人类从哪里来?——(4)人类演化与古地理、古环境和古气候变化

Where are our humans from?——(4)Human evolution and paleogeographic,paleoenvironmental and paleoclimatic changes

详细介绍了8 Ma以来全球气候变化的规律,研究表明地球上主要发生过3次冷气候事件:第一次冷气候事件大约发生在距今7 Ma,一股强烈的干冷气流刮过欧洲大陆,穿越赤道地区直达非洲大陆,使得原始森林开始萎缩,面积的缩小导致古猿与人类发生演化分异;第二次冷气候事件大约发生在距今4.2 Ma,那时干冷气候持续发展,非洲大陆的原始森林进一步萎缩,并逐渐演化为稀树草原,出现了南方猿人和傍人;第三次冷气候事件大约发生在距今2.3 Ma,全球气候变化波动较大,冷-暖气候交替发育,地球上出现了真正意义上的人(人属),并逐渐演化成现代人。根据目前的研究,人类的起源和演化与古地理、古环境和古气候变化密切相关,人类演化历史大致可分为7个时期:撒海尔猿人—原初猿人时期、地居猿人时期、南方猿人—傍人时期、能人—鲁道夫人时期、匠人—直立人时期、先驱人—海德堡人时期和智人时期。

This paper makes an introduction to the regular pattern of global paleoclimatic change over the past 8 Ma in detail,showing 3 major cold climate events on the earth.The global climate was warm and humid during the period of 8-7 Ma,but a cold climate event(the first event)suddenly occurred about 7 Ma ago.Horribly strong cold and dry currents swept across Europe,across the equator,and into African continent,and then the primeval forests on the African continent were beginning to shrink,setting chimpanzees and human beings off on different evolutionary paths.The second cold climate event occurred about 4.2 Ma ago.Strong cold and dry currents continued to develop,and the primeval forests on the African continent shrank further into savanna,leading to the occurrence of Australopithecus and Paranthropus.The third cold climate event took place about 2.3 Ma ago.Since then the global climate fluctuated greatly,in which the cold and warm climates developed alternately.The human in the true sense(Genus Homo)first occurred on the earth,and then evolved gradually into H.sapiens including the modern humans.According to current research,the origin and evolution of humans are closely related to the changes of paleogeography,paleoenvironment and paleoclimate.The history of human evolution can be divided into 7 periods:the Sahelanthropus-Orrorin period,the Ardipithecus period,the Australopithecus-Paranthropus period,the Homo habilis-H.rudolfensis period,the H.ergaster-H.erectus period,the H.antecessor-H.heidelbergensis period and the H.sapiens period.