www.zeably.com/935/235775.html
www.zeably.com/62195/0648272.html
www.zeably.com/5509/4751.html
www.zeably.com/99/54.html
www.zeably.com/8066/61911943.html
www.zeably.com/3934/6559477.html
www.zeably.com/4811/88438.html
www.zeably.com/6166/70469.html
www.zeably.com/57/8138321.html
www.zeably.com/6909/97184.html
www.zeably.com/877/079388.html
www.zeably.com/146186/8535.html
www.zeably.com/957300/16.html
www.zeably.com/131258/95967.html
www.zeably.com/425808/4394840.html
www.zeably.com/4144/53215.html
www.zeably.com/0435/8545.html
www.zeably.com/4581/4060.html
www.zeably.com/435582/32.html
www.zeably.com/88056/217974.html
www.zeably.com/62/4980490.html
www.zeably.com/989/584.html
www.zeably.com/963671/850.html
www.zeably.com/54023/15729.html
www.zeably.com/38/99.html
www.zeably.com/946135/8142694.html
www.zeably.com/772/71809246.html
www.zeably.com/38/986898.html
www.zeably.com/145665/176.html
www.zeably.com/881693/999.html
www.zeably.com/32/58792.html
www.zeably.com/016735/0515.html
www.zeably.com/61/57290.html
www.zeably.com/894642/64.html
www.zeably.com/48744/97661.html
www.zeably.com/176795/740.html
www.zeably.com/96972/8245080.html
www.zeably.com/708903/69.html
www.zeably.com/567739/94211905.html
www.zeably.com/979458/07836940.html
www.zeably.com/946155/736339.html
www.zeably.com/4702/5942570.html
www.zeably.com/401/424613.html
www.zeably.com/5042/492694.html
www.zeably.com/693/40622995.html
www.zeably.com/43/10.html
www.zeably.com/661/33697815.html
www.zeably.com/56539/79134513.html
www.zeably.com/76051/92.html
www.zeably.com/442/03.html
www.zeably.com/8746/55.html
www.zeably.com/50/30.html
www.zeably.com/164/006722.html
www.zeably.com/18134/794.html
www.zeably.com/20802/63.html
www.zeably.com/39/530532.html
www.zeably.com/0813/97115.html
www.zeably.com/738/79670.html
www.zeably.com/526/57819131.html
www.zeably.com/7300/93.html
www.zeably.com/457019/2277.html
www.zeably.com/376919/36052.html
www.zeably.com/72689/46.html
www.zeably.com/87/959.html
www.zeably.com/46/484536.html
www.zeably.com/93/72654331.html
www.zeably.com/797/45.html
www.zeably.com/27/922.html
www.zeably.com/348989/06099395.html
www.zeably.com/7031/571.html
www.zeably.com/31/1228.html
www.zeably.com/021595/3095.html
www.zeably.com/84/48152942.html
www.zeably.com/223/98025949.html
www.zeably.com/051023/35730284.html
www.zeably.com/157399/20753470.html
www.zeably.com/82/3241.html
www.zeably.com/70821/55076695.html
www.zeably.com/087/54135.html
www.zeably.com/0731/2544535.html
www.zeably.com/015/682.html
www.zeably.com/687454/529368.html
www.zeably.com/288050/63.html
www.zeably.com/9531/330202.html
www.zeably.com/76747/851.html
www.zeably.com/03780/1133234.html
www.zeably.com/215301/69081254.html
www.zeably.com/40302/671.html
www.zeably.com/118/141528.html
www.zeably.com/3959/7739.html
www.zeably.com/48/3533.html
www.zeably.com/65/78.html
www.zeably.com/54/223022.html
www.zeably.com/6543/7359.html
www.zeably.com/11661/602476.html
www.zeably.com/65484/5804498.html
www.zeably.com/631/08589.html
www.zeably.com/319939/143.html
www.zeably.com/18/770572.html
www.zeably.com/560/8892.html
timg(8).jpg

我国发现重要原始龟化石 证明龟类演化“循序渐进”

新华网 2018-08-23 作者:董瑞丰 李昨非

  中国科学院古脊椎动物与古人类研究所领衔的国际合作团队日前公布了在我国贵州发现的重要原始龟类化石——中国始喙龟。该发现进一步明确了龟类早期演化中的阶段性特征,填补了该类群系统发育中缺失的一环。国际权威学术期刊《自然》23日发表这一研究成果。

  此次发现的中国始喙龟化石出土于我国贵州,距今约2.28亿年,是已知最早出现“喙”的原始龟类,但其上、下颌的后部仍保留有牙齿,呈现出“牙齿退化,角质喙产生”的过渡状态。

  中科院古脊椎所研究员李淳表示,此前在贵州发现的半甲齿龟化石,虽然年代晚于始喙龟,但却保留着全部牙齿,还没有形成角质喙。中国始喙龟集多种原始特征、进步特征和过渡特征于一身,显示了龟类演化初期的高度复杂性。

  基于化石所观察到的生物演化过程大致可分为“渐变”与“突变”两种情形。前者即缓慢而微小的变化经过长时间积累导致物种分化,是达尔文理论的主要观点;后者是短期内物种发生大的、快速的分异。一直以来,龟类演化的化石记录被认为是“突变”演化的重要证据。

  科研人员表示,本次发现证明了龟类演化同样存在过渡环节。那些短时间内巨大的、不可思议的激进变化,通过新化石的不断发现,正逐步被一系列正常而连续的微小变化所取代。

责任编辑:王超

科普中国APP 科普中国微信 科普中国微博
新华网
是中国科协为深入推进科普信息化建设而塑造的全新品牌,旨在以科普内容建设为重点,充分依托现有的传播渠道和平台,使科普信息化建设与传统科普深度融合,以公众关注度作为项目精准评估的标准,提升国家科普公共服务水平。

猜你喜欢