Exam 34: The Origin and Evolution of Vertebrates

Unlike eutherians, both monotremes and marsupials

Birds are descended from species that laid eggs in water. It could be argued that embryos of birds still develop in water because ________.

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

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-metre-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 organism was found to have two lungs, but the left lung was much smaller than the right lung. Kelly added that the herpetology instructor had said that in most snakes, the same condition exists. If the size difference between the lungs in this organism is not a shared ancestral characteristic with its occurrence in snakes, then its existence in this organism is explained as which of the following?

If a tunicate's pharyngeal gill slits were suddenly blocked, the animal would have trouble ________.

Which of the following are the only extant animals that descended directly from dinosaurs?

Fossils of the earliest tetrapods should ________.

At one time, birds held the same taxonomic rank as Reptilia and Mammalia. Now, however, they are considered as part of the reptile clade. Without this change, ________.

Suppose, while out camping in the bush, you found a chordate with a long, slender, limbless body slithering across the ground near your tent. This critter could be ________.

Female birds lay their eggs, thereby facilitating flight by reducing weight. Which "strategy" seems most likely for female bats to use to achieve the same goal?

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 metre tall) with small braincases (approximately 380 cubic centimetres) 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. \begin{array}{|c|c|c|c|c|} \hline \text { Species } & \text { Location of Fossils } &\text{Estimated Average Braincase Volume \left(\mathrm{cm}^{3}\right) } &\text{Estimated Average Body Mass (kg)}&\text{Asso ciated with Stone Tools?}\\\hline\\\text { Australopitheaus } & \\\text { afarensis } & \text { Africa } &450&36&No\\\hline \text { A. africanus } & \text { Africa }&450&36&No \\\hline \text { Paranthropus boisei } & \text { Africa } &510&44&No?\\\hline \text { Homo habilis } & \text { Africa } &550&34&yes\\\hline \text { H. ergaster } & \text { Africa } &850&58&yes\\\hline \text { H. erectus } & \text { Africa, Asia } &1000&57&yes\\\hline \text { H. heidelbergensis } & \text { Africa, Europe } &1200&62&yes\\\hline & \text { Middle East, } \\\text { H. neanderthalensis } & \text { Europe, Asia } &1500&76&yes\\\hline \text { H. floresiensis } & \text { Asia } &380&16-36&yes\\\hline & \text { Middle East, } \\\text { H. sapiens } & \text { Europe, Asia }&1350&53&yes\\\hline\end{array} The table is a comparison of several characteristics of H. floresiensis to those of nine other hominin species (arranged roughly from oldest to most recent). What do these data suggest?

Which of the following characteristics allowed early gnathostomes to become successful predators?

Mammals and birds eat more often than reptiles. Which of the following traits shared by mammals and birds best explains this habit?

The history of hominin evolution demonstrates ________.

Many sentences in this chapter include the words "may suggest". This phrase indicates that ________.

It is believed that the coelacanths and lungfish represent a crucial link between other fishes and tetrapods. What is the major feature in these fish in support of this hypothesis?

Which of the following characteristics occur in Homo naledi?

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

Which of the following represents the strongest evidence that two of the three middle ear bones of mammals are homologous to certain reptilian jawbones?

A new species of aquatic chordate is discovered that closely resembles an ancient form. It has the following characteristics: external armour of bony plates, no paired lateral fins, and a suspension-feeding mode of nutrition. In addition to these, it will probably have which of the following characteristics?