在二叠纪末期，地球上发生了一次大规模的生物灭绝事件，导致多数生物销声匿迹，只留下少量的低级生物。日前，法国研究人员发现，一种名为鹦鹉螺（又称菊石）的贝壳类软体动物不但逃过一劫，而且还以惊人的速度恢复了往日的生机。
据法国国家科研中心最新公报介绍，地球上曾经发生过几次大规模的物种灭绝，其中在距今约2.5亿年前的二叠纪与三叠纪交界期发生的大灭绝最为严重，它使得超过90%的物种消失。此前的研究认为，生物圈用了1000万到3000万年的时间才恢复了灭绝前的繁荣。
科研中心的古生物学家对大灭绝的“幸存者”之一——鹦鹉螺进行了研究。后者是一种带有贝壳的软体动物，其贝壳花纹呈螺旋状。他们发现，大灭绝后，这种生物仅用了100多万年的时间就恢复了生机，甚至比以前更加繁荣，当时已有860种鹦鹉螺分布在全球77个地区。
研究小组成员、里昂大学的吉勒·埃斯卡尔盖尔表示，鹦鹉螺的恢复几乎没有过渡期，这可能是因为海洋中还存留了一些植物和动物，能够为它的生长提供营养。他认为，鹦鹉螺的重生过程将帮助人们了解大灭绝后生物圈的恢复情况。
相关的研究成果已经发表在最新一期的美国《科学》杂志上。（生物谷Bioon.com）
生物谷推荐原始出处：
Science 28 August 2009:DOI: 10.1126/science.1178325
Flourishing After the End-Permian Mass Extinction
Charles R. Marshall1 and David K. Jacobs2
Two hundred and fifty-two million years ago, the Paleozoic Era came to a cataclysmic close with the end-Permian mass extinction, when as much as 85% of readily fossilizable marine species became extinct. It took 5 million years for the biosphere to begin to recover from the event. At least this has been the conventional view. However, on page 1118 of this issue, Brayard et al. (1) show that ceratitid ammonoids (see the figure, panel A) recovered much faster than did most other marine groups, attaining considerable diversity just 1 million years after the mass extinction. Moreover, these mollusks reached a peak in their diversity at the end of the Early Triassic, when the diversity and body size of most other groups (particularly bivalves and gastropods) was still depressed (2). What do these data tell us about the post-apocalyptic world of the Early Triassic, and about the cause of the end-Permian extinction event itself?
1 Department of Invertebrate Paleontology, Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA.
2 Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA.
