Doctoral Dissertation Improvement-Paleoecology of the Upper Laetolil Beds, Laetoli, Tanzania: Its Implications for Hominid Evolution

对过去生态系统或古生态系统结构的分析被认为是当代人类进化研究的重要组成部分。通过对生态学和进化转变之间关系的详细研究，有可能产生关于最终导致原始人(人类及其已灭绝的近亲)进化史上重大事件的因素的假说，包括物种形成、适应性转变和灭绝。此前，对坦桑尼亚重要的古人类化石遗址莱托利(Laetoli)(可追溯到350万至380万年前)的古生态解释表明，它要么是干旱到半干旱的草原，有成片的灌木丛和林地，要么是更茂密的森林栖息地。这个项目的目标是通过更彻底地记录拉托利的古生态环境来解决这个有争议的问题。这项研究将利用来自Laetoli的化石动物群的一系列数据，并将各种方法和技术应用于这些数据，如指示物种、生态地貌、生态结构和群落组成分析。该项目还将首次调查各个地层层位和不同亚区之间的细粒度生态差异。总体目标将是对拉托利的古生态进行更详细、更全面和更知情的评估。这将考虑到可获得的广泛的动物群证据、该遗址所代表的地理和时间复杂性，以及由割胶因素造成的限制。该项目的结果将使人们更好地了解早期原始人利用的栖息地类型，并导致对其栖息地偏好的更关键的评价。该项目最终将在开发更广泛的宏观进化模型方面提供重要的构建块，这些模型对于理解和解释塑造人类进化的背景至关重要。

The analysis of the structure of past ecosystems, or paleoecology, is regarded as an essential component of contemporary studies of human evolution. Through detailed investigations of the association between ecology and evolutionary transformation it is possible to generate hypotheses about the factors that ultimately contributed to major events in the evolutionary history of hominids (humans and their close extinct relatives), including speciation, adaptive shifts, and extinctions. Previously, interpretations of the paleoecology at the important fossil hominid site of Laetoli in Tanzania (dating to 3.5-3.8 million year ago) have suggested that it is either an arid to semi-arid grassland with patches of bush and woodland or a more heavily wooded habitat. The objective of this project is to resolve this contentious issue by more thoroughly documenting the paleoecological setting at Laetoli. This study will utilize a range of data from the fossil faunas from Laetoli, and will apply a variety of methods and techniques to these data, such as indicator species, ecomorphology, ecological structure and community composition analyses. The project will also investigate, for the first time, fine-grained ecological distinctions between individual stratigraphic horizons and different sub-localities. The overall goal will be to present a more detailed, more comprehensive, and more informed assessment of the paleoecology at Laetoli. This will take into account the broad spectrum of faunal evidence available, the geographical and temporal complexity represented at the site, and the limitations imposed by taphonomic factors. The results of this project will provide a better understanding of the types of habitats exploited by early hominids, and lead to a more critical appreciation of their habitat preferences. The project will ultimately provide an important building block in developing broader scale macroevolutionary models that are essential for understanding and interpreting the contexts that shaped human evolution.