Question 1

Refer to the figure.  Which statement about the body plan of the larval and adult sea star is true?

Accepted Answer

E

Question 2

Which of the following about radial cleavage is true?

Accepted Answer

Radial cleavage is the ancestral condition for the bilaterians.

Question 3

Which of the following groups has a water vascular system?

Accepted Answer

Echinoderms, such as starfish and sea urchins, have a unique water vascular system that helps them with movement and feeding.

Question 4

The _______ of a sea star, a type of echinoderm, is on the upper surface of the animal.When a sea star is resting on the sea floor, its _______ faces the sea floor.

Accepted Answer

The anus of a sea star is located on the upper surface of its body and the mouth is on the underside. Therefore, when the sea star is resting on the sea floor, its anus faces downward towards the sea floor.

Question 5

Which of the following is not a characteristic of deuterostomes?

Accepted Answer

This statement is actually incorrect. Protostomes have a greater number of species than deuterostomes. Therefore, the characteristic that is not associated with deuterostomes is not having a greater number of species than protostomes.

Question 6

The _______ are likely closely related to the most recent common ancestors of all deuterostomes.

Accepted Answer

Yunnanozoans are considered to be closely related to the most recent common ancestors of all deuterostomes, based on fossil evidence and their anatomical features that suggest a link between early deuterostomes and this group.

Question 7

You find a fossil deuterostome in marine deposits, that has several feathery arms at the end of a long stalk.The stalk is composed of tiny discs that resemble a five-pointed star in cross section.This animal is likely a

Accepted Answer

The feathery arms at the end of a long stalk and the tiny discs resembling a five-pointed star in cross section are characteristic of crinoids, which are a type of deuterostome. The other options do not fit this description. Asterozoans include starfish, which do not have a long stalk, and echinozoans include sea urchins, which also do not have a stalk. Hemichordates are worm-like organisms and lancelets are chordates that do not have stalks or feathery arms.

Question 8

A calcified internal skeleton is characteristic of the

Accepted Answer

Echinoderms are known for their calcified internal skeleton, which gives them their distinctive spiny appearance. Urochordates, hemichordates, brachiopods, and phoronids do not have this feature.

Question 9

Refer to the figure.  Which characteristic is shared by all the animals shown in the figure?

Accepted Answer

The answer of Refer to the figure.  Which characteristic...

Question 10

Which of the following is not a characteristic of echinoderms?

Accepted Answer

Echinoderms have an internal skeleton of calcified plates, not an external skeleton of chitin.

Question 11

Living deuterostomes comprise three clades: the echinoderms, the chordates, and the

Accepted Answer

Hemichordates, along with echinoderms and chordates, are one of the three main clades of living deuterostomes. Urochordates and cephalochordates are subgroups within chordates, vertebrates are a more specific group within chordates, and yunnanozoans are an extinct group whose classification is debated but they are not considered a main living clade of deuterostomes.

Question 12

Which of the following echinoderms does not use tube feet for locomotion?

Accepted Answer

Sea lilies do not use tube feet for locomotion. They are sessile and anchored to the ocean floor by a stalk, and they use their tube feet to capture food particles that float by on the currents. The other options all use tube feet for locomotion.

Question 13

In _______, the coelom arises from _______ and the _______ arises from the blastopore.

Accepted Answer

In deuterostomes, the coelom forms from mesodermal outpocketings of the archenteron, and the anus develops from the blastopore.

Question 14

A _______ that develops from mesodermal pockets that bud off from the cavity of the gastrula is a characteristic of _______.

Accepted Answer

The development of a coelom from mesodermal pockets is a characteristic of deuterostomes, not protostomes. Therefore, choices A, D, and E can be eliminated. The gastrovascular cavity is a characteristic of animals with a simple body plan, like cnidarians, whereas deuterostomes are more complex and have a more advanced body plan that includes a coelom. Therefore, choice B can also be eliminated.

Question 15

Fossil evidence indicates that the earliest deuterostomes were bilaterally symmetrical, segmented animals with a pharynx that had slits through which water flowed.Adult echinoderms have pentaradial (five-radial) symmetry.Therefore,

Accepted Answer

Adult pentaradial symmetry in echinoderms is a derived character because the earliest deuterostomes, from which echinoderms evolved, were bilaterally symmetrical. This indicates that the shift to pentaradial symmetry in adult echinoderms represents a significant evolutionary change from their ancestral state.

Question 16

Since echinoderms and hemichordates both have ciliated larvae that are bilaterally symmetrical, they are both classified as

Accepted Answer

Both echinoderms and hemichordates are classified as ambulacrarians due to their shared characteristics of having a water vascular system, a calcareous endoskeleton, and a pentaradial symmetry in adults. The ciliated larvae that are bilaterally symmetrical are a shared ancestral characteristic.

Question 17

Which of the following did not occur in both the protostomes and deuterostomes?

Accepted Answer

Evolution of large terrestrial species occurred only in deuterostomes, specifically in the lineage that includes mammals. Protostomes, on the other hand, have not evolved large terrestrial species.

Question 18

Which of the following observable characteristics places the yunnanozoan fossils in the deuterostome group?

Accepted Answer

Pharyngeal slits are a characteristic feature of deuterostomes, which include groups like chordates. Yunnanozoans are considered to be early deuterostomes, and the presence of pharyngeal slits supports this classification.

Question 19

Which echinoderm group lacks "arms"?

Accepted Answer

Sea cucumbers lack "arms," distinguishing them from other echinoderms like sea stars, brittle stars, sea feathers, and sea lilies, which all have arm-like structures.

Question 20

A water vascular system may be advantageous in echinoderms because

Accepted Answer

The water vascular system in echinoderms allows them to perform the functions of gas exchange, locomotion, and feeding, all with one system. This would be advantageous for these organisms, as it decreases the amount of energy and resources needed for multiple systems.

Quiz 32: Deuterostome Animals

Refer to the figure. Which statement about the body plan of the larval and adult sea star is true?