Doctoral Dissertation Improvement Grant: Ecological niche evolution of Homo and Paranthropus at East Turkana, northern Kenya

全面了解一个物种的进化史包括确定驱动其适应的生态因素。所有物种都占据一个特定的生态位，其宽度由非生物（如气候和扩散障碍）和生物（如竞争）影响的相互作用决定。随着时间的推移，物种的生态位很少是静态的，不可避免的变化会导致各种各样的结果，包括进一步的适应、物种形成和灭绝。尽管历史上很难重建化石分类群的生态位，但最近发展起来的古生态学技术意味着，现在有可能检验关于生态学在两个重要的早期人类谱系的独立进化历史中可能发挥的作用的假设。确定我们的早期人类祖先如何与他们的环境相互作用是理解人类进化史的基础。化石记录表明，我们的属，人属，大约在240万年前起源于非洲东部，并与一种密切相关的物种——波伊塞傍人（Paranthropus boisei）共享环境。然而，该记录也表明，大约在1.3万年，傍人谱系灭绝，人属将其地理范围扩展到非洲以外。虽然这些谱系在时间上共存，但我们缺乏一个逻辑框架来测试与这一时期的生态有关的假设。该论文项目由博士生David Patterson（在乔治华盛顿大学ren<s:1> Bobe博士的指导下）通过使用新颖的方法来生成这两个谱系的生态位的第一个高分辨率重建，将有助于解决我们知识中的这些空白。本项目将哺乳动物群落生态学的定量方法与稳定同位素地球化学方法相结合，在空间受限的古代生态系统中研究人与傍人的生态位。拟议的研究将使用直接从这些古人类化石出现的地方收集的古生态数据，以及从肯尼亚北部Koobi Fora组大约2.0至1.4 Ma的考古遗址中收集的数据。通过集中研究同一地区的特定化石组合，本研究将为这两个谱系的生态位提供新的见解。这项研究的影响将通过共同pi参与国家自然历史博物馆（NMNH）的陆地生态系统进化（ETE）计划和Koobi Fora野外学校（KFFS）而扩大。作为项目评估的一部分，联合项目负责人将通过赞助研讨会的讲座和NMNH Q？美国科学中心。此外，联合项目负责人将为古生物学系的博客空间创建一系列基于野外和实验室的条目。联合计划还将参与“科学家在”计划，该计划将为公众提供机会，向研究人员询问他们的研究，以及与人类起源相关的其他主题。最后，联合调查官的实地工作将与KFFS一起完成。肯尼亚国家博物馆和华盛顿大学之间的合作为来自肯尼亚、埃塞俄比亚、南非和美国等几个国家的学生提供了古人类学的实地实践经验。

A comprehensive understanding of a species' evolutionary history includes determining the ecological factors that drove its adaptations. All species occupy a particular ecological niche whose breadth is determined by the interplay of abiotic (e.g., climate and dispersal barriers) and biotic (e.g., competition) influences. The niche of a species is rarely static through time and the inevitable changes can result in a variety of outcomes, including further adaptation, speciation and extinction. Although it has historically been difficult to reconstruct the ecological niches of fossil taxa, recently developed paleoecological techniques, mean that it is now possible to test hypotheses about the role of ecology might have played in the separate evolutionary histories of two important early hominin lineages.Determining how our early human ancestors interacted with their environments is fundamental for understanding human evolutionary history. The fossil record suggests that our genus, Homo, originated in eastern Africa around 2.4 million years ago (Ma), and shared the environment with a closely related species called Paranthropus boisei. However, the record also suggests that by approximately 1.3 Ma, the Paranthropus lineage went extinct and Homo had expanded its geographical range outside of Africa. Although these lineages coexisted in time, we lack a logical framework for testing hypotheses related to their ecology during this period. This dissertation project by doctoral student David Patterson (under the supervision of Dr. René Bobe, The George Washington University) will contribute to addressing these gaps in our knowledge by using novel methods to generate the first high-resolution reconstruction of the ecological niches of these two lineages. This project combines quantitative methods from mammalian community ecology with stable isotope geochemistry to investigate the ecological niches of Homo and Paranthropus within a spatially constrained ancient ecosystem. The proposed study will use paleoecological data collected directly from localities where these hominin fossils occur, and from archaeological sites dated to between approximately 2.0 and 1.4 Ma in the Koobi Fora Formation of northern Kenya. By concentrating on specific fossil assemblages within the same region, this study will provide new insights into the ecological niches of these two lineages. The impact of this research will be amplified via the Co-PI's involvement with the Evolution of Terrestrial Ecosystems (ETE) program at the National Museum of Natural History (NMNH) and with the Koobi Fora Field School (KFFS). As part of ETE, the Co-PI will disseminate project results to educators through lectures at sponsored workshops and via the NMNH Q?rius Science Center. Additionally, the Co-PI will create a series of field- and laboratory-based entries for the Paleobiology Department's blogspace. The Co-PI will also participate in "The Scientist is in" program, which will give the public the opportunity to ask researchers about their research, as well as about other topics associated with human origins. Lastly, the Co-PI's fieldwork will be completed in conjunction with the KFFS. This collaborative effort between the National Museums of Kenya and GWU provides students from several countries, including Kenya, Ethiopia, South Africa, and the United States with hands-on field experience in paleoanthropology.