32. Vertebrates

If an animal has segments, bilateral symmetry, pharyngeal clefts, a post-anal tail, and deuterostomic development, it must be a member of the __________.

A __________ is a chordate but not a vertebrate.

Which of the following chordate characteristics contributes most to the formation of your ears?

Which of the following chordate characteristics contributes most to suspension-feeding devices in many invertebrate chordates?

Which of the following pairs is not a correct match?

Which of the following can be found in vertebrates but not in lancelets and tunicates?

A lamprey, a shark, a lizard, and a rabbit share all the following characteristics except __________.

Which of the following is among the earliest known vertebrates?

The operculum was an important adaptation for fish because it helps with __________.

Some sharks are viviparous, which means that __________.

A feature of bony fish not found in sharks is __________.

Which of the following organisms is most closely related to the ancestor of modern amphibians?

Which of the following sets of animals contains only gnathostomes?

The first vertebrates to live on land were __________.

Which of the following animals is an amphibian?

Habitat loss, the spread of a fungal disease, climate change, and pollution are causing severe population declines and extinction in __________.

Vertebrates and tunicates share a. jaws adapted for feeding. b. a high degree of cephalization. c. an endoskeleton that includes a skull. d. a notochord and a dorsal, hollow nerve cord.

Living vertebrates can be divided into two major clades. Select the appropriate pair. a. the chordates and the tetrapods b. the urochordates and the cephalochordates c. the cyclostomes and the gnathostomes d. the marsupials and the eutherians

What trait(s) characterize the vertebrates? a. vertebrae and a cranium b. jaws and a spinal cord c. bony endoskeleton d. notochord and post-anal tail

"In the chordate phylogenetic tree below, fill in the shared derived character that defines each clade. a. Notochord b. Vertebral column c. Jaws d. Bony skeleton e. Four limbs f. Amniotic egg g. Hairs"

A lamprey, a shark, a lizard, and a rabbit share all the following characteristics except a. pharyngeal slits in the embryo or adult. b. vertebrae. c. hinged jaws. d. a dorsal, hollow nerve cord.

In Figure 34.25, which of the following is the sister taxon to the archosaurs? (A) synapsids (B) crocodilians (C) turtles (D) lepidosaurs

Which clade does not include humans? a. synapsids b. lobe-fins c. diapsids d. osteichthyans

Why were the Tiktaalik fossils an exciting discovery for scientists studying tetrapod evolution? a. They are the earliest frog-like animal discovered to date. b. They show that tetrapods successfully colonized land much earlier than previously thought. c. They have a roughly equal combination of fishlike and tetrapod-like characteristics. d. They demonstrate conclusively that limbs evolved as lobe-fins dragged themselves from pond to pond during droughts.

Which of the following could be considered the most recent common ancestor of living tetrapods? a. a sturdy-finned, shallow-water lobe-fin whose appendages had skeletal supports similar to those of terrestrial vertebrates b. an armored, jawed placoderm with two pairs of appendages c. an early ray-finned fish that developed bony skeletal supports in its paired fins d. a salamander that had legs supported by a bony skeleton but moved with the side-to-side bending typical of fishes

EVOLUTION CONNECTION Living members of a vertebrate lineage can be very different from early members of the lineage, and evolutionary reversals (character losses) are common. Give examples that illustrate these observations, and explain their evolutionary causes.

There is some evidence that pharyngeal slits occur in certain species of echinoderms that appear early in the fossil record. If confirmed, what do these data suggest? a. Echinoderms are chordates. b. Pharyngeal slits were present in the earliest echinoderms and lost later. c. Some lineages of echinoderms are more closely related to chordates than others. d. Pharyngeal slits should not be used as a trait in phylogenetic analysis.

There is some evidence that pharyngeal slits occur in certain species of echinoderms that appear early in the fossil record. If confirmed, what do these data suggest? a. Echinoderms are chordates. b. Pharyngeal slits were present in the earliest echinoderms and lost later. c. Some lineages of echinoderms are more closely related to chordates than others. d. Pharyngeal slits should not be used as a trait in phylogenetic analysis.

Compare the adaptations of amphibians and reptiles for terrestrial life.

As a genetic counselor, you advise couples about the possibility of genetic disease in their offspring. Today you met with an engaged couple, both of whom are phenotypically normal. The man, however, has a brother who died of Duchenne-type muscular dystrophy, an X-linked recessive condition. His fiancée, whose family has no history of the disease, is worried that the couple's sons or daughters might be afflicted. The sister of this man is planning to marry his fiancée's brother. How would you advise this second couple?

As a genetic counselor, you advise couples about the possibility of genetic disease in their offspring. Today you met with an engaged couple, both of whom are phenotypically normal. The man, however, has a brother who died of Duchenne-type muscular dystrophy, an X-linked recessive condition. His fiancée, whose family has no history of the disease, is worried that the couple's sons or daughters might be afflicted. How would you advise this couple?

Birds and mammals are both endothermic, and both have four-chambered hearts. Most reptiles are ectothermic and have three-chambered hearts. Why don't biologists group birds with mammals? Why do most biologists now consider birds to be reptiles?

Match each description on the left with the corresponding term on the right Closest relatives of chordates annelids nematodes sponges arthropods flatworms cnidarians molluscs echinoderms chordates

A good scientific hypothesis is based on existing evidence and leads to testable predictions. What hypothesis did the paleontologists who discovered Tiktaalik test? What evidence did they use to predict where they would find fossils of transitional forms?

Recall that hemophilia is an X-linked recessive disease. If a woman with hemophilia had children with a man without hemophilia, what is the chance that their first child will have the disease? What is the chance that their first child will be a carrier?

The size and shape of the vertebrate skull can reveal a great deal about an animal's lifestyle and evolutionary relationships. Consider your own skull. If you put your finger in your ear and move your jaw up and down, you can feel the space near the hinge of your jaw. Nestled in this space are the tiny bones that make your hearing possible: the malleus, incus, and stapes. All mammals have these three ear bones, but reptiles such as this T. rex don't. Where did ear bones come from?

A marine biologist has dredged up an unknown animal from the seafloor. Describe some of the characteristics that could be used to determine the animal phylum to which the creature should be assigned.