新东方在线网络课堂 托福 新东方在线 > 托福 > 托福精选 > 正文

科学美国人60秒:古墨西哥人养兔子-托福听力下载

2016-11-18 15:55:37 来源:网络托福资料下载

点击查看>>科学美国人60秒音频:古墨西哥城市人热衷养兔子

  科学美国人60秒中英文翻译:古墨西哥城市人热衷养兔子

  科学美国人60秒英文文本

  This is Scientific American — 60-Second Science. I'm Cynthia Graber.

  As humans developed civilizations in Eurasia and Northern Africa, they also domesticated animals for food and labor: horses, cows, goats, pigs, sheep and a few others. But no evidence existed for the deliberate cultivation and breeding of animals in North or Central America—until now.

  "So at this ancient city of Teotihuacan in particular, which is really one of the earliest urban cities in North America..."

  Andrew Somerville of the University of California San Diego, talking about the metropolis that once existed some 30 miles northeast of present-day Mexico City.

  "...previous excavations have found a lot of rabbits. But at one compound in particular they found more evidence that they were interacting with rabbits more intensively. There was a statue of a rabbit. There was evidence that maybe they were butchering them. And this compound, which is called Oztoyahualco, actually had almost twice as many rabbit bones relative to the other complexes at the city. So it did seem like something was different with this particular compound."

  Somerville and colleagues tested 134 rabbit bones at the 2,000-year-old site, as well as 13 contemporary samples. If the ancient rabbits fed on wild vegetation, the carbon isotopes in the bones would show evidence of what's known as the C3 photosynthetic pathway. But the domesticated crops of that time, such as corn and cactus fruit, employ what's called the C4 pathway—which leaves a different carbon isotope ratio in the bones.

  兔子.jpg

  "Fortunately we were able to actually show that rabbits from this compound did actually have higher carbon values, significantly higher carbon values. Which means that they did have significantly different diets from other rabbits within the city, and also significantly different diets than wild rabbits from around the region. Which is pretty strong evidence we say to show that they were actually being provisioned by humans, fed by humans, managed by humans."

  The research is in the journal PLoS ONE.

  It's true that the carbon evidence could also be the result of the rabbits being trapped in corn fields, where they were scavenging. But the presence of the dedicated pen and the statue of a rabbit led the scientists to conclude that the animals were in fact being raised—which changes our understanding of New World cities.

  "That is one of these assumptions about the new world—that they just didn't have as intensive relationships with animals. That husbandry, especially with mammals, wasn't as important of a factor in their organization and supporting these big cities. So what we're showing is that maybe they were just as intensive in some respects as these old world cities but they're just less archaeologically visible. A rabbit leaves a much smaller footprint than a cow or a horse does."

  Thanks for listening for Scientific American — 60-Second Science Science. I'm Cynthia Graber.

  中文翻译请点击下一页

本文关键字: 科学美国人60秒 科学60秒下载 托福听力

为你特别匹配的托福超值课程,快速提分先人一步!
  • 【直播课程】托福考前10天,如何才能自救

    【直播课程】托福考前10天,如何才能自救

    适合人群:备战托福的筒子们!!!

    课时:8 课程有回放~

    查看详情
  • 大学生旗舰直达冲100分

    【知心托福】大学生旗舰直达冲100分

    适合人群:托福目标分数100!!!

    课程特色:推送补充相应知识点,有效提升学习效率。

    查看详情
  • 【21天冲分】 21天直冲托福100+

    【21天冲分】 托福2018年8月临考急训25人班

    适合人群:参加过托福考试或基础段的学习,距离最新考试仅剩1个月时间,急需短期内快速高效冲分的考生。

    特点:全科直播24小时

    查看详情
  • TOEFL8月早练团

    【早练团】TOEFL8月早练团

    课程特色:高能学习的正确打开方式,早练早提分!

    课时:28课时(每天0.5小时,5月共上课28天)

    查看详情
  • 大学生旗舰直达班 (冲110分)

    【知心托福】大学生旗舰直达班 (冲110分)

    适合人群:托福目标分数110分!

    课时:343

    查看详情

托福人气课程推荐全部课程

最受欢迎课程 知心托福大学生旗舰直达班(冲110分) ¥8280 免费试听
知心托福中学生旗舰直达班(冲110分) ¥8280 免费试听
知心托福精品直达班(冲110分) ¥5880 免费试听
单项突破 阅读口语听力写作
托福入门 词汇语音精听三科联报
直播课堂 考前预测
致赢一对一 临考冲刺临考强化短期集训强化冲分低起点冲分零起点托管冲分
更多托福课程
新东方23年教学经验沉淀
托福考生必修课
全球首发ETS独家授权TPO全真模考精准预测
查看详情

课程试听换一换

  • 知心托福 大学生旗舰直达班 (冲110分)

    ¥8280

  • 知心托福 直达班(冲110分)

    ¥4380

  • 知心托福 精品直达班(冲110分)

    ¥5880

  • 知心托福 直达班(冲100分)

    ¥4080

  • 知心托福 精品直达班(冲100分)

    ¥5680

  • 知心托福 大学生旗舰直达班 (冲100分)

    ¥7980

  • 新东方托福全名师21天魔鬼急训冲分【8月...

    ¥7499

  • 知心托福 中学生旗舰直达班 (冲110分)

    ¥8280

分享到:

相关推荐

交流 • 下载

精品课限量免费领

  • 托福名师直播公益课
  • 北美中学直播课程
  • 托福听力备考全攻略
  • 世界大学排名榜(全球大学排名)
  • 最新美国大学排名

提分历程更多>>

实用 • 工具

托福课程排行榜本周本月

托福公开课更多>>

新东方在线托福名师宣传片 w 03分32秒
1 新东方在线托福名师宣传片
新东方在线知心托福介绍说明【热】 w 04分14秒
2 新东方在线知心托福介绍说明【热】
新东方在线唐悦宁:托福词汇遗忘规律 w 07分34秒
3 新东方在线唐悦宁:托福词汇遗忘规律
新东方在线唐悦宁:词根词缀记忆法 w 04分42秒
4 新东方在线唐悦宁:词根词缀记忆法
新东方在线唐悦宁:托福听力基础预备 w 03分30秒
5 新东方在线唐悦宁:托福听力基础预备

推荐阅读