Question 1

Which chordate features in the sea squirt (tunicate) larva do not appear in the adult sea squirt?

Accepted Answer

Sea squirt (tunicate) larvae exhibit chordate features such as a hollow dorsal nerve cord, post-anal tail, and notochord, which are not present in the adult form.

Question 2

Hagfishes differ from lampreys in that

Accepted Answer

Hagfishes are primarily marine organisms, living in the ocean, whereas lampreys can be found in both freshwater environments and the ocean, with many species being anadromous, migrating to freshwater to spawn.

Question 3

Refer to the figure.  What modification in jaw structure has occurred in modern jawed fishes that was not present in early jawed fishes?

Accepted Answer

The answer of Refer to the figure.  What modification...

Question 4

The coelacanth is a modern lobe-limbed vertebrate that is also grouped as a(n)

Accepted Answer

The coelacanth is a gnathostome, a term that refers to jawed vertebrates. This group includes both modern species like sharks, bony fish, and tetrapods, as well as extinct species. The coelacanth is not a cyclostome (jawless vertebrates), chondrichthyan (cartilaginous fishes), eutherian (placental mammals), or a tetrapod (four-limbed vertebrates with backbones).

Question 5

Refer to the figure.  How do the adults of the species in the figure differ from their larvae?

Accepted Answer

The answer of Refer to the figure.  How do...

Question 6

Which statement about the vulnerability of most modern amphibians to environmental change is true?

Accepted Answer

Most modern amphibians have thin skin which makes them vulnerable to losing water rapidly when exposed to dry air. This means that changes in the environment, such as increased temperature or decreased humidity, can be detrimental to their survival.

Question 7

Refer to the figure.  The figure shows a _______ at the _______ life cycle stage.

Accepted Answer

The figure shows a sea squirt (tunicate) at the larval stage. This can be identified by the tadpole-like shape and the presence of a tail, which are characteristic features of the larval stage of sea squirts.

Question 8

The sharks, skates, and rays possess all of the following characteristics except

Accepted Answer

Sharks, skates, and rays have dermal denticles instead of thin, flat scales.

Question 9

Refer to the figure.  The figure illustrates the vertebrate body plan.Which of the following is not a feature of all vertebrates?

Accepted Answer

While all vertebrates have a skull with a dorsal brain and spinal cord, an internal skeleton, internal organs suspended in a coelom, and a well-developed circulatory system with a ventral heart, not all vertebrates have jaws with teeth for processing food. For example, some species of lampreys and hagfish do not have true jaws or teeth.

Question 10

Which statement concerning lancelets (cephalochordates) is false?

Accepted Answer

Lancelets are filter feeders that rely on ciliary action to pump water through their pharyngeal slits to trap and filter microorganisms. They do not actively hunt and catch prey.

Question 11

Which group of organisms evolved with terrestrial limbs and digits (fingers and toes) in place of fins?

Accepted Answer

Amphibians were the first group of organisms to evolve limbs and digits specifically adapted for terrestrial locomotion, allowing them to move from aquatic to terrestrial environments. The development of these limbs from fins allowed for a more efficient way of moving on land and was a critical step in the evolution of vertebrates towards animals that could live and move about on land.

Question 12

Refer to the figure showing a Petromyzon marinus.  This lamprey shown obtains nutrients by

Accepted Answer

Lampreys, like Petromyzon marinus shown, are jawless organisms that attach to fish and rasps away the flesh with their sucker-like mouths to obtain nutrients.

Question 13

As deuterostomes, chordates possess pharyngeal slits at some stage of development.Which of the following chordates presents an example of why caution is needed when phylogenetic relationships are assessed using only adult structures?

Accepted Answer

Tunicates, which are adult chordates, lack many of the defining characteristics of chordates, such as a backbone and a centralized nervous system. However, their larval stage does possess pharyngeal slits, making them an important example of why relying solely on adult structures can lead to misleading phylogenetic relationships.

Question 14

Refer to the figure.  What modification in jaw structure occurred in early jawed fishes that was not found in jawless fishes at that time?

Accepted Answer

Jawed fishes evolved from jawless fishes by modifying their gill arches, which eventually developed into jaws. This modification allowed jawed fishes to become more efficient predators, and resulted in the diversification of jawed fish species.

Question 15

A group that is often considered among the vertebrates but is thought by some scientists to be a sister group to the vertebrates includes the _______, which produces large amounts of slime as a defense mechanism, has three small accessory hearts, and does not possess stomach or jaws.

Accepted Answer

The characteristics listed, such as large amounts of slime as a defense mechanism, three small accessory hearts, and the absence of stomach or jaws, all point towards the hagfish as the group being described. Lampreys are also considered a sister group to vertebrates, but they have a different set of characteristics such as a sucking mouth and the ability to parasitize other fish. The other choices - eel, slug, and salp - are not related to this group in any way.

Question 16

Frogs are unique among the vertebrates because they possess, at some stage of development,

Accepted Answer

Frogs are unique among vertebrates due to their short vertebral column and modified pelvic region, adaptations related to their jumping and swimming abilities. Other options like a notochord, dorsal hollow nerve cord, pharyngeal slits, and a post-anal tail are common features in the development of many vertebrates, not unique to frogs.

Question 17

Which of the following was an adaptation in lobe-finned vertebrates that was instrumental in the transition to life on land and therefore important in the evolution of the amphibians?

Accepted Answer

Jointed fins with strong muscular support allowed lobe-finned fishes to have greater control and flexibility in moving their fins, which is important for movement on land. This adaptation eventually led to the development of limbs in amphibians. Flattened scales, jaws with teeth, cartilage skeleton, and notochord are also important adaptations in vertebrates but not specifically related to the transition to life on land.

Question 18

Which group of organisms is associated with the evolutionary innovation of an operculum over the gill slits?

Accepted Answer

Ray-finned fishes are known to have evolved the operculum over the gill slits, which serves as a protective covering and helps in water circulation for respiration. This innovation has not been observed in any other group of organisms.

Question 19

_______ propel themselves by means of vertical undulating movements of their greatly enlarged pectoral fins.

Accepted Answer

Skates and rays are known to propel themselves by means of vertical undulating movements of their greatly enlarged pectoral fins. Sharks also have enlarged pectoral fins but they use them primarily for stabilizing rather than propulsion. Lampreys and hagfishes are not fishes and bony fishes use various methods of propulsion including oscillating the body and the tail.

Question 20

During the Devonian, the partly terrestrial _______ arose from an ancestor shared with lungfishes that had enlarged, muscular pectoral and pelvic fins, each jointed to the body by a single enlarged bone.

Accepted Answer

The features described (enlarged, muscular pectoral and pelvic fins jointed to the body by a single enlarged bone) are characteristic of the earliest amphibians, which emerged during the Devonian period. Coelacanths and hagfishes are both more closely related to jawed fishes than to tetrapods, and reptiles did not arise until much later. Chondrichthyans (cartilaginous fishes) also existed during the Devonian period, but did not develop the adaptations necessary for a terrestrial lifestyle.

Quiz 32: Deuterostome Animals