Question 1

There is evidence that ray-finned fishes evolved

Accepted Answer

The swim bladder, an organ that helps fish control their buoyancy, is believed to have evolved from a lung-like structure in early fish ancestors. This adaptation allowed fish to regulate their buoyancy in water more efficiently.

Question 2

Which of these statements accurately describes a similarity between sharks and ray-finned fishes?

Accepted Answer

Both sharks and ray-finned fishes have a lateral line, which is a sensory organ system that detects changes in water pressure and helps with orientation, detection of prey, and schooling behavior.

Question 3

Hagfish have slime glands that can produce large amounts of slime. What is an important function of slime production?

Accepted Answer

C

Question 4

The feeding mode of the extinct conodonts was

Accepted Answer

Conodonts were predatory and fed on small invertebrates, as evidenced by their anatomy and the presence of sharp teeth.

Question 5

Which group's members have had both lungs and gills during their adult lives?

Accepted Answer

Lungfishes are known to have both lungs and gills during their adult lives. Sharks, skates, and rays only have gills, lancelets only have pharyngeal gill slits, amphibians have lungs as adults but may have gills as larvae, and ichthyosaurs and plesiosaurs are extinct marine reptiles that breathed air with lungs.

Question 6

Which extant chordates are postulated to be most like the earliest chordates in appearance?

Accepted Answer

Lancelets, also known as amphioxus, are considered to be the most similar to the earliest chordates in appearance. They have a notochord, dorsal hollow nerve cord, and pharyngeal slits, which are all key characteristics of chordates. Adult tunicates, although also chordates, have undergone significant metamorphosis and do not possess all of these traditional chordate features in their adult form. Amphibians, reptiles, and chondrichthyans are all more advanced and have evolved beyond the basic characteristics of early chordates.

Question 7

Which of the following belongs to the lobe-fin clade?

Accepted Answer

The lobe-fin clade includes tetrapods (four-limbed vertebrates) as well as their closest living relatives, such as lungfish and coelacanths. Chondrichthyans, ray-finned fishes, lampreys, and hagfishes are not part of the lobe-fin clade.

Question 8

How many of the following statements about craniates is (are)correct? 1. Craniates are more highly cephalized than are noncraniates.
2. Craniates' genomic evolution includes duplication of clusters of genes that code for transcription factors.
3. The craniate clade is synonymous with the vertebrate clade.
4. Pharyngeal slits that play important roles in gas exchange originated in craniates.
5. The two-chambered heart originated with the early craniates.

Accepted Answer

Statements 1, 2, 3, and 4 are correct. Statement 5 is incorrect as the two-chambered heart originated with fish, which are a subset of craniates.

Question 9

Which of the following statements would be least acceptable to most zoologists?

Accepted Answer

Most zoologists would not accept the statement that the extant lancelets are the immediate ancestors of fishes as it contradicts the current understanding of vertebrate evolution.

Question 10

The earliest known mineralized structures in vertebrates are associated with which function?

Accepted Answer

The earliest known mineralized structures in vertebrates are associated with feeding, as the teeth of the extinct armoured fish called ostracoderms are the first known mineralized structures in the fossil record.

Question 11

To which of the following are the scales of chondrichthyans most closely related in a structural sense?

Accepted Answer

Chondrichthyan scales are actually modified teeth, and thus are most closely related to chondrichthyan teeth. The scales of other vertebrates, such as osteichthyans, reptiles, mammals, and birds, have a different structure and development.

Question 12

What do all craniates have that earlier chordates did not have?

Accepted Answer

Craniates have a partial or complete skull, which earlier chordates did not have. While they developed a cartilaginous pipe surrounding the notochord and eventually developed vertebrate, not all craniates have bone as some have cartilage. However, all craniates do have some form of skull which is what distinguishes them from earlier chordates.

Question 13

A new species of aquatic chordate is discovered that closely resembles an ancient form. It has the following characteristics: external armour of bony plates, no paired lateral fins, and a suspension-feeding mode of nutrition. In addition to these, it will probably have which of the following characteristics?

Accepted Answer

The absence of paired lateral fins suggests that this species has a primitive body plan, which is further supported by the presence of external armour of bony plates. Suspension-feeding mode of nutrition is also a primitive feeding strategy. The absence of jaws is also a primitive characteristic common in many ancient chordates, such as lampreys. Legs and amniotic eggs are characteristics found in higher vertebrates and are not expected in a primitive chordate. Endothermy is also a characteristic found in higher vertebrates and is unlikely to be present in a primitive aquatic chordate.

Question 14

Jaws first occurred in which extant group of fishes?

Accepted Answer

Jaws are a unique feature of chondrichthyans, which include sharks, rays, and chimaeras. Jaws evolved from the first pair of gill arches, and their development allowed chondrichthyans to become apex predators in their habitats.

Question 15

A team of researchers has developed a poison that has proven effective against lamprey larvae in freshwater cultures. The poison is ingested and causes paralysis by detaching segmental muscles from the skeletal elements. The team wants to test the poison's effectiveness in streams feeding Lake Michigan, but one critic worries about potential effects on lancelets, which are similar to lampreys in many ways. Why is this concern misplaced?

Accepted Answer

The answer of A team of researchers has developed a...

Question 16

The lamprey species whose larvae live in freshwater streams, but whose adults live most of their lives in sea water, are similar in this respect to certain species of

Accepted Answer

The fact that the lamprey species' larvae live in freshwater streams, but its adults live most of their lives in sea water is a characteristic shared by certain species of actinopterygians, or ray-finned fishes. Chondrichthyans, lungfishes, coelacanths, and hagfishes do not have this similar trait.

Question 17

Chordate pharyngeal slits appear to have functioned first as

Accepted Answer

Chordate pharyngeal slits initially functioned as suspension-feeding devices, where water is filtered for food particles. Later on, it evolved into gill slits for respiration in aquatic animals and formed components of the jaw and inner ear in terrestrial animals.

Question 18

Which of these might have been observed in the common ancestor of chondrichthyans and osteichthyans?

Accepted Answer

The answer of Which of these might have been observed...

Question 19

Lampreys differ from hagfishes in

Accepted Answer

The answer of Lampreys differ from hagfishes in
...

Question 20

The swim bladder of ray-finned fishes

Accepted Answer

The swim bladder of ray-finned fishes provides for regulation of buoyancy allowing the fish to control its depth in the water. It is not likely to have been modified from simple lungs of chondrichthyans or have developed into lungs in saltwater fishes. Nor did it first appear in sharks. Therefore, option D is the best choice.

Quiz 34: The Origin and Evolution of Vertebrates