GRE Reading Comprehension

For a period of more than two centuries paleontologists have been intrigued by the fossilized remains of pterosaurs, the first flying vertebartes. The issues, which puzzle them, are how these heavy creatures, having a wingspan of about 8-12 meters managed the various problems associated with powered flight and whether these creatures were reptiles or birds. p<>. Perhaps the least controversial assertion about the pterosaurs is that they were reptiles. Their skulls, pelvises, and hind feet are reptilian. The anatomy of their wings suggests that they did not evolve into the class of birds. In pterosaurs a greatly elongated fourth finger of each forelimb supported a winglike membrane. The other fingers were short and reptilian, with sharp claws. In birds the second finger is the principal strut of the wing, which consists primarily of feathers. If the pterosaurs walked on all fours, the three short fingers may have been employed for grasping. When a pterosaurs walked or remained stationary, the fourth finger, and with it the wing, could only urn upward in an extended inverted V- shape along each side of the animal’s body.

In resemblance they were extremely similar to both birds and bats, with regard to their overall body structure and proportion. This is hardly surprising as the design of any flying vertebrate is subject to aerodynamic constraints. Both the pterosaurs and the birds have hollow bones, a feature that represents a savings in weight. There is a difference, which is that the bones of the birds are more massively reinforced by internal struts.

Although scales typically cover reptiles, the pterosaurs probably had hairy coats. T.H. Huxley reasoned that flying vertebrates must have been warm-blooded because flying implies a high rate of metabolism, which in turn implies a high internal temperature. Huxley speculated that a coat of hair would insulate against loss of body heat and might streamline the body to reduce drag in flight. The recent discovery of a pterosaur specimen covered in long, dense, and relatively thick hair like fossil material was the first clear evidence that his reasoning was correct.

Some paleontologists are of the opinion that the pterosaurs jumped from s dropped from trees or perhaps rose into the light winds from the crests of waves in order to become airborne. Each theory has its associated difficulties. The first makes a wrong assumption that the pterosaurs hind feet resembled a bat’s and could serve as hooks by which the animal could hang in preparation for flight. The second hypothesis seems unlikely because large pterosaurs could not have landed in trees without damaging their wings. The third calls for high aces to channel updrafts. The pterosaurs would have been unable to control their flight once airborne as the wind from which such waves arose would have been too strong. As seen in the above passage scientists generally agree that:

The view that, the pterosaurs rose into light winds from the crest of the waves to become airborne, is viewed by the author as

As inferred from the passage, the skeleton of a pterosaur is distinguishable from that of a bird by the

According to the passage which of the following is a characteristic of the pterosaurs?

The organization of the last paragraph of the passage can best be described as:

Maps made by non-Native Americans to depict Native American land tenure, resources and population distributions appeared almost as early as Europeans’ first encounters with Native Americans and took many form: missionaries’ field sketches, explorers’ drawings, and surveyors’ maps, as well as maps rendered in connection with treaties involving land transfers. Most existing maps of Native American lands are reconstructions that are based largely on archaeology, oral reports, and evidence gathered from observers’ accounts in letter, diaries, and official reports; accordingly, the accuracy of these maps is especially dependent on the mapmakers’ own interpretive abilities.

Many existing maps also reflect the 150-year role of the Bureau of Indian Affairs (BIA) in administering tribal lands. Though these maps incorporate some information gleaned directly from Native Americans, rarely has Native American cartography contributed to this official record, which has been compiled, surveyed, and authenticated by non-Native American tribes and their migrations and cultural features, as well as territoriality and contemporary trust lands, reflects the origins of the data, the mixed purposes for which the maps have been prepared, and changes both I United States government policy and in non-Native Americans’ attitudes toward an understanding of Native Americans.Which of the following best describes the content of the passage?

The passage mentions each of the following as a factor affecting current maps of Native American lands EXCEPT

The passage suggests which of the following about most existing maps of Native American lands?