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可以促进对决定人类谱系进化的因素的了解。在这个多学科的项目中，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。他们根据三个总面积为3000平方公里的地点的动物群组合进行高分辨率的区域层面的分析，并重建紧挨着人属起源之前的古生态环境。该项目推进了本科生和研究生培训以及国际研究合作。与该项目有关的科学传播和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，并突出跨学科科学和研究背后的人的多样性。这个项目测试了与人的出现、非洲南方古猿的明显灭绝以及共存的人物种的古生态背景有关的假说。进行野外工作，以完善相关剖面的地层和年龄，并在不同地点之间进行高分辨率的动物群比较。动物群项目专家完善哺乳动物化石的分类，收集和分析墓葬和古生态数据，进行高分辨率、大范围的古环境重建，并在人的出现和阿法尔人消失之前评估生态系统的变化。对于样本中的每个化石物种，估计了体重、饮食和底物使用的功能特征。饮食是通过釉质同位素(δ13C和δ18O)信号、中耳指数和低牙指数来估计的。使用对应分析来比较来自连续时间仓和跨地点的动物组合与现代群落，研究小组估计了三个地点之间不同的生物和非生物因素，并探索了这些模式如何与阿法尔人的消失和人的出现相一致。此外，物种聚类分析被用来检查出现的生物地理模式，考虑分类起源，假设的扩散模式，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优势和更广泛的影响审查标准进行评估，被认为值得支持。