非生物灾变事件的生物圈效应群集消失与群集出现

通过分析地球历史上的非生物灾变事件和生物事件发现,群集出现常伴随着群集消失,这可见于显生宙许多纪间界线附近,那里往往存在着地球灾变的标志。如同群集消失多由地球灾变引起一样,地球灾变亦是群集出现的一个重要动因。在灾变期,地球表层一般可分为非灾变区、边缘灾变区和中心灾变区。非灾变区生物以背景消失和背景出现为主,中心灾变区一般以群集消失尤其是群集绝灭为主,而边缘灾变区则既有群集消失又有群集出现尤其是群集起源,是进化的活跃地区,且其进化可称为巨进化。

BIOTIC EFFECTS OFABIOTIC CATASTROPHES MASS DISAPPEARANCES AND MASS APPEA RANCES

Mass disappearances are frequently followed by mass appearances and both are usually seen on many Phanerozoic inter-Period boundaries, where signs of some global catastrophes of lithospheric, hydrospheric, atmospheric or even astrospheric origin exist. Just as it could give rise to mass disappearance, a catastrophic event of the earth is also a major dynamic cause for mass appearance. During a catastraphic event, the surface layer of the earth where organisms dwell can generally be divided into Central Catastrophic Province, Peripheral Catastrophic Province and Non-Catastrophic Province according to the different intensity of the event. As far as the biospheric effect of an event is concerned, the non-catastrophic province is predominated by background disappearance and appearance, the central catastrophic province by mass disappearance, particularly by mass extinction, and the peripheral catastrophic province not only by mass disappearance but also by mass appearance, particularly by mass origination. Therefore, the peripheral catastrophic province is an active evolutionary zone. And the evolution in this province can be refered to as megaloevolution in contrast to the macroevolution and microevolution in the stable or equilibrial setting.