Collaborative Research: Does sexual selection promote speciation and extinction? A test with Late Cretaceous Ostracoda from the US Gulf Coastal Plain

合作研究：性选择是否促进物种形成和灭绝？

• 批准号: 1424904
• 负责人: Rowan Lockwood
• 金额: $ 6.74万
• 依托单位: College of William and Mary
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2017-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1424904&HistoricalAwards=false
• 关键词: Collaborative; Research; Does; sexual; selection

Nontechnical AbstractUnderstanding the factors that control the origin and extinction of biodiversity is a central goal of evolutionary biology and is directly relevant to the conservation and management of biodiversity on the Earth today. Recent research suggests that speciation (i.e., the evolution of new species) and extinction can be affected by sexual selection, a process that occurs when individuals compete with each other for access to mates. To date, tests of this hypothesis have not examined actual speciation and extinction events, relying instead on proxies, such as the conservation status of modern species. Here the researchers test the effects of sexual selection on speciation and extinction using the rich fossil record of tiny crustaceans called ostracodes. These animals are unusual because their sex can be determined from their shells, even as fossils, and the researchers can use the extent to which males and females differ in shell shape and size as a measure of the intensity of sexual selection. In this research, the researchers will relate the strength of sexual selection in ostracode species to patterns of speciation and extinction in samples that span a time interval from 85 to 60 million years ago along a swath of the southeastern United States from Texas to Georgia that was under the sea during this time period. In addition to the scientific goals of this research, the researchers will mentor a post-doctoral scientist as both a teacher and scholar, and involve multiple undergraduate students in the project. The researchers will also develop several public education activities for the Smithsonian Museum of Natural History.Technical DescriptionUnderstanding the mechanisms that underlie species extinction and origination is central to macroevolutionary theory and helps to explain the diversity and history of life. Recent empirical evidence and theoretical models suggest that sexual selection, a form of natural selection that acts upon variation in mating success, can drive both speciation and extinction. To date, tests of the association of sexual selection with either extinction or speciation have relied heavily on neontological data and use weak proxies of actual macroevolutionary events, such as conservation status (for extinction) or clade richness (for speciation). Here the project capitalize on the rich fossil record of ostracodes and propose to perform the first examination of whether sexual dimorphism, an indicator of the strength of sexual selection, is associated with differential rates of actual extinction and speciation.The research provides the first test of the macroevolutionary hypothesis that sexual selection is positively association with both speciation and extinction, focusing on the well-preserved and well-sampled record of Late Cretaceous through Paleocene ostracodes on the US Gulf Coastal Plain (GCP). Specifically, the project will: (1) measure the magnitude of sexual dimorphism?a proxy for sexual selection?using outline-based morphometrics; (2) document the stratigraphic ranges of taxonomically vetted ostracode species from the Late Cretaceous and early Paleocene; (3) test, using likelihood-based model fitting, the influence of sexual dimorphism on the propensity of species to originate or go extinct.

了解控制生物多样性起源和灭绝的因素是进化生物学的一个中心目标，并与当今地球上生物多样性的保护和管理直接相关。最近的研究表明，物种形成（即，新物种的进化）和灭绝都可能受到性选择的影响，性选择是一个个体为获得配偶而相互竞争的过程。到目前为止，这一假设的测试还没有检查实际的物种形成和灭绝事件，而是依赖于代理，如现代物种的保护状况。在这里，研究人员利用被称为介形虫的微小甲壳类动物的丰富化石记录来测试性选择对物种形成和灭绝的影响。这些动物很不寻常，因为它们的性别可以从它们的外壳中确定，甚至作为化石，研究人员可以使用雄性和雌性在外壳形状和大小上的差异程度来衡量性选择的强度。在这项研究中，研究人员将介形虫物种的性选择强度与样本中的物种形成和灭绝模式联系起来，这些样本跨越了沿着美国东南部从德克萨斯州到格鲁吉亚的一条狭长地带，在这段时间内位于海底。 除了这项研究的科学目标外，研究人员还将指导一位博士后科学家作为教师和学者，并让多名本科生参与该项目。研究人员还将为史密森尼自然历史博物馆开展几项公共教育活动。技术说明理解物种灭绝和起源的机制是宏观进化理论的核心，有助于解释生命的多样性和历史。最近的经验证据和理论模型表明，性选择，一种自然选择的形式，作用于交配成功的变化，可以驱动物种形成和灭绝。到目前为止，性选择与灭绝或物种形成的关联的测试在很大程度上依赖于新生物学数据，并使用实际宏观进化事件的弱代理，如保护状态（灭绝）或分支丰富度（物种形成）。在这里，该项目利用介形类丰富的化石记录，并建议进行第一次检查是否性二型，性选择的强度的指标，与实际灭绝和物种形成的差异率。该研究提供了第一次测试的宏观进化假说，性选择是积极的物种形成和灭绝，重点研究美国海湾沿岸平原（GCP）上保存完好、采样良好的晚白垩世至古新世介形类记录。具体而言，该项目将：（1）测量性二态性的大小？性选择的代表使用基于轮廓的形态测量;（2）记录晚白垩世和古新世早期介形虫物种的地层范围;（3）使用基于似然性的模型拟合测试性二型性对物种起源或灭绝倾向的影响。