Doctoral Dissertation Research: Ontogeny of Long Bone Diaphyses in Immature Late Pleistocene Humans

长期以来，人们一直认为，当一个人从事高水平的体育活动时，人的骨骼会变得更强壮，而当一个人保持不活动和静止时，人的骨骼就会变得更弱。体质人类学家在研究人类骨骼遗骸时，经常使用这一一般原则来推断特定人群在一生中参与的体力活动的数量。以前对过去人群的研究表明，不同的群体在骨骼强度上存在很大差异，因此，他们定期进行的体力活动也有很大差异。例如，与生活在城市环境中的新人群体不同，在农业之前参与狩猎和采集生活方式的个体群体具有反映非常活跃的生活方式的骨骼。与现代人类相比，尼安德特人和最早的现代人的腿骨和臂骨显示出巨大的力量，这可能是由于具有大量人口流动性的高体力生活方式的结果。但是不同的人群是如何在长骨强度上产生差异的呢？在成年人群中看到的差异在一定程度上反映了成年前的活动？在生长过程中，何时出现骨强度的种群差异，是否所有种群都以相同的模式和速度获得骨强度？在国家科学基金会提供的资金支持下，Libby Cowgill将通过分析大量近期人类儿童的长骨样本，并将他们的骨骼强度与尼安德特人和早期现代人类儿童的样本进行比较，来研究这些问题。这个项目的数据将通过使用便携式X光机在美国、欧洲和非洲的博物馆收集。一种被称为横截面几何学的技术将被用来测量和量化每根骨的中段水平的骨的数量和分布。通过对800多名儿童骨强度的检测，建立长骨强度发育变异的正常范围。一旦知道了这一点，尼安德特人和早期现代人类儿童的骨骼就可以与现代人类儿童的生长速度和模式进行比较。该项目提供的信息将阐明关于现代人类行为和生物学起源的持续辩论。此外，这项研究将首次使用不同地理位置的儿童样本对骨骼强度增长的差异进行分析。这些数据有可能对医学界和临床研究都有价值，并最终加强我们目前对过去和现在的增长和活动之间相互作用的理解。此外，这项研究是一个论文项目的一部分，该项目将通过提供研究技术和理论背景的坚实基础来促进研究生的培训，这些知识是继续人类学研究事业所必需的。

It has long been understood that human bone responds to physical activity by becoming stronger when an individual engages in high levels of physical activity, and weaker when an individual remains inactive and immobile. Physical anthropologists have often used this general principle when studying human skeletal remains to make inferences about the amount of physical activity a particular population was participating in during life. Previous studies of past populations have shown that different groups vary strongly in the strength of their bones, and hence, how much physical activity they were undertaking on a regular basis. For example, in contrast to populations of recent humans living in an urban environment, groups of individuals participating in a hunting and gathering lifestyle prior to agriculture have skeletons which reflect a very active lifestyle. The leg and arm bones of Neandertals and the earliest modern humans display great strength in contrast to more recent populations, which is likely a result of a physically demanding lifestyle with a large amount of populational mobility. But how do different populations come to vary in their degree of long bone strength? Are the differences seen in adult populations partially a reflection of activities prior to adulthood? When during growth do populational differences in bone strength emerge, and do all populations attain bone strength in the same pattern and at the same rate? With financial support supplied by the National Science Foundation, Libby Cowgill will examine these issues by analyzing the long bones of a large sample of recent human children and comparing their bone strength to a sample of Neandertal and early modern human children. Data for this project will be collected at museums in the United States, Europe, and Africa, through the use of a portable x-ray machine. A technique called cross-sectional geometry will be used to measure and quantify the amount and distribution of bone at the mid-shaft level of each bone. By examining the bone strength of over 800 children, the normal range of developmental variation for long bone strength will be established. Once this is known, the bones of Neandertal and early modern human children can be compared to the rate and pattern of growth in recent human children. Information provided by this project will shed light on the continuing debate regarding the origin of modern human behavior and biology. In addition, this research will provide the first analysis of variation in the growth of bone strength using a geographically diverse sample of children. This data has the potential to be of value to both the medical community and to clinical research, and ultimately enhance our current understanding of the interaction between growth and activity in both the past and present. In addition, this research is part of a dissertation project that will promote graduate student training by providing a solid basis of knowledge in the research techniques and theoretical background necessary for continuing a career in anthropological research.