Reconstructing paleoecology for critical transitions in hominin evolution

重建古生态学以了解古人类进化的关键转变

• 批准号: 2051213
• 负责人: Yohannes Ambaye
• 金额: $ 31.1万
• 依托单位: Arizona State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-01 至 2025-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2051213&HistoricalAwards=false
• 关键词: Reconstructing; paleoecology; critical; transitions; hominin

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.

了解与古人类化石相关的古生态学可以增进对决定人类谱系进化的因素的了解。在这个多学科项目中，研究人员重建了从 3.5 至 330 万年前的沉积物中发现人类祖先化石的地区的古生态学。他们根据总面积达 3000 平方公里的三个地点的动物群进行了高分辨率的区域级分析，并重建了人属起源之前的古生态环境。该项目促进本科生和研究生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人们对科学和人类起源研究的兴趣，并强调跨学科科学和研究背后人员的多样性。该项目测试了与人属出现、南方古猿阿法种明显灭绝以及共存古人类物种的古生态环境相关的假设。进行实地考察以完善相关部分的地层学和年龄，并在地点之间进行高分辨率的动物比较。项目动物专家完善哺乳动物化石的分类，收集和分析埋藏学和古生态学数据，对古环境进行高分辨率、大范围的重建，并评估在人属出现和阿法种消失之前的生态系统变化。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。饮食是通过牙釉质同位素（δ13C 和 δ18O）特征、中观磨损和低牙指数来估计的。通过对应分析，将连续时间段和不同地点的动物群落与现代群落进行比较，研究小组估计了三个地点之间不同的生物和非生物因素，并探索这些模式如何与阿法种的消失和人属的出现相一致。此外，物种聚类分析用于检查出现的生物地理模式，考虑分类学起源，假设传播模式，并估计区域古生态模式。该奖项反映了 NSF 的法定使命，并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，被认为值得支持。