Collaborative Research: Filling in a temporal gap in hominin evolution

Ledi-Geraru研究项目（LRGP）通过探索埃塞俄比亚阿法尔的一个地区，促进了人类起源的科学研究，该地区含有300万至240万年前的罕见化石沉积物。在这一时期，人类谱系的行为和生物进化的证据是有限的。然而，这些沉积物包含了一些世界上最早的考古遗址，以及人类祖先的化石。将收集新的考古和古生物数据，为人类行为进化、南方古猿阿法种的灭绝、石器技术形式的物质文化起源以及古代哺乳动物物种的生物地理学提供更好的理解。研究人员将研究推动进化的各种因素，如气候变化，以了解人类进化史上生物和行为变化发生的条件。该项目将吸引K-12学生和广大公众；现场的即时发现将通过现场的互动博客实时发布，每位科学家在博客上与美国课堂上的学生互动。该项目还有助于培训来自美国和埃塞俄比亚的学生学习STEM科学。在这个为期三年的项目中，研究人员将收集考古、古生物学和古环境数据，以研究2.95-2.5 Ma时期人类谱系的行为和生物进化。在埃塞俄比亚阿瓦什河谷下游，阿法种猿人的最后出现时间为~2.95 Ma（哈达尔），其次是石器的出现时间为~2.58 Ma（戈纳）和能人（哈达尔）的出现时间为~2.35 Ma，这被描述为人类谱系的一次剧烈的生态位转移。该项目正在研究阿瓦什河谷下游迄今未记载的时期的地层。考古发掘工作正在以前发现过文物的地方扩大。研究人员将通过多种方法重建古人类的栖息地，包括哺乳动物群落结构、利用中穿和稳定同位素研究哺乳动物的饮食、生态形态学研究哺乳动物的运动模式以及植物遗骸分析。收集到的数据将与LGRP附近地区的古人类、动物和植物信息进行比较，这些信息涵盖了这段时间之前和之后的时间，以形成一个跨时间和空间的古环境和物种更替的区域代表。随后，这些数据将与阿瓦什下游地区以外的地点进行比较，以更好地了解东非的进化和生物地理模式。

The Ledi-Geraru Research Project (LRGP) promotes the science of human origins by exploring a region in the Afar of Ethiopia, which contains rare fossiliferous sediments ranging in time from 3.0-2.4 million years ago. The evidence for both behavioral and biological evolution in the hominin lineage is limited during this time period. However, these sediments contain some of the earliest archaeological sites in the world, as well as fossils of human ancestors. New archeological and paleontological data will be collected that provide a better understanding of hominin behavioral evolution, the extinction of Australopithecus afarensis, the origin of material culture in the form of stone tool technology, and the biogeography of ancient mammal species. The investigators will examine the various factors that are driving evolution, such as climate change, to understand the conditions under which biological and behavioral changes occurred in human evolutionary history. The project will engage both K-12 students and the public at large; the immediate field findings will be delivered in a real-time atmosphere through interactive blogs from the field in which each scientist interacts with students from U.S. classrooms. The project is also instrumental in training students from both the U.S. and Ethiopia in a STEM science. During this three-year project, the investigators will collect archaeological, paleontological, and paleoenvironmental data to address behavioral and biological evolution in the hominin lineage in the time period from 2.95-2.5 Ma. In the lower Awash valley of Ethiopia, the last appearance date of A. afarensis at ~2.95 Ma (Hadar), followed by the appearance of stone tools at ~2.58 Ma (Gona) and Homo cf. H. habilis (Hadar) at ~2.35 Ma, have been described as a drastic niche shift for the hominin lineage. This project is examining strata from a period heretofore undocumented in the lower Awash valley. Archaeological excavations are being expanded in locations where artifacts have been previously recovered. Past habitats in which hominins existed will be reconstructed with multiple methods including mammal community structure, utilizing mesowear and stable isotopes for mammalian diets, ecomorphology to retrodict mammal locomotor patterns, and analyses of botanical remains. Data recovered will be compared to hominin, faunal, and botanical information from localities near the LGRP that encompass time before and after this interval to develop a regional, representation of the paleoenvironment and species turnover across time and space. Subsequently, these data will be compared to sites beyond the lower Awash region to better understand East African evolutionary and biogeographical patterns.