Doctoral Dissertation Research: Diet and Habitat of Australopithecus

在卡梅尔·施里雷博士的指导下，马特·斯彭海默先生将为他的博士论文收集数据。他的研究将是方法和实质性的，第一个方面是改进技术，以确定牙釉质中的土著碳同位素比率，第二个方面是重建史前饮食和环境。在广泛使用的人类学和生物学技术中，研究人员确定骨骼或牙齿中的碳12-13同位素比率，并使用这些数据重建动物饮食的各个方面。由于不同种类的植物遵循不同的光合作用途径，它们的碳同位素比率也不同，这种差异反映在吃这些植物的动物身上。通过对化石遗骸的分析，有可能深入了解饮食和环境。虽然这种技术产生了直观合理的结果，但许多方面需要改进。一个涉及成岩作用--化石材料在埋藏后的变化--在个别分析中，通常不确定所有测量到的碳是否都是在生物体死亡前结合的，或者一些碳是否来自周围的土壤。Sponheimer先生将进行实验来研究这个问题。他还将比较现代猪不同牙齿的同位素比率，以确定牙齿之间是否存在差异。 在研究的第二部分，Sponheimer先生将分析南非Makapansgat遗址的原始和非原始哺乳动物遗骸。这个洞穴填充物对古人类学家来说极其重要，因为富含化石的材料包含了大量的早期人类遗骸，这些遗骸被归类为南方古猿非洲种。 众所周知，南部非洲存在着几种原始人类，古人类学家希望了解每种原始人类所遵循的不同适应策略。虽然其中一种的同位素比数据是可用的，但还没有对A进行过研究。非洲人斯蓬海默先生收集的资料将引起许多古人类学家的兴趣。它将为早期人类的适应和他们居住的环境提供新的线索。该项目还将有助于培养一名有前途的青年科学家。

Under the direction of Dr. Carmel Schrire, Mr Matt Sponheimer will collect data for his doctoral dissertation. His research will be both methodological and substantive, the first aspect directed to improvement of the technique to determine indigenous carbon isotope ratios in tooth enamel and the second towards reconstructing prehistoric diet and environment. In a widely used anthropological and biological technique, researchers determine the carbon 12-13 isotopic ratio in bone or tooth and use these data to reconstruct aspects of an animal's diet. Because different categories of plants follow different photosynthetic pathways they vary in carbon isotope ratio and this differential is reflected in the animals which eat these plants. Through analysis of fossil remains it is possible to gain insight into both diet and environment. While this technique has produced intuitively reasonable results, a number of aspects require refinement. One involves diagenesis - alteration of fossil material after burial - and in individual analyses it is often uncertain whether all measured carbon was incorporated before the organism's death or whether some derives from surrounding soil. Mr. Sponheimer will conduct experiments to investigate this question. He will also compare isotope ratios from different teeth of modern day pigs fed controlled diets to determine whether between-tooth variation exists. In the second part of his study, Mr. Sponheimer will analyze both hominid and non-hominid mammalian remains from the South African site of Makapansgat. This cave infilling is extremely important to paleoanthropologists because the fossil-rich material contains abundant early hominid remains which are classed in the species Australopithecus africanus. It is known that several hominid species existed in southern Africa and paleoanthropologists wish to understand the different adaptational strategies followed by each. While isotope ratio data is available for one of these, no work has been done on A. africanus. The data which Mr. Sponheimer collects will be of interest to many paleoanthropologists. It will shed new light on early hominid adaptations and the environment which they inhabited. This project will also contribute to the training of a promising young scientist.