CAREER: Quantifying Genetic and Ecological Constraints on the Evolution of Thermal Performance Curves

这项研究项目将研究一种单细胞生物--嗜热四膜虫--如何适应不断变化的温度。它旨在通过研究属于地球上最丰富的物种之一--被称为原生生物的单细胞生物--的物种是否以及如何随着气温的上升进化得更快，以及决定这种进化的生物因素，来解决我们对全球气候变化可能如何迅速影响所有生物的理解上的一个关键差距。回答这个看似简单的问题会产生无数的社会影响。事实上，在更温暖的温度下朝着更快的生长方向进化，预计还会导致呼吸速率增加--生物有机体通过燃烧糖来获取能量，同时释放出二氧化碳--这是一种强有力的温室气体--这反过来会加剧气候变化。此外，由于许多原生生物是导致疟疾和昏睡病等疾病的人类病原体，了解它们在不断变化的气候中的演变对公共健康至关重要。最后，这个项目致力于通过赋予来自不同背景的学生更广泛的科学参与，从而促进他们在生态学和进化生物学领域的学术和专业成长。我们的研究将热生态学、种群和群落生态学与遗传水平的过程联系起来，负责确定嗜热四膜虫种群增长率(r-TPC)的热性能曲线，四膜虫是一种具有世界性分布和重要性的微生物物种，拥有大量的基因变异库。该项目将使用微观实验和数学模型。在目标1中，将使用由50个独特的遗传菌株组成的模型种群来量化嗜热葡萄球菌r-TPC的种内变异(遗传、环境和基因-环境交互作用)。这些数据将量化r-TPC在该模型种群中的选择和进化能力，以预测变暖下可能的进化轨迹。目标2将在实验上量化在变暖下的短期和长期r-TPC的演变，并确定其可预测性。目标3将评估竞争和捕食如何影响简化的水生微生物食物网中r-TPC的形状演变。该奖项反映了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。

This research project will examine how a model, one-celled organism - Tetrahymena thermophila – adapts to changing temperatures. It aims to resolve a critical gap in our understanding of how rapid global climate change may affect all living organisms by studying whether and how a species belonging to one of the most abundant groups on Earth – one-celled organisms known as protists – may evolve to grow more rapidly as temperatures increase, and the biological factors that determine that evolution. Answering this seemingly simple question has myriad societal impacts. Indeed, evolution towards faster growth at warmer temperatures is also predicted to result in increased respiration rates – the process through which living organisms burn sugars to obtain energy while releasing carbon dioxide, a potent greenhouse gas – which would in turn worsen climate change. Additionally, since many protists are human pathogens responsible for diseases like malaria and sleeping sickness, understanding their evolution in changing climates is crucial for public health. Last, this project commits to broadening scientific participation by empowering students from diverse backgrounds, thus enhancing their academic and professional growth in the fields of ecology and evolutionary biology.Our research links thermal, population, and community ecology to the genetic-level processes responsible for determining the thermal performance curve of population growth rates (r-TPCs) in Tetrahymena thermophila, a microbial species of cosmopolitan distribution and importance, and which has a large library of genetic variants. The project will use microcosm experiments and mathematical models. In Aim 1 will quantify intraspecific variation (genetic, environmental, and genotype-environment interaction) in T. thermophila r-TPC using a model population composed of 50 unique genetic strains. These data will quantify selection and evolvability of r-TPCs in this model population to predict possible evolutionary trajectories under warming. Aim 2 will quantify experimentally the evolution of r-TPC in the short- and long-term under warming, and determine its predictablity. Aim 3 will assess how competition and predation influence r-TPC shape evolution within a simplified aquatic microbial food web.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.