英语听力 学英语,练听力,上听力课堂! 注册 登录
> 在线听力 > 英语中级听力 > Breaking News 边听边练 2020 >  第96篇

BreakingNews·200712-Origin of our teeth dates back 400 million years

所属教程:Breaking News 边听边练 2020

浏览:

2021年07月25日

手机版
扫描二维码方便学习和分享
https://online2.tingclass.net/lesson/shi0529/10000/10339/200712.mp3
https://image.tingclass.net/statics/js/2012

Origin of our teeth dates back 400 million years

Researchers say they have discovered how humans got teeth. The researchers are from Uppsala University in Sweden. They say that human teeth "first evolved 400 million years ago". They believe our teeth came from an ancient fish called an acanthothoracid. The researchers studied a fossil of the fish. It was difficult to study because the fish is encased in rock. The researchers had to use the strongest X-ray machine in the world to analyse it. They used the X-ray machine to "digitally dissect" the fish. The researchers discovered that the fish's teeth were amazingly similar to human teeth. The researchers also said humans and 60,000 species of jawed vertebrates living on Earth today come from this fish.

The researchers say the acanthothoracid was one of the earliest jawed vertebrates with teeth ever to live. They were very excited at seeing how similar its teeth were to ours. A co-author of the study, Professor Per Ahlberg, said: "These findings change our whole understanding of the origin of teeth." He commented on the similarity to the fish, saying: "Their jawbones resemble those of bony fish and seem to be directly ancestral to our own. When you grin at the bathroom mirror in the morning, the teeth that grin back at you can trace their origins right back to the first jawed vertebrates." Another researcher said: "Nobody expected to find teeth so deep on the evolutionary tree."

用户搜索

疯狂英语 英语语法 新概念英语 走遍美国 四级听力 英语音标 英语入门 发音 美语 四级 新东方 七年级 赖世雄 zero是什么意思三明市泰元花园英语学习交流群

  • 频道推荐
  • |
  • 全站推荐
  • 推荐下载
  • 网站推荐