Examining the relationship between an increasingly carnivorous Homo erectus and Pleistocene mammal extinctions.

现代人具有无与伦比的能力来改变他们的生态系统。人类何时以及如何获得这种能力还不确定。该项目旨在阐明人类进化史过程中人类生态系统改变的时间和性质。具体地说，该项目使用定量的食物网方法，研究了更新世直立人对食肉的新重视对哺乳动物群落的潜在影响，了解了人类祖先与之竞争肉类的化石捕食者的解剖和同位素组成。该项目通过为学生研究创造新的机会，扩大对古人类学的参与，加强国际、多学科研究合作，并广泛传播成果，包括面向公众的外联活动。古人类影响假说(AHIH)指出，直立人的食肉对更新世哺乳动物群落造成了深远的影响，导致大型食草动物猎物物种和相互竞争的捕食者灭绝。然而，当直立人第一次出现时，他们出现的地区正在经历气候驱动的草原扩张，这可能也是捕食者和猎物灭绝的原因之一。目前尚不清楚是环境变化、人类影响，还是两者的结合最好地解释了更新世哺乳动物的灭绝。该项目在直立人首次出现在化石记录中的地点，使用古食物网方法测试AHIH。对当地食肉动物的解剖学和同位素研究揭示了哪些食草动物物种灭绝了，从而提供了当地社区定量的古食物网模型。数值食物网模拟实验的输出将与AHIH的预测进行比较，以揭示人类祖先对更新世哺乳动物群落的影响(如果有的话)。该项目扩大了对食用肉类对生态系统改造的进化意义的理解。这一奖项反映了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。

Modern humans have an unparalleled capacity to modify their ecosystems. When and how humans obtained this ability is uncertain. This project seeks to clarify the timing and nature of human ecosystem modification over the course of human evolutionary history. Specifically, this project examines the potential impacts of a new emphasis on meat-eating by Pleistocene Homo erectus on mammal communities using a quantitative, food-web approach, informed by studies of the anatomy and isotopic composition of fossil predators with which human ancestors competed for access to meat. The project broadens participation in paleoanthropology by creating new opportunities for student research, enhances international, multidisciplinary research collaborations, and disseminates results broadly, including public-facing outreach events. The Ancient Hominin Impacts Hypothesis (AHIH) states that meat-eating by Homo erectus caused profound impacts on Pleistocene mammal communities, driving both large herbivore prey species, and competing predators to extinction. However, at the time Homo erectus first appeared, the region in which they appeared was experiencing climate-driven grassland expansions, which may also have contributed to extinctions in predators and prey. It is currently unknown whether environmental change, human impacts, or a combination of both best explains the observed Pleistocene mammal extinctions. This project tests the AHIH using a paleo food webs approach at the site where Homo erectus first appears in the fossil record. Anatomical and isotopic studies of local carnivores reveal which herbivore species extinct carnivore consumed, informing a quantitative paleo food-web model of the local community. The outputs of numerical food-web modeling experiments will be compared to the predictions the AHIH to reveal what impact, if any, human ancestors had on Pleistocene mammal communities. The project expands an understanding of the evolutionary significance of meat eating to ecosystem modification.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.