Abstract: 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.

Key words: Homo erectus; Zhoukoudian; Evolutionary rate; Isolation