choanocyte-like cells with flagella for feeding.

Question 18

Which of the following is a plausible reason why jellyfish populations might appear to be increasing globally?

Accepted Answer

Flawed data collection and sensationalized media reports.

Question 19

Which of the following best explains why sponges are not classified as Eumetazoa?

Accepted Answer

They lack true tissues and do not undergo gastrulation.

Question 20

During mass spawning events in coral reefs, what is the evolutionary advantage of synchronous release of gametes?

Accepted Answer

It increases the likelihood of fertilization by maximizing gamete encounters.

Sponges & Cnidarians: Structure, Function, and Diversity (Chapter 30 Study Notes)

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