首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Once found "almost entirely in the western United States and in Asia, dinosaur fossils are now being discovered on all seven con
Once found "almost entirely in the western United States and in Asia, dinosaur fossils are now being discovered on all seven con
admin
2012-04-23
59
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 Re had lips or that Triceratops had cheeks, says Lawrence Witmer, an assistant professor of anatomy at Ohio University in Athens, Ohio. Witmer was a leading researcher for a study on dinosaur anatomy that was presented at the annual meeting of the Society for Vertebrate Paleontology, which concluded on October 3 in Snowbird, Utah.
Witmer’s study reached its conclusions by using high - tech computerized aial 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 eight - year - old Christopher Wolfe and his father, paleontologist Doug Wolfe of the Mesa Southwest Museum in Arizona, date to about 90 million years ago. This could mean that ceratopsians originated in North America and migrated to Asia rather than the reverse, paleontologists said. Doug Wolfe named the important new species of dinosaur Zuniceratops Christopher after his son.
An expedition from the University 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 "dinosaur epressway". 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 dinosaur that was probably about 20m (about 70ft) 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.
Scientists speculated that the tracks were made at the edge of a lake or swamp and were then hardened and preserved. The rock containing the tracks was then pushed into a vertical position over millions of years of geologic activity. Dinosaur eggs have also been found at the site, which paleontologists are working to preserve before it falls victim to erosion. Paleontologists hope to study the site and learn about the diet and physical characteristics of the dinosaurs that are represented there.
The discovery of a new type of ceratopsian dinosaur suggests ceratopsians ______.
选项
A、migrated to North America around 70 - 80 million years ago
B、arrived in Asia from North America about 90 million years ago
C、originated in Asia and later migrated to North America
D、could have moved to Asia from North America long ago
答案
D
解析
A是科学家们以前的观点。原文中有This could mean that ceratopsians originated in North America and migrated to Asia rather than the reverse, paleontologists said.可知恐龙是由北美迁至亚洲的。可排除A和C。Doug Wolfe发现的化石可追溯到90000000年前。这个时间并非指迁徙时间,故B也不对。
转载请注明原文地址:https://kaotiyun.com/show/yHiO777K
0
专业英语八级
相关试题推荐
Americanschoolsaredividedinto______.
A、hewasfoundguiltyoftorturingCroatianprisoners.B、hewasinvolvedintheoperationtokill6people.C、hewasconvictedo
______gavethefamousspeechIhaveadream.
Manyparentsbelievethatearlychildhoodeducationisextremelyimportantforchildren’sdevelopment.Howfardoyouagreeor
Asoundcanchangebecauseoftheinfluenceofanadjacentsound.Thisisknownasassimilation.Whichofthefollowingwordsis
BecauseoftheWatergateScandal,President______resignedfromhisoffice.
ThepoeticstyleWaltWhitmandevisedisnowcalled______.
A、teachersarediscoveringforthemselveswhatchildrenandparentsneedB、thereissomeonetellingteachershowtoteachandwh
Accordingtothepassage,mostIcelandersviewlandassomethingof______.WhatisIceland’sold-agedadvocates’feelingtoward
随机试题
风险管理的过程主要包括()以及沟通和记录等。
培训
100mA电流属于()。
民用建筑的地下室内部标高低宇室外地坪的。必须设置污水排水设备的原因是()。
管理学上著名的马太效应来自一个故事:一个国王在远行前交给甲、乙、丙三个仆人每人一锭银子,并吩咐他们去做生意。国王回来时,奖励给甲10座城邑,因为他赚了10锭银子;奖励给乙5座城邑,因为他赚了5锭银子。等到听说丙将那锭银子包在手绢里一直没有拿出来时,国王怒不
在共同利益编织起的话语秩序下,商家们(),掺杂毒素,也成了“你知我知人不知”的圈钱()。即便有良心不安、道德自觉者,面对利益诱惑和行业规则,也()。
甲在油罐和货物混存的货场,用打火机烧开货物外包装袋,盗窃袋内物资,被盗物资遇明火燃烧,甲见状逃离,火势蔓延,造成了物资及附近建筑的巨大损失。甲的行为应认定为()(2016年法学基础课单选第2题)
Ittookdecadestoprovethatcigarettesmokingcausescancer,heartdisease,andearlydeath.Ittook【C1】______yearstoestabli
妈妈叫我去买东西了。
Anewstudyofthebrainishelpingscientistsbetterunderstandhowhumansprocesslanguage.Oneofthepatientsisawomanwit
最新回复
(
0
)