Doctoral Dissertation Research: Skull Growth and Biomechanical Constraints on Molar Emergence in Primates

博士论文研究：灵长类动物的头骨生长和磨牙萌出的生物力学限制

• 批准号: 1540338
• 负责人: Gary Schwartz
• 金额: $ 1.01万
• 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: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2016-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1540338&HistoricalAwards=false
• 关键词: Doctoral; Dissertation; Research; Skull; Growth

Human life history is unique among living primates. Humans grow slowly and have long lifespans coupled with short inter-birth intervals, resulting in fast reproductive rates. Among primates, there is a strong relationship between life history and the age at which the first permanent molar emerges into the mouth. Paleoanthropologists use this relationship to probe the antiquity of the unique human life history profile, but exactly why molar emergence varies and is closely associated with life history remains unclear. This study will examine molar emergence as part of a developing, functionally integrated chewing system, to provide a model for contextualizing variation in the timing of molar emergence among primates. It will also contribute to understanding the close association between molar emergence and life history. The project will yield a rich public database of 3D primate skull growth with relevance to the study of craniofacial growth and molar impaction, and support public science outreach and training of graduate and undergraduate students in a STEM field. Molars function with the jaws and chewing muscles to break down food. Developmental coordination among these parts of the chewing system is critical for food ingestion throughout life. In adult primates, the configuration of the chewing system constrains the position of molars to avoid damage to the temporomandibular joint during chewing. Using 3D coordinate data from cross-sectional ontogenetic samples of primate skulls (n = 18 species; 1,182 specimens) this study will determine if the position of molar emergence is constrained in the same manner, thereby regulating the timing of molar emergence. This research will examine how ontogenetic changes in the configuration of the chewing system drive variation in molar emergence schedules among primates, and may suggest that life history is closely associated with molar emergence ages through its influence on facial growth rates. It will further suggest that selection for shorter faces and a prolonged growth schedule in the lineage leading to humans would have had the concomitant effect of delaying molar emergence.

人类的生活史在现存的灵长类动物中是独一无二的。人类生长缓慢，寿命长，加上生育间隔短，导致繁殖率快。在灵长类动物中，生活史和第一恒磨牙出现在口腔中的年龄之间有很强的关系。古人类学家利用这种关系来探索独特的人类生活史剖面的古老性，但确切地说，为什么臼齿的出现会有所不同，并与生活史密切相关，仍然不清楚。本研究将探讨磨牙出现的一部分，发展中的，功能集成的咀嚼系统，提供一个模型的上下文变化的时机之间的灵长类动物磨牙出现。这也将有助于理解磨牙出现和生活史之间的密切联系。该项目将产生一个丰富的3D灵长类动物头骨生长的公共数据库，与颅面生长和磨牙嵌塞的研究相关，并支持STEM领域的研究生和本科生的公共科学推广和培训。臼齿与颌骨和咀嚼肌一起起分解食物的作用。咀嚼系统的这些部分之间的发育协调对于整个生命的食物摄取至关重要。在成年灵长类动物中，咀嚼系统的构造限制了磨牙的位置，以避免在咀嚼过程中损伤颞下颌关节。使用灵长类头骨（n = 18个物种; 1，182个标本）的横截面个体发育样本的3D坐标数据，本研究将确定磨牙出现的位置是否以相同的方式受到限制，从而调节磨牙出现的时间。这项研究将探讨如何个体发育的变化，在配置的咀嚼系统驱动的灵长类动物之间的臼齿出现时间表的变化，并可能表明，生活史是密切相关的臼齿出现年龄，通过其对面部生长速度的影响。这将进一步表明，选择较短的脸和延长的生长时间表在血统导致人类将有延迟磨牙出现的伴随作用。