Exam 34: The Origin and Evolution of Vertebrates

Which of these statements accurately describes a similarity between sharks and ray-finned fishes?

Ancient fossils that seem to be an intermediate stage in the evolution from fish to tetrapods had which of the following characteristics?

Which of these would a paleontologist most likely do to determine if a fossil represents a reptile or a mammal?

In what respect do hominins differ from all other anthropoids?

All chordates studied to date, except tunicates, share a set of ________.

With which of the following statements would a biologist be most inclined to agree?

Which of these characteristics contributed the most to vertebrate success in relatively dry environments?

Marsupials survived in Australia (as opposed to Asia)because ________.

Unlike eutherians, both monotremes and marsupials ________.

Use the following information to answer the question. While on an intersession course in tropical ecology, Kris pulls a large, snakelike organism from a burrow (the class was granted a collecting permit). The 1-meter-long organism has smooth skin, which appears to be segmented. It has two tiny eyes that are hard to see because they seem to be covered by skin. Kris brings it back to the lab at the field station, where it is a source of puzzlement to the class. Kris says that it is a giant oligochaete worm; Shaun suggests it is a legless amphibian; Kelly proposes it belongs to a snake species that is purely fossorial (lives in a burrow). The class decided to humanely euthanize the organism and subsequently dissect it. Having decided that it was probably not a reptile, two of their original hypotheses regarding its identity remained. Which of the following, if observed, should help them arrive at a conclusive answer?

Which of the following could be considered the most recent common ancestor of living tetrapods?

A team of researchers has developed a poison that has proven effective against lamprey larvae in freshwater cultures. The poison is ingested and causes paralysis by detaching segmental muscles from the skeletal structures. The team wants to test the poison's effectiveness in streams flowing into Lake Michigan, but one critic worries about potential effects on lancelets, which are similar to lampreys in many ways. Why is this concern misplaced?

Vertebrates and tunicates share

During chordate evolution, what is the sequence (from earliest to most recent)in which the following structures arose?

Which of the following characteristics evolved independently in mammals and birds?

Which of these traits is most strongly associated with the adoption of bipedalism?

Which characteristic is common to all the modern representatives of all major reptilian lineages (turtles, lepidosaurs, crocodilians, and birds)?

Use the following information to answer the question. Brown et al. and Morwood et al. reported in 2004 that they had found skeletal remains of a previously unknown type of hominin, now dubbed Homo floresiensis, on the Indonesian island of Flores. These hominins were small (approximately 1 meter tall)with small braincases (approximately 380 cubic centimeters)as compared with other hominins. The remains of H. floresiensis were found alongside handmade stone tools and the remains of dwarf elephants that also inhabited the island, suggesting that H. floresiensis was able both to make tools and to coordinate the hunting of animals much larger than itself. H. floresiensis is estimated to have lived at the site where the remains were found from at least 38,000 years ago to 18,000 years ago. It is speculated that H. floresiensis and H. sapiens may have lived on Flores concurrently. Suppose researchers obtained mitochondrial DNA samples from the H. floresiensis remains, amplified a 1,000-base-pair sequence via PCR, and compared it to that of several currently living H. sapiens native to Indonesia, North Africa, and North America. Also suppose H. floresiensis were found to differ from the average Indonesian H. sapiens in 28 base pairs, from the average North African H. sapiens in 51 base pairs, and from the average North American H. sapiens in 53 base pairs, while two randomly selected H. sapiens differed from each other in an average of 21 base pairs. What would you surmise from these data?

Which of the following characteristics is shared by a hagfish and a lamprey?

What group of mammals have (a)embryos that spend more time feeding through the placenta than the mother's nipples, (b)young that feed on milk, and (c)a prolonged period of maternal care after leaving the placenta?