- 1、本文档共6页,可阅读全部内容。
- 2、有哪些信誉好的足球投注网站(book118)网站文档一经付费(服务费),不意味着购买了该文档的版权,仅供个人/单位学习、研究之用,不得用于商业用途,未经授权,严禁复制、发行、汇编、翻译或者网络传播等,侵权必究。
- 3、本站所有内容均由合作方或网友上传,本站不对文档的完整性、权威性及其观点立场正确性做任何保证或承诺!文档内容仅供研究参考,付费前请自行鉴别。如您付费,意味着您自己接受本站规则且自行承担风险,本站不退款、不进行额外附加服务;查看《如何避免下载的几个坑》。如果您已付费下载过本站文档,您可以点击 这里二次下载。
- 4、如文档侵犯商业秘密、侵犯著作权、侵犯人身权等,请点击“版权申诉”(推荐),也可以打举报电话:400-050-0827(电话支持时间:9:00-18:30)。
- 5、该文档为VIP文档,如果想要下载,成为VIP会员后,下载免费。
- 6、成为VIP后,下载本文档将扣除1次下载权益。下载后,不支持退款、换文档。如有疑问请联系我们。
- 7、成为VIP后,您将拥有八大权益,权益包括:VIP文档下载权益、阅读免打扰、文档格式转换、高级专利检索、专属身份标志、高级客服、多端互通、版权登记。
- 8、VIP文档为合作方或网友上传,每下载1次, 网站将根据用户上传文档的质量评分、类型等,对文档贡献者给予高额补贴、流量扶持。如果你也想贡献VIP文档。上传文档
查看更多
托福阅读自然科学类文章之The Origination of Birds-智课教育旗下智课教育
智 课 网 托 福 备 考 资 料
托福阅读自然科学类文章之The Origination of
Birds-智课教育旗下智课教育
自然学科是托福阅读文章题材中比较常见的类型,本文和大家分享
的是自然科学类文章汇总系列的内容,供考生参考使用,希望考生能够
认真备考,预祝考生能够考出好成绩。
自然学科是托福阅读文章题材中比较常见的类型,本系列为大家汇
总整理了多篇托福阅读自然科学类文章,大家在托福备考时可以有针对
性的进行复习,本篇为大家带来的是The Origination of
Birds,并附有相应的练习,希望大家都能顺利拿下托福阅读 高分。
The Origination of Birds
Keywords:pterosaurs, Birds, wing, flight, fossil
The first flying vertebrates were true reptiles in which one of
the fingers of the front limbs became very elongated, providing
support for a flap of stretched skin that served as a wing. These
were the pterosaurs, literally the winged lizards. The earliest
erosaurs arose near the end of the Triassic period of the
Mesozoic Era, some70 million years
before the first known fossils of true birds occur, and they
presumably dominated the skies until they were eventually
displaced by birds. Like the dinosaurs, some of the pterosaurs
became gigantic; the largest fossil discovered is of an individual
that had a wingspan of 50 feet or more, larger than many
airplanes. These flying reptiles had large, tooth-filled jaws, but
their bodies were small and probably without the necessary
powerful muscles for sustained wing movement. They must have
been expert gliders, not skillful fliers, relying on wind power for
their locomotion.
Birds, despite sharing common reptilian ancestors with
pterosaurs, evolved quite separately and have been much more
successful in their dominance of the air. They are an example of a
common theme in evolution, the more or less parallel
development of different types of body structure and function
for the same reasonin this case,for flight. Although the fossil
record, as always, is not complete enough to determine
definitively the evolutionary lineage of the birds or in as much
detail as one would like, it is better in this case than for many
other animal groups.
That is because of the unusual preservation in
您可能关注的文档
- 古希腊神话法文版.pdf
- 法语单词词根速记7.pdf
- 通过简单示例学习链接脚本基本语法.pdf
- 托福独立口语话题之电子书还是纸质书-智课教育旗下智课教育.pdf
- shell基本语法.pdf
- 对商务英语阅读教学的几点思考.pdf
- EasyLanguage基础语法.pdf
- 杜克大学研究生的托福成绩要求-智课教育旗下智课教育.pdf
- 第四章 函数的语法.pdf
- 佛蒙特大学2016年研究生托福成绩要求-智课教育旗下智课教育.pdf
- DB23_T 3866-2024冰上龙舟赛事组织服务规范.docx
- DB32 2163-2012 棉纱单位可比综合电耗限额及计算方法.docx
- DB32∕T 2429-2013 棉花田间生长发育观察记载规范.docx
- DB23_T 3820-2024 工业互联网综合平台数据质量管理规范.docx
- DB23_T 3474-2023非煤智慧矿山信息系统技术规范.docx
- DB3201_T 1106-2022 工程地质层划分技术规范.docx
- DB33T 2515-2022公共机构“零碳”管理与评价规范.docx
- DB3301_T 0415-2023 装修垃圾收运处置管理规范.docx
- DB3311/T 106―2019“丽水山居”民宿服务要求与评价规范.docx
- DB3201T 1127-2022 慈善捐赠受赠管理规范.docx
文档评论(0)