Department of Organismic and Evolutionary Biology, Harvard University, Herbaria, Cambridge, MA 02138, USA.
Curr Biol. 2011 Dec 20;21(24):R995-8. doi: 10.1016/j.cub.2011.11.020.
Living gymnosperms represent the survivors of ancient seed plant lineages whose fossil record reaches back 270 million years. Two recent studies find that recent pulses of extinction and speciation have shaped today's gymnosperm diversity, contradicting the widespread assumption that gymnosperms have remained largely unchanged for tens of millions of years.
活化石裸子植物代表了古老种子植物谱系的幸存者，其化石记录可以追溯到 2.7 亿年前。最近的两项研究发现，最近的灭绝和物种形成脉冲塑造了今天的裸子植物多样性，这与广泛认为裸子植物在数千万年中基本保持不变的假设相矛盾。
