首页
登录
职称英语
Once found almost entirely in the western United States and in Asia, dinosaur
Once found almost entirely in the western United States and in Asia, dinosaur
游客
2023-12-16
20
管理
问题
Once found almost entirely in the western United States and in Asia, dinosaur fossils are now being discovered on all seven continents. A host of new revelations emerged in 1998 that promise to reshape scientists’ views of dinosaurs, including what they looked like and when and where they lived.
It is doubtful that Tyrannosaurus Rex had lips or that Triceratops had cheeks, says Lawrence Witmer, an assistant professor of anatomy at Ohio University in Athens, Ohio. He reached its conclusions by using high-tech computerized axial tomography (CT or CAT) scans along with comparative anatomy studies. For example, the theory that Triceratops and similar dinosaur species had cheeks was based on past comparisons with mammals such as sheep. But Witmer’s careful analysis found the structure of the triceratops jaw and skull made it more likely that Triceratops had a beak like that of an eagle. Witmer said that scientists should use birds and crocodiles as models when researching the appearance of dinosaurs.
In early October scientists announced that they had confirmed the discovery of a new type of ceratopsian dinosaur. The dinosaur’s bones, found in New Mexico in 1996, are forcing paleontologists to rethink their theories about when ceratopsians migrated to what is now North America.
Scientists previously thought that ceratopsians, the group that included the well-known Triceratops. arrived in North America from Asia between 70 million and 80 million years ago. During this time, the late Cretaceous Period. the earth’s two supercontinents—Laurasia in the north and Gondwanaland in the south—were in the process of pulling apart, cutting dinosaur populations off from each other and interrupting migratory patterns.
The fossilized bones, found by paleontologist Doug Wolfe of the Mesa Southwest Museum in Arizona, date to about 90 million yeses ago. This could mean that ceratopsians originated in North America and migrated to Asia rather than the reverse, paleontologists said.
An expedition from the Universities of Alaska in Anchorage and Fairbanks has discovered a region in remote northern Alaska so rich in fossilized dinosaur tracks that team members dubbed it the "dino expressway". The trampled area was found during the summer of 1998 on Alaska’s North Slope near the Brooks Range.
The team found 13 new track sites and made casts from the prints of five different types of dinosaurs. The rock in which the prints were found dates to more than 100 million years ago, or about 25 million years older than the previously discovered signs of dinosaurs in the Arctic region. Paleontologists said that the new findings provide important evidence that dinosaurs migrated between Asia and North America during the early and mid-Cretaceous Period. before Asia split off into its own continent.
Two rich fossil sites in the hills of Bolivia have been recently discovered, exciting paleontologists and dinosaur buffs. This discovery includes one of the most spectacular dinosaur trackways ever found.
The discovery of a large site in the mountain region of Kila Kila in southern Bolivia was announced in early October. Here scientists found the tracks of at least two unknown species of dinosaur. These included a large quadruped (four. footed) dinosaur that was probably about 20 m (about 70 ft) long.
The other site, located not far from the Bolivian city of Sucre, was uncovered in a cement quarry by workers several years ago but was not brought to paleontologists’ attention until the middle of 1998. The site features a vertical wall covered with thousands of dinosaur prints representing more than 100 different species. The tracks date back to between 65 million and 70 million years ago. Since dinosaurs are believed to have died out around 65 million years ago, the prints were likely made by some of the last dinosaurs on earth. Paleontologists hope to study the site and learn about the diet and physical characteristics of the dinosaurs that are represented there. [br] Witmer’s research leads people to believe ______.
选项
A、Tyrannosaurus Rex had lips and Triceratops had cheeks
B、dinosaurs might have looked tike mammals such as sheep
C、dinosaurs might not have looked like what we thought
D、dinosaurs must have looked like birds or crocodiles
答案
C
解析
根据第一段最后一句“new revelations ... to reshape scientist’s views of dinosaurs, including what they looked like...新的发现将改变科学家对恐龙长相的认识”即可基本判断C为答案,再结合第二、三段的主要内容可知, Witmer的研究表明恐龙的长相与过去科学家对恐龙长相的推测有很大差异,
转载请注明原文地址:https://tihaiku.com/zcyy/3279083.html
相关试题推荐
Artcanbemadeofalmostanything,includingsubstances
Artcanbemadeofalmostanything,includingsubstances
Artcanbemadeofalmostanything,includingsubstances
Artcanbemadeofalmostanything,includingsubstances
Artcanbemadeofalmostanything,includingsubstances
UntilJosquindesPrez,1440-1521,Westernmusicwasliturgical,designedas
UntilJosquindesPrez,1440-1521,Westernmusicwasliturgical,designedas
ThebeginningofwhatwastobecometheUnitedStateswascharacterizedbyin
ThebeginningofwhatwastobecometheUnitedStateswascharacterizedbyin
WhenthepresidentoftheUnitedStatesisimpeached______.A、theHouseofRepres
随机试题
[originaltext]M:Hello,Ruth.Nicetoseeyouagain.Youseemtobeverybusyr
一般情况下,最佳沥青用量OAC可以取()。A.OAC? B.OAC? C.
寒邪侵袭入里,与血相搏,血为寒凝,冲任阻滞,导致月经后期,量少,闭经,不孕等病,
B
资信评级机构向中国证监会备案,应当报送下列()材料。 ①证券评级机构备案表
A.消除副作用B.易于除去非药用部位C.降低毒性D.矫臭矫昧E.缓和药性骨碎补沙
不能作为糖异生的原料是A:乳酸 B:甘油 C:生糖氨基酸 D:乙酰辅酶A
企业民主管理制度的基本形式包括()。A:合理化建议 B:审核委员会 C
含氢氯噻嗪的中成药是A.珍菊降压片 B.维C银翘片 C.感冒清片 D.咳特
根据商业银行风险监管核心指标,我国商业银行收益合理性的监管指标有()。A.净
最新回复
(
0
)