周口店直立人3号与5号头骨形态特征对比及其演化速率所反映的群体隔离

德日进认为周口店直立人保持着形态上的稳定性；这种进化上的缓慢性表明周口店直立人进化过程中无论何时都未曾发生过外来移民的闯入,从而打乱、干扰或推进其进化过程.本项研究采用三维结构重叠和精确测量数据的方式对比了周口店第一地点晚期代表周口店直立人(ZKD)5号头骨相对于早期代表ZKD3的形态特征演化变化,并与南京直立人(NJ)1和2号头骨之间的差别进行了对比.结果表明,周口店晚期标本相对于早期标本来说,头骨尺寸在各个方向上都有所增加,但轮廓形状基本保持一致,与同期的南京古人类的相比,周口店直立人的演化速率显得很慢.这很可能是由于缺乏基因交流的缘故；周口店直立人群有可能是一个相对隔离的群体.本项研究支持德日进等关于周口店直立人群缺乏基因交流的观点.

Morphological Comparison of the ZKD 3 and 5 Skulls and the Probable Population Isolation as Reflected by Evolutionary Rates

In 1941,Pere Teilhard de Chardin emphasized the morphological stability of Homo erectus from Zhoukoudian throughout the 50 meters of sediments of Locality 1.He believed that not a single anatomical difference could be detected between the skull remains found at the very bottom of the deposit and those collected at the very top.This morphological stability was evidence of a slowness that characterized biological evolution whenever not obscured,disturbed or accelerated by the intrusive immigration of foreign elements.The present study employs both traditional metrics and recently developed 3D scanning techniques to explore the morphological variations of skulls between the probable first and last inhabitants,represented by ZKD 3 and 5.Also these variations are scaled by those between NJ 1 and 2 skulls,whose owners probably spent the same duration as ZKD 3 and 5.After comparison,the skull of the latest(or top) inhabitant at Zhoukoudian Locality 1 was found to have increased in every direction related to the earliest(or bottom) inhabitant,while the shape seems to be relatively stable though the hundreds of thousand years that passed in the interim.In the present study,evolutionary rates of Homo erectus from Zhoukoudian were determined using 11 cranial measurements.The results show that biological evolutionary rate is very slow,compared with that of hominid from Nanjing.The Homo erectus crania from Zhoukoudian may represent an isolated population,and as a result,lacked evidence of gene flow from outside populations.