Reconstructing paleoecology for critical transitions in hominin evolution

了解与古人类化石相关的古生态学可以促进对决定人类谱系进化的因素的认识。在这个多学科项目中，研究人员重建了350万至330万年前从沉积物中发现人类祖先化石的地区的古生态学。他们进行高分辨率，区域级分析的基础上的动物群组合从三个网站，有一个总面积为3000平方公里，并重建古生态环境之前的属人的起源。该项目促进了本科生和研究生的培训以及国际研究合作。与该项目相关的科学传播和K-12科学教育活动旨在提高对科学和人类起源研究的兴趣，并突出跨学科科学和研究背后的人的多样性。该项目测试了与人属的出现，南方古猿阿法种的明显灭绝以及共存的人类物种的古生态背景有关的假设。进行实地工作，以完善有关部分的地层和年龄，并在各地点之间进行高分辨率的动物群比较。项目动物群专家完善哺乳动物化石的分类，收集和分析埋藏和古生态数据，进行高分辨率，大规模的古环境重建，并评估在人属出现和A消失之前的生态系统变化。阿法西斯对于样本中的每个化石物种，估计体重，饮食和底物使用的功能特征。通过牙釉质同位素（δ 13 C和δ 18 O）特征、中齿和高齿指数来估计饮食。使用对应分析比较连续时间箱和现代群落的跨站点的动物群组合，该团队估计了三个站点之间不同的生物和非生物因素，并探索了这些模式如何与A的消失相一致。afarensis和Homo的出现。此外，物种聚类分析用于检查出现的地理模式，考虑分类起源，假设扩散模式，并估计区域paleoecological patterns.This奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

Understanding the paleoecology associated with hominin fossils can advance knowledge about the factors that determined the evolution of the human lineage. In this multidisciplinary project, the researchers reconstruct paleoecology for regions where human ancestor fossils have been recovered from sediments between 3.5 and 3.3 million years ago. They conduct high-resolution, regional-level analyses based on the faunal assemblages from three sites that have a combined area of 3000 square kilometers and reconstruct the paleoecological context immediately preceding the origin of the genus Homo. The project advances undergraduate and graduate training and international research collaborations. Science communication and K-12 science education activities related to the project are designed to increase interest in science and human origins studies and highlight interdisciplinary science and the diversity of people behind the research. This project tests hypotheses related to the emergence of Homo, the apparent extinction of Australopithecus afarensis, and the paleoecological context of co-existing hominin species. Fieldwork is conducted to refine the stratigraphy and age of relevant sections and conduct high-resolution faunal comparisons between sites. Project faunal experts refine the taxonomy of mammalian fossils, collect and analyze taphonomic and paleoecological data, conduct high-resolution, broad-scale reconstruction of paleoenvironment, and assess ecosystem changes prior to the appearance of Homo and disappearance of A. afarensis. For each fossil species in the sample, functional traits of body mass, diet and substrate use are estimated. Diet is estimated through enamel isotopic (δ13C and δ18O) signatures, mesowear and hypsodonty indices. Using correspondence analysis to compare faunal assemblages from the successive time bins and across sites with modern communities, the team estimates biotic and abiotic factors that differed among the three sites and explores how these patterns align with the disappearance of A. afarensis and the appearance of Homo. In addition, species cluster analyses are used to examine biogeographic patterns that emerge, consider taxonomic origins, hypothesize patterns of dispersal, and estimate regional paleoecological patterns.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.