A cladogram shows that all chordates evolved from

1. A cladogram shows that all chordates evolved from • tunicates and lancelets. • dinosaur ancestors. • fishes. • a common ancestor.

2. Pikaia was an early • worm. • fish. • chordate. • lancelet.

3. A flexible, supporting structure found only in chordates is the • nerve net. • notochord. • pharyngeal slits. • dorsal fin.

4. Vertebrae are characteristic of • worms. • all chordates. • vertebrates only. • reptiles only.

5. Which of the following animals is NOT a nonvertebrate chordate? • Pikaia • worm • lancelet • tunicate

6. Which of the following pairs of modern chordate groups contains the most closely related groups? • hagfishes and lungfishes • lampreys and ray-finned fishes • birds and crocodilians • sharks and the coelacanth

7. Convergent evolution is the process that produces • species that are similar in appearance and behavior but not closely related. • unrelated species that are different in appearance and behavior. • closely related species that are similar in appearance and behavior. • closely related species that are different in appearance and behavior.

8. The sugar glider is an Australian marsupial. The eastern flying squirrel is a North American placental mammal. Both animals are nocturnal, live in trees, and can glide through the air using a flap of skin that stretches between the legs on each side of the body. The resemblance between these two animals is an example of • oviparous development. • ectothermy. • chordate diversity. • convergent evolution.

9. A rapid growth in the diversity of a group of organisms as they adapt to new conditions is called a(an) • cladogram. • ecological condition. • adaptive radiation. • evolutionary history.

10. The largest living group of chordates is the • amphibians. • fishes. • mammals. • birds.

11. Compared with the number of extinct chordate species, the number of living chordate species is • much larger. • slightly larger. • the same. • much smaller.

12. Essential life functions are carried out most efficiently when an animal’s internal body temperature is • insulated. • regulated by the environment. • the same as its external temperature. • within a particular “operating range.”

13. In vertebrates, each of the following is important in regulating body temperature EXCEPT a • source of heat. • way of conserving heat. • long digestive tract. • method of eliminating heat.

14. Suppose a terrestrial vertebrate has an optimal body temperature of 37°C but lives in an environment where the air temperature is 40°C. Which of the following is the most important requirement for that vertebrate to control its body temperature? • conserving body heat • eliminating excess body heat • maintaining a high, steady production of body heat • absorbing heat easily from its environment

15. Which of the following help mammals retain body heat? • hair and sweat glands • hair and body fat • bones and sweat glands • bones and body fat

16. Panting is a behavior that is seen most often in • endotherms that need to cool down. • endotherms that need to warm up. • ectotherms that need to warm up. • ectotherms that are at their ideal body temperature.

17. If each of the following vertebrates had a body temperature of 37°C and was placed in a cage where the air temperature was 30°C, which vertebrate would have the lowest rate of heat exchange with the air? • a hamster • a lizard • a frog • a snake

18. The main difference between ectotherms and endotherms is • the source of their body heat. • how they obtain food to provide for their metabolism. • whether they control their body temperature. • whether they conserve or eliminate body heat.

19. Filter feeders include all of the following EXCEPT • lancelets. • flamingoes. • crocodiles. • baleen whales.

20. Raccoons are omnivores, which means that they eat both meat and plant material. If you compared the digestive tract of a raccoon with that of a similar-sized herbivore and a similar-sized carnivore, the raccoon’s digestive tract would most likely • be the shortest of the three. • be the longest of the three. • have a length intermediate between the herbivore and the carnivore. • be the same length as the other two.

21. Colonies of bacteria in the intestines of a cow are helpful in • digesting cellulose fibers. • producing enzymes that digest meat. • straining plankton from water. • tearing and slicing food.

22. Which of the following vertebrates has a heart with four chambers? • a salamander • a lizard • a goldfish • a cow

23. What is the general rule regarding respiratory organs in chordates? • Aquatic chordates use lungs, and land vertebrates use gills. • Aquatic chordates use lungs and gills, and land vertebrates use gills. • Aquatic chordates use gills, and land vertebrates use lungs. • Aquatic chordates use gills, and land vertebrates use lungs and gills.

24. Chordate respiratory structures include all of the following EXCEPT • simple air sacs. • the medulla oblongata. • the surface of the skin. • the lining of the mouth.

25. When a fish respires, water flows in through which of the following patterns? • in through the gill slits, over the gill filaments, and out through the mouth • in through the gill filaments, over the gill slits, and out through the mouth • in through the mouth, over the gill slits, and out through the gill filaments • in through the mouth, over the gill filaments, and out through the gill slits

26. Which of the following happens in the alveoli? • Oxygen diffuses into the blood, and carbon dioxide diffuses into the air. • Carbon dioxide diffuses into the blood, and oxygen diffuses into the air. • Both oxygen and carbon dioxide diffuse into the blood. • Both oxygen and carbon dioxide diffuse into the air.

27. The main difference between an amphibian lung and a reptilian lung is that • an amphibian lung has a greater surface area for gas exchange. • a reptilian lung has a greater surface area for gas exchange. • an amphibian lung contains thousands of alveoli, but a reptilian lung does not. • a reptilian lung is connected to air sacs, but an amphibian lung is not.

28. The most efficient vertebrate lungs are found in • amphibians. • reptiles. • birds. • mammals.

29. Adult frogs breathe by using all of the following EXCEPT • their gills. • their moist skin. • their lungs. • the lining of their mouth and pharynx.

30. In a single-loop circulatory system, the atrium • receives the blood from the body. • pumps blood to the gills. • pumps blood to the lungs. • pumps blood throughout the entire body.

31. A single-loop circulatory system is characteristic of • fishes. • amphibians. • most reptiles. • crocodilians.

32. If a vertebrate has a circulatory system that carries oxygen-rich blood directly from the heart to the muscles, that vertebrate could be a • bony fish. • cartilaginous fish. • larval amphibian. • mammal.

33. The heart of a fish has • one atrium and one ventricle. • one atrium and two ventricles. • two atria and one ventricle. • two atria and two ventricles.

34. Ammonia is excreted by all of the following EXCEPT • larval amphibians. • tunicates. • most reptiles. • most fishes.

35. Animal X excretes nitrogenous wastes as uric acid and has a well-developed cerebrum. Animal X is a • cartilaginous fish. • crocodilian. • mammal. • bird.

36. In tunicates, some nitrogenous wastes leave the body in the form of • urea. • ammonia. • uric acid. • protein.

37. Suppose a mammal is born with a defect in its medulla oblongata. Which of the following functions is most likely to be affected? • ability to detect odors • ability to analyze objects by sight • control of the lungs, heart, or digestive tract • conscious thought

38. The simplest chordates that have cephalization as adults are • lancelets. • fishes. • amphibians. • reptiles.

39. All chordates have • a bony skeleton. • pharyngeal pouches. • a backbone. • fin girdles or limb girdles.

40. When a fish swims by bending its body and tail from side to side, the swimming movement is produced mainly by the contraction of muscles located in • limbs that stick out sideways from the body. • limbs that are attached straight under the body. • a siphon through which water leaves the body. • blocks on either side of the backbone.

41. A function of ligaments in a backbone is to • generate forward thrust during swimming. • keep the backbone straight and rigid. • connect the vertebrae. • make the body bend back and forth.

42. The sets of bones that support the limbs of vertebrates are called • opercula. • limb girdles. • ligaments. • vertebrae.

43. Sexual reproduction occurs in • fishes. • amphibians. • mammals. • all of the above

44. Embryos obtain nutrients from the yolk inside the egg in • oviparous and ovoviviparous animals. • viviparous and ovoviviparous animals. • viviparous and oviparous animals. • viviparous animals only.

45. Reproduction in most mammals involves • internal fertilization and ovoviviparous development. • internal fertilization and viviparous development. • external fertilization and oviparous development. • external fertilization and either oviparous or ovoviviparous development.

46. The notochord is a supporting structure that is found only in chordates. _________________________ • True • False

47. The simplest living animals to have all four chordate characteristics are the larvae of frogs. _________________________ • True • False

48. In a cladogram of modern chordates, endothermy is the adaptation that separates reptiles, birds, and mammals from other chordate groups. _________________________ • True • False

49. The ability of birds and bats to fly is an example of convergent evolution. _________________________ • True • False

50. More than 90 percent of all chordates living today are vertebrates. _________________________ • True • False