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 ill Asia, dinosaur fossils are now being discovered on all seven con
Once found almost entirely in the western United States and ill Asia, dinosaur fossils are now being discovered on all seven con
admin
2009-02-10
27
问题
Once found almost entirely in the western United States and ill 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. 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 axial tomography ( CT or CAT) scans &long 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 tricera tops 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 Noah 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 cash’s two supercontinents m 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 Noah America and migrated to Asia rather than the reverse, paleontologists said. Doug Wolfe named the important new species of dinosaur Zuniceratops christopheri after his son.
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 "dine expressway". The trampled area was found during the summer of 1998 on Alaska’s Noah Slope near the Brooks Range.
The tom found 13 new track sites and made casts from the prints of five different types of dinosaurs. The rock in which the prints wore 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 Noah 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 over 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-foot ed) dinosaur that wall 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 cash.
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.
Newly-found fossilized tracks in Alaska proved that dinosaurs’ migration between Asia and North America took place ______.
选项
A、much earlier than experts previously thought
B、much later than experts previously thought
C、after Asia became an independent continent
D、sometime around 25 million years ago
答案
A
解析
第八段中的第二句The rock in which the prints were found dates to more than 100 million years ago,or a bout 25 million years older than the previously discovered signs of dinosaurs in the Arctic region表明在阿拉斯加发现的恐龙痕迹是一亿年以前的,而最后一句说该发现提供了重要的证据表明亚美大陆之间的恐龙迁移发生在 Cretace
转载请注明原文地址:https://jikaoti.com/ti/Oa5MFFFM
0
专业英语四级
相关试题推荐
Beyonddemographics,theUnitedStatesconfrontswitharangeofother【M1】______challenges.Globalizationisonthetopoftha
JeffPetersandAndyTuckercouldneverbetrusted.Oneday,thetwomendecidedtoopenamarriagebusinesstomakesomequick
Before1973,abortionwasillegalinAmericaunlessthewoman’shealthwasthreatened.InMarchof1970,JaneRoe,asinglewom
Before1973,abortionwasillegalinAmericaunlessthewoman’shealthwasthreatened.InMarchof1970,JaneRoe,asinglewom
Womenfromthemid-30stothemid-50sarelesslikelythanAmericansoverallbeveryhappy,andmanyarerackedbyworriesabout
Oneofthefirstthingsthatshouldstrikeanyhalfobservantparentisthespeedandapparentaccuracyinwhichachildproceed
PassageOneWhatdoes"themightydeep"inPara.9referto?
PassageFour(1)Thosesettingmigrationpolicyinrichcountriesfaceanalmostimpossibletask.Thedemandsofdemograph
Somepessimisticexpertsfeelthattheautomobileisboundtofallintodisuse,Theyseeadayinthenot.too-distantfuturewh
WhichofthefollowingisNOTanevidenceofsomepeople’scarelessnessindailycommunication?
随机试题
材料1某县是国家挟贫开发重点地区,近年来政府大力支持惠农产业,但因市场信息不对称、项目不符合当地实际等原因,农民实际收益有限,一些群众对政府的扶贫项目极其排斥。针对这种现状,当地政府改变扶贫策略,不再要求农民“认领”扶贫项目,不主动资助农民创业,而让其
A.煮剂B.煎剂C.煮散D.饮剂E.露剂将药物用一定的温度和加热时间煎煮所得的液体剂型是
女性,停经90天,近日阴道有少量不规则出血,小腹隐痛。妇科检查见子宫高达脐,未能及胎体。B型超声子宫腔内为落雪状图像。应考虑为下列哪项情况
下列选项中,生用解毒,截疟,润肠通便,制用补益精血的是
枣仁安神颗粒的功能是()
背景安装公司总承包了新建机械厂的通风与空调工程,总工期为6个月。主辅材料均由A机电公司供应。其中分部分项工程工程量清单计价合计为536万元;措施项目清单计价合计60万元;其他项目清单计价合计15万元。取费费率为:规费费率:4.85%;税率3.56
下列属于绍兴菜的有()。
电子反对抗是指防止敌方或己方的电子对抗措施影响己方的设备和人员作战效能所进行的各种活动,以防护己方的战争力不遭受其损害,主要措施包含电子反侦察、电子反干扰、抗反辐射摧毁、抗定向能致盲和抗计算机病毒传染。根据上述定义,下列选项不涉及电子反对抗的是:
Annais18andshewantstodocomputerstudiessothatshecanworkinanoffice.ShewouldliketostudyinLondonbutisworr
Peoplecanbeaddictedtodifferentthings—e.g.,alcohol,drugs,certainfoods,oreventelevision.Peoplewhohavesuchailad
最新回复
(
0
)