The Origin and Evolution of Vertebrates

Which of the following traits is shared by all vertebrates, at least in some developmental stages, except the lampreys? notochord vertebrae cartilaginous skeleton cranium (head) mouth with jaws Answer: E This question relates to Concept 34.1. Lampreys are jawless fishes, but they have the four other vertebrate features.

Which of the following traits is shared by all vertebrates, at least in some developmental stages, except the lampreys? notochord vertebrae cartilaginous skeleton cranium (head) mouth with jaws

When early systematists distinguished Chondrichthyes (cartilaginous fish) from Osteichthyes (bony fish), it was not clear exactly when bony skeletons first appeared in the vertebrates. Which of these suggests that a reduction of bone in Chondrichthyes is a derived condition that emerged after the origin of bony skeletons? All fish except Agnatha have jaws. Chondrichthyes and Osteichthyes have paired fins and lateral lines. Traces of bone tissue are found in living and fossil Chondrichthyes. The cartilage skeleton of Chondrichthyes is impregnated with calcium. Chondrichthyes do not have swim bladders, as do many Osteichthyes. Answer: C This question relates to Concept 34.3. Options A, B, and E are true but not informative about the phylogenetic relationship; option D is true but calcium deposits are not the same trait as bone. 4

When early systematists distinguished Chondrichthyes (cartilaginous fish) from Osteichthyes (bony fish), it was not clear exactly when bony skeletons first appeared in the vertebrates. Which of these suggests that a reduction of bone in Chondrichthyes is a derived condition that emerged after the origin of bony skeletons? All fish except Agnatha have jaws. Chondrichthyes and Osteichthyes have paired fins and lateral lines. Traces of bone tissue are found in living and fossil Chondrichthyes. The cartilage skeleton of Chondrichthyes is impregnated with calcium. Chondrichthyes do not have swim bladders, as do many Osteichthyes. 5

Which of these correctly describes phylogenetic relationships among birds, mammals, and reptiles? Birds share the closest common ancestor with dinosaurs. Reptiles and birds, but not mammals, are amniotes. Mammals evolved from therapsid reptiles after the fall of the dinosaurs. Birds and mammals are more closely related to each other than either group is to crocodilian reptiles. Among living species in the group we call reptiles, turtles and snakes are most closely related to each other. Answer: A This question relates to Concept 34.5. Mammals diverged from stem reptiles early in amniote evolution. Amniotes include reptiles, birds, and mammals. Options D and E do not correctly describe phylogenetic relationships within amniotes. 6

Which of these correctly describes phylogenetic relationships among birds, mammals, and reptiles? Birds share the closest common ancestor with dinosaurs. Reptiles and birds, but not mammals, are amniotes. Mammals evolved from therapsid reptiles after the fall of the dinosaurs. Birds and mammals are more closely related to each other than either group is to crocodilian reptiles. Among living species in the group we call reptiles, turtles and snakes are most closely related to each other. 7

Which of the following groups soon outcompeted amphibians on land due to their watertight skin and watertight eggs? birds mammals reptiles none of the above Answer: C Reptiles have dry, scaly, watertight skin and watertight eggs, which greatly reduced their dependence on water compared to amphibians. 8

Which of the following groups soon outcompeted amphibians on land due to their watertight skin and watertight eggs? birds mammals reptiles none of the above 9

Which of the following chordate groups has all four key chordate characteristics as an adult? lancelets tunicates frogs humans Answer: A Lancelets have a notochord, a dorsal nerve cord, pharyngeal slits, and a post-anal tail in their larval forms as well as adult forms. 10

Which of the following chordate groups has all four key chordate characteristics as an adult? lancelets tunicates frogs humans 11

Which of the following Osteichthyan structures allows bony fishes to control their buoyancy using gases from their blood? operculum lateral line system swim bladder cloaca Answer: C The swim bladder can be inflated or deflated to control the buoyancy of a fish. 12

Which of the following Osteichthyan structures allows bony fishes to control their buoyancy using gases from their blood? operculum lateral line system swim bladder cloaca 13

Early vertebrate fossils called Conodonts can be identified by all of the following features except: an internal skeleton composed of cartilage large eyes for locating prey barbed hooks at the anterior end of their mouths slender, jawless bodies an inner ear with two semicircular canals Answer: E 14

Early vertebrate fossils called Conodonts can be identified by all of the following features except: an internal skeleton composed of cartilage large eyes for locating prey barbed hooks at the anterior end of their mouths slender, jawless bodies an inner ear with two semicircular canals 15

One of the reasons that the catch of cod (Gadus morhua) in the northwest Atlantic plummeted to 5% of its historic maximum was: industrial scale fishing global cooling restrictions on cod fishery Chytrid fungal disease Answer: D 16

One of the reasons that the catch of cod (Gadus morhua) in the northwest Atlantic plummeted to 5% of its historic maximum was: industrial scale fishing global cooling restrictions on cod fishery Chytrid fungal disease 17

Which of the following statements is not correct about the lateral line system? It can be found in aquatic gnathostomes It is used in digestion Lateral line organs form a row along each side of the body Lateral line organs are sensitive to vibration Answer: B

Which of the following statements is not correct about the lateral line system? It can be found in aquatic gnathostomes It is used in digestion Lateral line organs form a row along each side of the body Lateral line organs are sensitive to vibration Answer: B

Archaeopteryx differed from modern birds in that it had feathered wings flew well at high speeds could not take off from a standing position had airfoil wings with contoured feathers Answer: C

Archaeopteryx differed from modern birds in that it had feathered wings flew well at high speeds could not take off from a standing position had airfoil wings with contoured feathers