29.E: Vertebrates (Exercises)
29.1: Chordates
Review Questions
Which of the following is not contained in phylum Chordata?
- Cephalochordata
- Echinodermata
- Urochordata
- Vertebrata
- Answer
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B
Which group of invertebrates is most closely related to vertebrates?
- cephalochordates
- echinoderms
- arthropods
- urochordates
- Answer
-
A
Free Response
What are the characteristic features of the chordates?
- Answer
-
The characteristic features of the phylum Chordata are a notochord, a dorsal hollow nerve cord, pharyngeal slits, and a post-anal tail.
29.2: Fishes
Review Questions
Members of Chondrichthyes differ from members of Osteichthyes by having a ________.
- jaw
- bony skeleton
- cartilaginous skeleton
- two sets of paired fins
- Answer
-
C
Members of Chondrichthyes are thought to be descended from fishes that had ________.
- a cartilaginous skeleton
- a bony skeleton
- mucus glands
- slime glands
- Answer
-
B
Free Response
What can be inferred about the evolution of the cranium and vertebral column from examining hagfishes and lampreys?
- Answer
-
Comparison of hagfishes with lampreys shows that the cranium evolved first in early vertebrates, as it is seen in hagfishes, which evolved earlier than lampreys. This was followed by evolution of the vertebral column, a primitive form of which is seen in lampreys and not in hagfishes.
Why did gnathostomes replace most agnathans?
- Answer
-
Evolution of the jaw and paired fins permitted gnathostomes to diversify from the sedentary suspension feeding of agnathans to a mobile predatory lifestyle. The ability of gnathostomes to utilize new nutrient sources may be one reason why the gnathostomes replaced most agnathans.
29.3: Amphibians
Review Questions
Which of the following is not true of Acanthostega ?
- It was aquatic.
- It had gills.
- It had four limbs.
- It laid shelled eggs.
- Answer
-
D
Frogs belong to which order?
- Anura
- Urodela
- Caudata
- Apoda
- Answer
-
A
Free Response
Explain why frogs are restricted to a moist environment.
- Answer
-
A moist environment is required, as frog eggs lack a shell and dehydrate quickly in dry environments.
Describe the differences between the larval and adult stages of frogs.
- Answer
-
The larval stage of frogs is the tadpole, which is usually a filter-feeding herbivore. Tadpoles usually have gills, a lateral line system, long-finned tails, and lack limbs. In the adult form, the gills and lateral line system disappear, and four limbs develop. The jaws grow larger, suitable for carnivorous feeding, and the digestive system transforms into the typical short gut of a predator. An eardrum and air-breathing lungs also develop.
29.4: Reptiles
Review Questions
During the Mesozoic period, diapsids diverged into_______.
- pterosaurs and dinosaurs
- mammals and reptiles
- lepidosaurs and archosaurs
- Testudines and Sphenodontia
- Answer
-
C
Squamata includes_______.
- crocodiles and alligators
- turtles
- tuataras
- lizards and snakes
- Answer
-
D
Free Response
Describe the functions of the three extra-embryonic membranes present in amniotic eggs.
- Answer
-
The chorion facilitates the exchange of oxygen and carbon dioxide gases between the embryo and the surrounding air. The amnion protects the embryo from mechanical shock and prevents dehydration. The allantois stores nitrogenous wastes produced by the embryo and facilitates respiration.
What characteristics differentiate lizards and snakes?
- Answer
-
Lizards differ from snakes by having eyelids, external ears, and less kinematic skulls.
29.5: Birds
Review Questions
A bird or feathered dinosaur is ________.
- Neornithes
- Archaeopteryx
- Enantiornithes
- Paleognathae
- Answer
-
B
Which of the following feather types helps to reduce drag produced by wind resistance during flight?
- flight feathers
- primary feathers
- secondary feathers
- contour feathers
- Answer
-
D
Free Response
Explain why birds are thought to have evolved from theropod dinosaurs.
- Answer
-
This is suggested by similarities observed between theropod fossils and birds, specifically in the design of the hip and wrist bones, as well as the presence of a furcula, or wishbone, formed by the fusing of the clavicles.
Describe three skeletal adaptations that allow for flight in birds.
- Answer
-
The sternum of birds is larger than that of other vertebrates, which accommodates the force required for flapping. Another skeletal modification is the fusion of the clavicles, forming the furcula or wishbone. The furcula is flexible enough to bend during flapping and provides support to the shoulder girdle during flapping. Birds also have pneumatic bones that are hollow rather than filled with tissue.
29.6: Mammals
Review Questions
Eccrine glands produce ________.
- sweat
- lipids
- scents
- milk
- Answer
-
A
Monotremes include:
- kangaroos
- koalas
- bandicoots
- platypuses
- Answer
-
D
Free Response
Describe three unique features of the mammalian skeletal system.
- Answer
-
The lower jaw of mammals consists of only one bone, the dentary. The dentary bone joins the skull at the squamosal bone. Mammals have three bones of the middle ear. The adductor muscle that closes the jaw is composed of two muscles in mammals. Most mammals have heterodont teeth.
Describe three characteristics of the mammalian brain that differ from other vertebrates.
- Answer
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In some mammals, the cerebral cortex is highly folded, allowing for greater surface area than a smooth cortex. The optic lobes are divided into two parts in mammals. Eutherian mammals also possess a specialized structure that links the two cerebral hemispheres, called the corpus callosum.
29.7: The Evolution of Primates
Review Questions
Which of the following is not an anthropoid?
- lemurs
- monkeys
- apes
- humans
- Answer
-
A
Which of the following is part of a clade believed to have died out, leaving no descendants?
- Paranthropus robustus
- Australopithecus africanus
- Homo erectus
- Homo sapiens sapiens
- Answer
-
A
Free Response
How did archaic Homo sapiens differ from anatomically modern humans?
- Answer
-
Archaic Homo sapiens differed from modern humans by having a thick skull and a prominent brow ridge, and lacking a prominent chin.
Why is it so difficult to determine the sequence of hominin ancestors that have led to modern Homo sapiens ?
- Answer
-
The immediate ancestors of humans were Australopithecus . All people past and present, along with the australopithecines, are hominins. We share the adaptation of being habitually bipedal. The earliest australopithecines very likely did not evolve until 5 million years ago. The primate fossil record for this crucial transitional period leading to australopithecines is still sketchy and somewhat confusing. By about 2.5 million years ago, there were at least two evolutionary lines of hominins descended from early australopithecines.