The Effect Of Body Size On The Origin And Diversification Of Birds

体型大小对鸟类起源和多样化的影响

• 批准号: NE/X012395/1
• 负责人: Ryan Felice
• 金额: $ 10.27万
• 依托单位: University College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FX012395%2F1
• 关键词: Effect; Body; Size; Origin; Diversification

Sixty-six million years ago, the end of the Cretaceous period was marked by one of earth's largest mass extinctions. This event resulted in the demise of three quarters of all land animals, including all of the non-avian dinosaurs and many of the birds. Only a few bird species survived, and these groups subsequently diversified into the stunning variety of species we see today. What allowed these few lucky birds to survive? The factors that predispose organisms to extinction or speciation is of the biggest questions in evolutionary biology. This is increasingly important as more species become threatened with extinction today as a result of human-caused climate change. One hypothesis, the "Lilliput effect," proposes that lower body mass increases the chances of survival during a mass extinction. This is because body size affects nearly every aspect of biology, from life span to metabolism to rate of mutations. Although many studies have sought to quantify whether body size and diversification are linked, nearly all of these have excluded a key source of data: the fossil record. This is despite the fact that mathematical simulations predict that calculating extinction rates without including extinct species invariably produces inaccurate results. Here, we seek to answer two main research questions: (1) how did body size affect speciation and extinction rates in birds over the past 175 million years? (2) how does including fossil data in our models affect our reconstructions of diversification through time? We will use measurements of fossil bird skeletons to reconstruct body mass in approximately 400 extinct avian species, including some of the largest birds ever to exist such as the dodo, great auk, and elephant bird. We will then generate a comprehensive family tree of birds including >10,000 fossil and modern species, allowing us to track their evolutionary history through time. Finally, we will use evolutionary modelling to test whether the probability of speciation and extinction are indeed affected by body mass. Using advanced statistical methods and fossil data, we will provide the first test of the hypothesis that small size was a key trait that allowed birds to diversify after the time of the dinosaurs.

6600万年前，白垩纪末期是地球上最大的一次大规模喷发。这一事件导致四分之三的陆地动物灭绝，包括所有非鸟类恐龙和许多鸟类。只有少数鸟类幸存下来，这些群体随后多样化成我们今天看到的令人惊叹的各种物种。是什么让这几只幸运的小鸟活了下来？使生物易于灭绝或形成物种的因素是进化生物学中最大的问题。这一点越来越重要，因为今天由于人为造成的气候变化，越来越多的物种面临灭绝的威胁。一种假说，“小人国效应”，提出较低的体重增加了生存的机会，在大灭绝。这是因为身体大小几乎影响生物学的各个方面，从寿命到新陈代谢到突变率。尽管许多研究试图量化身体大小和多样化是否有联系，但几乎所有这些研究都排除了一个关键的数据来源：化石记录。尽管数学模拟预测，计算灭绝率而不包括灭绝物种总是会产生不准确的结果。在这里，我们试图回答两个主要的研究问题：（1）在过去的1.75亿年里，身体大小如何影响鸟类的物种形成和灭绝率？(2)在我们的模型中包括化石数据如何影响我们对时间多样性的重建？我们将使用化石鸟类骨骼的测量来重建大约400种灭绝鸟类的体重，包括一些有史以来最大的鸟类，如渡渡鸟，大海雀和象鸟。然后，我们将生成一个全面的鸟类家谱，包括> 10，000个化石和现代物种，使我们能够跟踪它们的进化历史。最后，我们将使用进化模型来测试物种形成和灭绝的概率是否确实受到体重的影响。使用先进的统计方法和化石数据，我们将提供第一个测试的假设，小尺寸是一个关键的特点，使鸟类多样化后，恐龙的时间。