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学结构的分析，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调查，有可能产生关于最终促成原始人（人类及其已灭绝的近亲）进化史上重大事件的因素的假设，包括物种形成、适应性转变和灭绝。此前，对坦桑尼亚Laetoli重要的古人类化石遗址（距今350万至380万年前）的古生态的解释表明，它要么是一片干旱到半干旱的草地，点缀着灌木丛和林地，要么是一个树木繁茂的栖息地。该项目的目的是通过更全面地记录Laetoli的古生态环境来解决这一有争议的问题。本研究将利用来自Laetoli的化石动物群的大量数据，运用多种方法和技术对这些数据进行分析，如指示物种、生态形态、生态结构和群落组成分析。该项目还将首次调查个别地层层位和不同次地点之间的细粒度生态差异。总体目标将是对Laetoli的古生态进行更详细、更全面、更明智的评估。这将考虑到现有动物证据的广谱性、遗址所代表的地理和时间复杂性以及地理因素所施加的限制。该项目的结果将有助于更好地了解早期原始人所利用的栖息地类型，并对其栖息地偏好进行更批判性的评价。该项目最终将为开发更大规模的宏观进化模型提供重要的基石，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.