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

人们早就知道，人体骨骼对体力活动的反应是，当一个人从事高水平的体力活动时，骨骼会变得更强壮，而当一个人不活动或不活动时，骨骼会变弱。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一生中参加的体育活动的数量。先前对过去人群的研究表明，不同人群的骨骼强度差异很大，因此，他们经常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近代人类相比，在农业之前从事狩猎和采集生活方式的人群的骨骼反映了一种非常活跃的生活方式。尼安德特人和最早的现代人类的腿骨和臂骨与最近的人群相比，显示出巨大的力量，这可能是一种体力要求高的生活方式和大量人口流动的结果。但是不同种群的长骨强度是如何产生差异的呢？在成年人群中看到的差异是否部分反映了成年前的活动？在生长过程中，种群间骨骼强度的差异是在什么时候出现的？所有种群是否都以同样的模式和速度获得骨骼强度？在美国国家科学基金会（National Science Foundation）的资助下，利比·考吉尔（Libby Cowgill）将通过分析大量近期人类儿童样本的长骨，并将其骨骼强度与尼安德特人和早期现代人类儿童样本进行比较，来研究这些问题。这个项目的数据将在美国、欧洲和非洲的博物馆收集，通过使用便携式x光机。一种叫做横截面几何的技术将被用来测量和量化每根骨的中轴水平的骨的数量和分布。通过检查800多名儿童的骨骼强度，将建立长骨强度发育变化的正常范围。一旦知道了这一点，就可以将尼安德特人和早期现代人类儿童的骨骼与近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为关于现代人类行为和生物学起源的持续争论提供线索。此外，这项研究将首次使用地理上不同的儿童样本对骨骼强度的生长变化进行分析。这些数据对医学界和临床研究都有潜在的价值，并最终增强我们目前对过去和现在生长和活动之间相互作用的理解。此外，这项研究是论文项目的一部分，通过提供继续从事人类学研究所需的研究技术和理论背景的坚实知识基础，将促进研究生的培训。

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.